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YAWL Editor user manual

1. J Task Icon No Icon N E o 18 Manual O Approve o iy Automated Prepare is ii Travel Form Routing Travel Form Admin y Plugin Employer O l FO a O Arrange P2 Submit Travel Travel Form Insurance for Approval y Reject Prepare P3 tau Travel Form Travel Form Secretary de Use the palette toolbar to edit the selected net Figure 1 65 The result of committing a process model configuration While hiding a port is a safe operation blocking a port may lead to behavioral anomalies such as deadlocks If we now blocked the input port of the task Check and Update Travel Form we could cause a deadlock in condition P3 because if task Prepare Travel Form Secretary fired a token would remain stuck in that condition So it would be wise to also block the input port of task Prepare Travel Form Secretary so that P3 could never get control The YAWL Editor provides a Configuration Correctness Checker which can be used to prevent possible behavioral issues already during configuration by excluding those combinations of blocked ports that will lead to an unsound individualized YAWL model In this way you don t need to individualize a process model to find out only later that the configuration you used led to an unsound model The Configuration Correctness Checker needs an external tool namely Wendy 4 which must be located at the path specifie
2. a Keep open when analysis completes Close is Figure 1 66 Output from Wendy Now launch the Configuration Correctness Checker for the travel requisition process Once the analysis has been completed the YAWL Editor will be able to automatically block or activate further ports in an interactive way i e as you configure your model Let s now block the input port of task Check and Update Travel Form which was previously just hidden The Editor will react to that configuration by also blocking the input port of task Prepare Travel Form Secretary to avoid possible deadlocks in the individualized model This is notified to the user via a dialog window see Figure 1 67 Figure 1 68 shows the preview of the resulting individualized model You can see that condition P3 will also be removed from the net now as a result of applying this configuration Automatic completion also works when you activate ports that were previously blocked Try now to activate the input port of task Prepare Travel Form Secretary Since the input port of Check and Update Travel Form is blocked a token may again get stuck in P3 so the Editor will also activate the latter port The following parameters related to C YAWL models can be customized from the menu Settings gt Process Configuration Settings e Set new elements configurable new tasks are set as configurable automatically manually default option
3. e Preview process automatically the preview of configured processes is always switched on the corresponding button on the tool bar becomes inactive the preview can be switched on or off manually default e Deny blocking input ports input ports cannot be blocked can be blocked default e Allow changing default configurations default configuration values can be changed default cannot be changed For more information on C YAWL please refer to the Process Configuration book chapter of the YAWL Book 3 and go to www processconfiguration com For technical details you can also read the scientific paper 2 1 13 CONFIGURABLE YAWL 71 O YAWLEditor D Users marcello Desktop Tools Synergia Synergia 0 7 Synergia Examples 0 7 C YAWL models C YAWL travel requisition yawl SS A 4 Input Ports Configuration Configuration blocked Source Nodes gt Approve Travel Form Activate Hide Use Default 4 Message The Task Prepare_Travel_Form_Secretary s input port 0 has been automatically blocked Prepare Pm Check and Travel Form Update Secretary Travel Form A Request for change m Q Use the palette toolbar to edit the selected net Reject Travel Form Figure 1 67 Notification of ports that are automatically blocked O YAWLEditor D Users marcello Des
4. Figure 1 52 An output parameter set to copy from expression for an automated task 1 9 1 Codelets Essentially a codelet is a discrete Java class managed by the Resource Service that may be enacted by an automated task at runtime When an automated task is enabled during process execution and it has a codelet associated with it the input parameters of the task are passed to the codelet it is executed and any results are passed back to the task via its output parameters There are currently three codelets available in the Editor see the YAWL Technical Manual for directions on how to add user defined codelets e ExampleCodelet designed to demonstrate the usage of codelets e XQueryEvaluator accepts an XQuery as an input parameter evaluates it using other input parameters as required by the XQuery and produces the result to an output parameter e ShellExecution accepts an input parameter containing a command line of an external program and runs it waiting for it to complete and returning the result if any via an output parameter To associate a codelet with a task decomposition first mark the decomposition as automated by ticking the Automated checkbox in the Task Decomposition dialog see Figure 1 29 When checked the Set Codelet button is enabled clicking that button opens the Set Codelet for Automated Decomposition dialog listing the available codelets Figure 1 53 Note that a valid connection to the Resource Service
5. YAWL User Manual Version 2 1beta E 2010 The YAWL Foundation Contents 1 The Editor 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1 11 1 12 1 13 1 14 1 15 Launching the YAWL Editor lt a ad a kw E E ARE The YAWL Editor Workspace 2 a a a a a Creating Your First Specification e886 SS Se ik i Ue Bw we a BE we A eee 12 Changing the Appearance of Your Specification 23 Additional Specification Features 26 COON COONS acido op de A A A Pi Pe gt Ek tes 49 Validating and Saving a Specification e s s ss ras aa dde A AAA e 52 Specie ONARA ad de ta a da a A 54 Atom 2 amp amp a arado a A ee Oe oe ees ae 57 Resource Management Manual task o e ee 59 asi Mer e tre A a A AAA a 62 CUSTORCEOLNS AF amp oa Hehe ae A da dd A AA Y 65 Connon DA AWI 2 adi er thee ee a ee ee te a AA ace ee 66 Configurable Logging y ye eae eee ERE EEE CAREY EAS MERE RE SSS T2 Extended AttriDUtes ss sa nai a EWR EME D aR ee Ee T4 CONTENTS Chapter 1 The Editor Before a workflow model can be executed it must first be defined This chapter describes the YAWL Editor version 2 1 a tool for creating editing configuring validating and analysing workflow specifications New users are encouraged to read the chapter sequentially experienced users may pick and choose what they need from this chapter Figure 1 1 illustrates the interactions among some of the major components of the YAWL environm
6. e Round Robin by time chooses the participant in the set who has not been allocated a task instance for the longest time e Round Robin by least frequency chooses the participant in the set who has been allocated this task instance the least number of times in the past e Round Robin by experience chooses the participant in the set who has been allocated this task instance the most number of times in the past e Random Choice randomly chooses a participant from the set the default and e Shortest Queue chooses the participant in the set who has the least number of task instance currently in their work queue ODO Manage Resourcing Wizard for Atomic Task Raise purchase order Step 4 System Allocation An allocation strategy is a way of dynamically selecting one participant from those resources that have been offered a task and have the task allocated or assigned to the chosen participant Each allocation strategy uses a different method to choose a participant Please choose the preferred strategy from those listed below Allocation strategy Round Robin by experience 34 lt Back gt Next Finish Figure 1 57 Step 4 of the resource management wizard Step 5 In Step 5 shown in Figure 1 58 we can specify participant task privileges privileges that apply only for this task For example we can specify whether participants are allowed to suspend the execution of work items of the selected
7. Begin My Career and to Get A Job tasks Your updated net should look like Figure 1 14 and should validate successfully The Knowledge Gained condition in Figure 1 13 shows an example of a Deferred Choice construct When the condition is reached during execution of the process both of its outgoing flows are activated note that a condition may have any number of outgoing flows This results in both the Look for an Easier Book and Feel Smarter tasks appearing in the user s worklist allowing the user to make a deferred choice between the two As soon as the user chooses the appropriate task for execution the other task is immediately withdrawn and is removed from the worklist 1 3 6 Changing the Starting Net At any stage you can change the Starting Net of the specification To change the Starting Net 1 Select Net from the Menu 2 Choose Set Starting Net Figure 1 15 1 4 CHANGING THE APPEARANCE OF YOUR SPECIFICATION 23 O Attend University O Study Privately Begin My Attend Get a job Career Career University k Started Study Privately Figure 1 14 Making the Study Privately task an atomic composite 3 From the Choose Starting Net window click on the drop down list and select a new starting Net 4 Click Done 600 Choose Starting Net Execution of the workflow starts in net y Attend Universit My Career Study Privatel Done Cane Sul y E Figure 1 15 Changing t
8. amp Output Then open the Update Parameter Mappings dialog add an input parameter mapping the net level Masterlist variable to the task s bookList variable and an output parameter to map it back again see Figure 1 38 This task will allow a user to add any number of book orders to the master book list 606 Update Parameters for Atomic Task Create Book List Input Parameters XQuery Task Variable _ Create Tist Builder MasterList bookList Update Remove Task Variables Name Type Usage bookList BookList Input amp Output Net Variables Name Type MasterList BookList Output Parameters XQuery Net Variable Create Create Book List bookList MasterList Update Remove Figure 1 38 Update Parameter Mapping dialog for task Create Book List e Add a decomposition to the other atomic task and call it Show List Add a variable to the decom position similarly to the first task except that the usage should be Input Only and so only an input parameter mapping is required This task will show the user the results of any data changes done during the execution of the MI task thus its variable is input only meaning that the values are display only e Add a decomposition to the MI task and call it Verify List To the decomposition add a variable called book of type BookOrder and usage Input amp Output Note carefully that the task variable we have added to th
9. one from task tau the other from task Check and Update Travel Form and three output ports one towards task Approve Travel Form Admin one towards task Reject Travel Form and one towards task Request for Change while the latter task only has one input port and one output port To make a task configurable you can right click on it and select Process Configuration gt Set Task Configurable For example let s make task Submit Travel Form for Approval configurable Now we are ready to configure this task All ports are activated by default You can configure them by either blocking or hiding them 1 13 CONFIGURABLE YAWL 67 YAWLEditor D Users marcello Desktop Tools Synergia Synergia 0 7 Synergia Examples 0 7 C YAWL models C YAWL travel requisition yawl Specification Net Edit Elements Settings View Help Baja v G 2 A Oj 6 New_Net_1 J Task Icon No Icon o Manual d q Approve e Automated Prepare ea gt Routing Travel Form y Plugin employer Travel Form Admin Submit Travel Form for Approval Insurance NM Reject Prepare Check and Travel Form Travel Form Update Secretary Travel Form gt Request for change de Y Use the palette toolbar to edit the selected net Figure 1 62 A C YAWL model for travel requisition me e Inp
10. Close the offending dialog window to re enable use of the YAWL Editor I can t connect two elements with a flow Why The Editor will not allow you to connect one element to another where such a connection is invalid Typical examples include e Trying to connect a second flow to an undecorated task e Trying to point an incoming flow to a split decorator or an outgoing flow from a join decorator See the troubleshooting entry How do I find out more about elements and principles for more details When I validate my Net I get the following validation message The net may complete without any generated work Should all atomic tasks in the net be unlabelled This message appears if none of your atomic tasks are associated with a decomposition To add a decom position to a task and thus ensure that the engine will get a user to handle the task at this point in the workflow right click on the task and choose Select Task Decomposition Choose Create and in the following window Update Task Decomposition and enter the name of your task under Decomposition Label then click Done My specification won t validate without any errors and I don t know what to do First check the logic of your specification and exercise every branch of your workflow for correctness If you are sure of your workflow consult the YAWL website for the proper use of the YAWL elements http yawlfoundation org H
11. Creating Splits and Joins To create a split or join 1 Select a task When a single task is selected the Decorator panel will appear with two tabs that allow you to decorate a task with a split and or join You can also choose a fill colour to help visually differentiate splits from joins with the expanded colour palette Choose the required split or join and the orientation which edge of the task to attach the decoration to for the split or join to appear In our example select the Begin My Career task and in the Decorator panel select an XOR split Then set the orientation to eastern edge of the task as per Figure 1 8 Create a new Atomic task called Do Private Study This task will represent those students that choose not to go to University Finally select your Get A Job task and decorate it with an XOR join Then set the orientation of the join to the western edge of this task Split and Join decorators allow you to connect several Flow Relations from and to your task respectively Create a flow relation from Begin My Career to Do Private Study then create another flow relation from Do Private Study to Get A Job as per Figure 1 8 4 Don t forget to check the validity of your specification Hint If you are having trouble with positioning your tasks the alignment tools are a big help When Begin My Career has been completed a choice must be made on which o
12. Parameter Expression and the Instance Query exactly matches the Output Parameter Expression as can be seen in Figure 1 41 The Splitter Query in this example is a little simpler than the earlier one since we don t have to worry about different tag names for the split data because out task level variable has the same name as its data type so it takes the less complicated form for s in Suppliers return s for each Supplier in the list of Suppliers return that Supplier The Aggregate Query takes the same form as the previous example When the instance creation type is set to dynamic then new instances of the MI task may be created at runtime after the task execution has begun and split into its instances There is a button on the default 1 6 CONNECTIONS 49 worklist handler to accommodate this see Chapter which will be enabled for dynamic MI tasks until such time as the maximum instances bound has been met 1 5 10 Fast Tracking Data Definition If all of a task s input and output parameters will involve a simple mapping to and from net level variables a fast track can be taken to do it all in a few mouse clicks To achieve this right click on an atomic task that does not yet have a decomposition and select Decompose to Direct Data Transfer The dialog in Figure 1 43 will appear BOB Atomic Task Select a number of net variables to be used as input to this task Do the same for output The selected net variables will ha
13. Successfully connected to a running YAWL engine Done Cancel A AAA Figure 1 44 Specifying the YAWL Engine connection detail The YAWL Engine URI value is set by default to a locally installed Engine http localhost 8080 yawl ia but should be changed if the Engine is installed remotely The User Name and Password have the following case sensitive defaults but can be changed via the Client Applications web form Section e user name editor e password yEditor As a user convenience a button called Test Connection is supplied which will test a connection to a running engine with the detail supplied for correctness before you are committed to using those details for any further editor engine interactions To finalise the connection settings click the Done button 1 6 2 Connecting to the Resource Service To use the organisational data managed by the Resource Service for assigning tasks to Participants or Roles a connection between the editor and the Resource Service needs to be established Like the Engine connection above when the Editor starts a connection to a running Resource Service is attempted If successful the Resource Service connection icon at the left of the status bar will turn green 1 6 CONNECTIONS ol If unsuccessful perhaps because the Service is not running or the connection parameters are incorrect the connection icon will show red After the Editor has started a Resource Service connection may b
14. The custom service handling this work item is item handlingservice namel It was started now and enabled S item enabledtime It has a timer status of item timer status On Completion This work item was performed by participant namel who had participant allocatedQueueSize items on their allocated queue On completion the item s timer status was Sfitem timer status Done Cancel Figure 1 70 Entering work item level log predicates Bano Update Task Variable SubjectCode Standard Extended Attributes On Input The extended attribute optional of parameter parameter name has value S parameter attribute optional r r Done Cancel Figure 1 71 Entering variable level log predicates 76 CHAPTER 1 THE EDITOR Attribute Default background alt color The background color of alternating form panels light blue hex D3E0FC background color The main background color of the form blue hex 97CBFD font color Font color for labels black font family Name of the font family used browser default font size Size of the font used 12 point font style None or Bold or Italic or both None header font color Font color for headings dark teal hex 3277ba header font family Name of the font family used for headings browser default header font size Size of the font used for headings 14 point header font style None or Bold or Italic or both Bold hideBanner Suppress display of the YAWL banner
15. a Job 4 Create a new Net by clicking on the Create a New Net button E on the Menu Toolbar or click on the Net Menu and choose Create Net 5 Choose a name for this Net by clicking on the Net Menu and choosing Update Net Detail We are going to call this new Net Attend University 6 Return to your original Net and right click on your Composite Task and choose Unfold to net You will then be given a drop down list with all the Nets available choose the Net this task is to represent and then click Done Tip you can also combine the last three steps by simply right clicking on the newly added composite task selecting Unfold to net then clicking the Create button in the dialog that appears Choose Attend University You can now fill out the detail of your new Attend University Net Create the following Atomic Tasks in order and then link them with Flow Relations and don t for get to check for validity e Enrol e Do Subjects e Pass All Subjects e Get Degree The resulting nets are shown in Figures 1 9 and 1 10 18 CHAPTER 1 THE EDITOR Ol Attend University E Get ajob Career Started Attend University Begin My Career Do Private Study Figure 1 9 Parent net with Attend University Composite Task f lr My Career gt gt _ _F A Do Subjects Pass All Get Degree Subjects Figure 1 10 The Atte
16. above image above align image below image below align justify label length line above line below maxExclusive maxInclusive maxLength minExclusive minInclusive minLength optional pattern readOnly skip Validation text above text below text area tooltip totalDigits whiteSpace A tailored validation error message The background color of the field Show field blacked out unviewable if true Font color for the field amp label Name of the font family used Size of the font used None or Bold or Italic or both Number of digits to show after the decimal point Hide the field from view if true Hide the field from view if the XQuery value evaluates to true URL for an image to show above the field Alignment for image above the field URL for an image to show below the field Alignment for image below the field Justify text in the field Text for the field label Exact number of characters required Draw a horizontal line above the field if true Draw a horizontal line below the field if true One less than the upper range of valid values accepted Upper range of the valid values accepted Maximum number of characters required One more than the lower range of the valid values accepted Lower range of the valid values accepted Minimum number of characters required Field does not require a value if true Field value must match the value pattern Field value can t be modified if true Don t validate valu
17. extension for variable level attributes However the property files can be placed in any folder and use any filename in that case the location of the particular property file must be set in the External File Paths dialog Settings External File Paths The Editor will always look for the file in the last folder filename set or the default path filename if never set Extended attributes are listed in the Update Task Decomposition dialog see Figure 1 72 for an example with some values set and the Update Task Variable dialog The default attribute set is listed alphabetically in black text while any user defined attributes are listed alphabetically in blue text below the default set Attributes are defined as key value pairs the key represents the name of the attribute and the value its type The available attribute types are e boolean may be given a value of true or false Rendered as a checkbox in the Extended Attributes tab e string a simple text string Rendered as a text field e color a color value Renders as a text field with a hex RGB value 1 15 EXTENDED ATTRIBUTES 19 e font a valid font name Renders as a text field e integer a valid integer value Renders as a text field Invalid entries are ignored e double a valid double value Renders as a text field Invalid entries are ignored e enumeration a set of string or numeric values Renders as a dropdown dialog e xquery a
18. in Figure 1 2 Specification Net Alignment Cancellation Maintenance Maintenance Options Sets Specification Net Edit Elements Tools View Help eee y a e all a a afe alu RIKE Specification Verification Edit Size Zoom and Analysis Options Options Options Wf Elements amp ci Task Icon Tools Ho Icon o Manual o te Automated o u Routing y Plugin Task icons Modeling canvas EE NONE AND E E XOR OR Decorations Notes amp Problems panel Invalid Resource References An invalid resource reference in Task Loss Or Damage Management of Net Loss_0r_Damage_Management has been removed n invalid resource reference in Task Process Freight Payment of Net Process_Freight_Payment has been removed A An invalid resource reference in Task Prepare Transportation Quote of Net Carrier_Appointment has been removed An invalid resource reference in Task Arrange Delivery Appointment of Net Carrier_Appointment has been removed oO Use the palette toolbar to edit the selected net Hints amp Messages Engine Status Resource Service Status Figure 1 2 The YAWL Editor Workspace 1 2 THE YAWL EDITOR WORKSPACE 7 1 2 1 The Toolbar The Menu Toolbar contains nine groups of buttons to assist you in maintaining your YAWL specification The toolbar can be repositioned by dragging the left hand anchor bar Each button may be enabled or disabled at certain times depending on what you are
19. is required for this list to be populated with codelets The dialog lists the available codelets together with a description of what each one does and the task variables required to successfully execute it For example if ExampleCodelet is chosen the automated task requires 3 variables to be created input parameters a and b and output 1 10 RESOURCE MANAGEMENT MANUAL TASK 99 8000 Set Codelet for Automated Decomposition Marne Description This codelet is a simple example of codelet construction and usage It adds two integers Required parameters Inputs a b both long types Output c also a long his codelet executes an external program Required Inputs command type String required ShellExecution env attrib value pairs optional ExampleCodelet dir type String optional utput result type String This codelet executes an XQuery Required parameters Input query type String required the XQuery plus other values used by the XQuery Output result type String XQueryEvaluator OK Cancel Figure 1 53 The Set Codelet dialog variable c all of type long These parameters must be added to the task in the normal manner at runtime if the required variables are not present the codelet will be unable to successfully complete the task will still complete successfully however The codelet repository has been designed as pluggable so that designers and developer
20. meaning of life the universe and everything is 4 Answer answer text The effects of setting the attribute values listed can be seen in Figure 1 77 Remember that nothing has changed in the specification except for the setting of the extended attributes listed Notice that we have hidden the display of the field itself because we have embedded the variable s value in the text below attribute via an XPath expression This is a quite powerful construct allowing usages like e Total charge number Order subtotal text number Order tax text e You if number Exam score text gt 50 then passed else failed the exam e if boolean Question response text then Correct else Sorry try again assumes the re sponse variable has a value of true or false Boe YAWL 2 1 Edit Work Item G AQ Google THE ANSWER TO THE MEANING OF LIFE THE UNIVERSE AND EVERYTHING IS ES J se compu jel Figure 1 77 The dynamic form for the Answer task with certain extended attributes set Editor Troubleshooting The YAWL Editor is not responding to my mouse clicks and it is beeping every time I click the mouse 1 15 EXTENDED ATTRIBUTES 83 Check to see if you have any Editor dialogs open To do so in Windows hold down the ALT key for OSX hold down the Command key and press the TAB key until you reach the dialog window then let go of the keys
21. most recent specifications loaded or saved in the Editor so that one can be selected to be opened saving the trouble of navigating to it via the file open dialog If you hover the mouse over a listed file for a moment a tip will appear showing the file s full path e Print prints the entire loaded specification graphically e Update the Specification Properties such as specification name author description and so on e Update Datatype Definitions where you can define your own data types to be used in the specification Net In addition to the Net Maintenance toolbar items this menu also contains these sub items e Set Starting Net for specifications containing several nets this item allows you to specify which of them is the starting net i e the net that begins execution of the workflow instance e Update Net Detail shows a dialog where you can set the name of the net and create update remove net level variables e Export to PNG Image saves a graphical image of the net to a file e Net Background Colour set the background colour of the selected net e Net Background Image set the background image of the selected net e Print Net prints the currently selected net graphically e Process Configuration a sub menu containing three items Preview Process Configuration shows a preview of the effect of the current process configuration settings Apply Process Configuration applies the
22. on the mouse button Below are the edit options e Cut Copy Delete e Align e Size Increase Decrease to change the appearance of the objects This can also be done using the CTRL key plus Up or Down arrow on your keyboard Note also that whenever you have selected a number of net elements pressing one of the arrow keys will move the selected elements in the direction of the arrow key and pressing the CTRL key plus the A key will select all the elements in the currently selected net 1 43 Changing Font Size You can change the size of the font used to label tasks and conditions 1 Change the font size by clicking on the View Menu and choosing the Label Font Size option 2 Change the font size to that desired The specified font size applies to all text drawn on the canvas 26 CHAPTER 1 THE EDITOR 1 4 4 Changing Task Icons You can add or change the icon that is shown on atomic tasks 1 Select any single atomic task in your workflow The palette will expand to include a task icon tree depicted in Figure 1 13 where you can an icon from the tree to the task You are free to assign any icon Icons have no runtime effect on the engine and are provided simply to make specifications more easily understood by people looking at the specification in the editor 1 4 5 Using Custom Icons Workflow designers can plug in and use their own icons for specification design Icons must be of the PNG file format and be a m
23. task More details on resource allocation and authorisation can be found in Chapter 1 11 Task Timer Any atomic task can be assigned a timer behaviour by right clicking on it and selecting the Set Task Timer The dialog in Figure 1 59 will appear 1 11 TASK TIMER 63 QO a Manage Resourcing Wizard for Atomic Task Approve Step 5 Establish Default User Runtime Privileges for this Task Can a participant suspend a started work item of this task No Yes Can a participant reallocate a work item of this task to another participant resetting state No Yes Can a participant reallocate a work item of this task to another participant retaining state No Yes Can a participant deallocate themselves from a work item of this task No Yes i hana i Can a participant delegate a work item of this task to another participant No Yes Can a participant skip a work item of this task No Yes lt Back gt Next Figure 1 58 Step 5 of the resource management wizard 00068 Set Timeout Detail for Atomic Task Approve pp Y Task is required to timeout Timeout 0 dynamically via net variable approve Timer 4 at the ti f fay jay _ ya at the time o 17 07 2008 El 10 55 58 after a duration of 5 k F Timer begins upon work item enablement 6 upon work item starting Done Cancel Figure 1 59 The timer dialog for an atomic task Fr
24. the name of the variable leave the type as string and set the Usage to Input amp Output Figure 1 28 Click Done Create another variable for the same task called SubjectCode with type string and usage of Input amp Output Click Done 5 The Enrol task now has two variables StudentNumber and SubjectCode Figure 1 29 1 5 7 Task Parameters A parameter defines how a value is assigned to a variable and how a value is passed between net level and task level variables and vice versa Both Input and Output Parameters can be assigned to any tasks depending on their usage type to allow the passing of state between nets and their tasks and between tasks and workflow engine users and web services Data may also be assigned to and from net and or task variables directly from an external data source more later in this section Defining Parameters with XQuery Parameters may be defined using XQuery expressions Input Parameters use an XQuery expression to specify a value possibly drawing on a number of static and or net level variable values that can be passed 2 An examination of the XQuery language is beyond the scope of this chapter good XQuery learning resources can be found at www w3schools com xquery default asp and www xquery com developers 1 5 ADDITIONAL SPECIFICATION FEATURES 39 006 Update Task Decomposition Standard Extended Attributes Log Predicates ____ T
25. you have the View Cancellation Set option ticked e You can create multiple Cancellation Sets in your workflow by selecting another task and choosing the View Cancellation Set option Only one cancellation set may be viewed at any one time 28 CHAPTER 1 THE EDITOR Order from Amazon Order from Booktopia Details Order from Bookfinder Figure 1 20 A Cancellation Set specified for the Order from Amazon task e All flows leading to or from explicit conditions are not valid cancellation set members Neither are the Input and Output conditions The editor will ignore them if you select them for inclusion in a task s cancellation set A task may be included as a member of its own cancellation set The reason for including preceding flows of a task in a cancellation set is this If a flow relation connects two tasks directly then it is said to contain an implicit condition If there is a condition object in the model between two tasks so that the connection is task flow condition flow task for example the Knowledge Gained condition in Figure 1 16 it is said to be an explicit condition In either case when a task completes it passes control to the condition preceding the next task in the flow When the next task is started it takes control from its preceding condition whether implicit or explicit If there is a chance that the tasks in a cancel
26. Enter your XML Schema Data Type Definition into the dialog box See Figure 1 21 Update Data Type Definitions aje de editimenu lt xs schema xmlns xs http www w3 org 2001 x LSchema gt lt xs complexType name Geek gt XS i Sequence gt lt xs element name Name type xs string gt lt xs element name Salary type xs double gt lt x81Sequence gt lt xs icomplexType gt lt xs icomplexType name Book gt xs sequence gt lt xs element name Title type xs string gt lt xs element name Autor type xs istring gt lt xStsequence gt lt xs complexType gt lt xs complexType name Booklist gt lt xs sequence maxOccurs 5 gt lt xsielement name Book type Book gt lt xs sequence gt lt xs complexType gt lt xs schema gt Figure 1 21 Adding the Geek complex data type 3 If the definition text is green your new data type is a valid definition and may be used for defining Net or Task variables in your specification If the text is red there is something wrong with your data type definition and the data type will not be available When the text is red the split pane will reveal a table listing parse errors that were collected when determining the validity of the text supplied An example of this is shown in Figure 1 22 Open the Data Type Definitions dialog and type in the XML text that appears in Figure 1 21 The above example creates a complex data type call
27. ING YOUR FIRST SPECIFICATION 19 Ol Attend University Career Started Attend University Begin My Career Do Private Study Figure 1 11 Adding a Multiple Atomic Task Multiple Atomic Task Do Private Study Instance Detail Minimum Instances 5 Maximum Instances is infinite is equal to 100 Continuation Threshold is infinite is equal to Instance Creation Static Dynamic Done Cancel de Figure 1 12 Instance Bounds on Multiple Instance Tasks for the task will be between the values given for Minimum Instances and Maximum Instances Static mode means the number of task instances started cannot vary once the task is activated Dy namic mode means the same number of task instances as static mode are started initially but new instances of the task may be started dynamically at runtime i e after task execution has begun up to the value entered in Maximum Instances 20 8 CHAPTER 1 THE EDITOR Set the Instance Creation type to Static Set the Minimum Instances value This is the minimum number of instances of this task that will be started when the task is activated Set the Minimum Instances to 5 Set the Maximum Instances value This is the maximum number of instances of this task that can be created from this task Set the Maximum Instances to 100 Set the Continuation Threshold value The moment all task insta
28. Process Configuration button oI from the tool bar or from the menu Net gt Process Configuration Figure 1 64 shows the preview of the configuration in our running example Task Request for change and its input and output arcs have been greyed out whereas task Check and Update Travel form is still in the model this task will actually be replaced with a silent task once the configuration has been committed To remove a preview simply press again on the respective button on the tool bar O YAWLEditor D Users marcello Desktop Tools Synergia Synergia 0 7 Synergia Examples 0 7 C YAWL models C YAWL travel requisition yawl Specification Net Edit Elements Settings View Help Bela y aa a Welase New_Net_1 J Task Icon No Icon o Manual Approve o Automated A iz Travel Form i ravel Form Admin Employer y Plugin Travel Form for Approval Reject Prepare gt Check and eee i aia Travel Form Secretary Travel Form Request for change Ae Y Use the palette toolbar to edit the selected net Figure 1 64 The preview of a process model configuration ra To commit a configuration you need to press the Apply Process Configuration button al from the tool bar or from the menu Net gt Process Configuration This operation generates an individualized YAWL model i e a regular YAWL model where 1 13 CONFIGURABLE
29. Release the mouse button to attach the flow to its new home Take the current flow relation and move it from the top of the task to its side as depicted in Figure 1 16 j My Career D Attend University O Stu Look for an Easier Book Read a Book Knowledge Feel Smarter Gained Figure 1 16 Adding bends to a Flow Relation Adding Labels It is also possible to add labels to flows To do so double click on a flow A small text input box will appear over the flow Type your desired text and commit the flow label by pressing the ENTER key You may then drag that flow label around to position it as desired Take the two flow relations that have recently had bends added to them Attach the label yes to the flow relation going from the Knowledge Gained condition to the Feel Smarter atomic task Attach the label no to the flow relation going from the Knowledge Gained condition to the Look for an Easier Book atomic task Drag the labels about to a desired position much like what s been done in Figure 1 16 Note that Figure 1 17 shows flows using two different line styles The flow running from Look for an Easier Book has been given the spline line style in this figure while the remaining flows are all orthog onal resulting in sharp edged bends on flows such as the one running from the Knowledge Gained condition to the Look for an Easier Book task 1 4 CHANGING
30. S All values start with P for Period followed by a non negative number of years months days then T for time followed by a non negative number of hours minutes and seconds The seconds value can have a decimal point and as many digits following the point as required e g to specify fractions of a second Any zero value parts can be omitted Valid examples P1Y4M3DT23H55M1 5S P2M3D PT10S Care should be taken when specifying a duration for example P2M may mean a different number of days depending on what month it is started in In addition to the methods described above timer parameters may also be set at runtime via a declared variable of type Y TimerType so that values can be supplied and late bound to a task s timer settings To use this deferred approach 1 Create a net level parameter of type YTimer T ype 2 Choose a task right click on it and choose Set Task Timer to open the Set Timeout Detail dialog Figure 1 59 click the dynamically via net variable option and select the net level parameter created in Step 1 1 12 CUSTOM FORMS 65 3 Map the net level parameter to another previous task in the flow which will be used to capture the required values from a user at runtime Those values will be used to set the timer parameters on the task selected in Step 2 The values requested are e Trigger when should the timer start There are two valid trigger values OnEnabled and OnEx ecuting e Expir
31. THE APPEARANCE OF YOUR SPECIFICATION 25 Setting Colours For nets the default background colour can be set i e applied to all nets by choosing Default Net Background Colour from the View menu To set the background colour of individual nets choose Net Background Colour from the Net menu For tasks and conditions the default fill colour i e for all newly added tasks and conditions can be set by choosing Default Element Fill Colour from the View menu For individual tasks and conditions right click on it then choose Set Fill Colour from the popup menu Several selected tasks and or conditions can have their fill colour set at the same time by choosing Set Selected Fill Colour from the Elements menu 1 4 2 Editing Objects My Career O Attend University O Study Pri Look for an Easier Book Mi gt se Feel Smarter Knowledge Gained Figure 1 17 Changing the Size of Multiple Objects You can edit more than one object at a time by using the Marquee Selection tool See Figure 1 17 1 Select the Marquee Selection tool E from the Elements panel 2 Click on the first object that you want to edit then hold down the shift key and then click on the other objects that you want to edit 3 Alternately click and drag the Marquee tool to include multiple items in the drag rectangle 4 Now choose the Edit option from the Menu or continue holding down the shift key and right click
32. YAWL 69 e all blocked tasks and cancelation regions are removed e tasks attached to a hidden input port are replaced by a silent task bearing label tau e the parameters of all configurable multiple instance tasks are restricted according to the configuration settings e all configurable tasks are turned into normal tasks Note that since a task can have multiple input ports e g in the case of an XOR join those input ports that are not hidden will not be replaced with a silent task For more information on how the configuration of hidden ports work please refer to the Process Configuration book chapter of the YAWL Book 3 Figure 1 65 shows the individualized YAWL model for the travel requisition example Task Request for change and its connecting flows have been removed whereas task Check and Update Travel Form has been replaced by a silent task labelled _tau If you inspect this task you will see that it is no longer associated with a decomposition Let s undo the commitment of this configuration to revert its effects This can be done simply by pressing again the toggle button Apply Process Configuration on the tool bar YAWLEditor D Users marcello Desktop Tools Synergia Synergia 0 7 Synergia Examples 0 7 C YAWL models C YAWL travel requisition yawl Specification Net Edit Elements Settings View Help e v G Eee i s s yl New_Net 1
33. a Book e Feel Smarter 1 3 5 Conditions Conditions represent states of the workflow and can be located in between tasks To create a Condition Click on the Add a Condition button Ol in the Elements panel or right click on an empty part of the canvas and choose Condition Go to the Study Privately Net We are going to place a loop Condition after the Read a Book atomic task to determine whether we gained any knowledge from the book We will add the new Condition next Place your Condition in your Net and set the name by right clicking on the Condition and choosing Set Label Call this Condition Knowledge Gained Now link to the Condition to the tasks of the net using flow relations Select the flow relation between the Read a Book atomic task and the Feel Smarter Atomic Task and delete it Create a flow relation from the Read A Book task to the Knowledge Gained condition Create a flow relation from your condition to a task Set the flow relation from the Knowledge Gained condition to Feel Smarter atomic task Create another flow relation from your condition to another task to signify the two possible flows from the condition Before we create our second flow relation from our condition first create another atomic task and call 22 CHAPTER 1 THE EDITOR it Look for An Easier Book Add an XOR join decoration to the Read a Book task with the orient
34. a schema namespace of the variable parameter doco Documentation supplied for the variable parameter usage Whether the variable is input output or both parameter ordering Index of the variable s order compared to the other task variables parameter decomposition Name of the decomposition that contains the variable parameter initialvalue Initial value of the variable if any parameter defaultvalue Default value of the variable if any parameter attribute attribute_name The value of the named extended attribute Table 1 4 Available embedded values for variable level log predicates If the resource service is handling the task some extra embedded values become available for use within workitem level log predicates The resource service will pre parse the log predicate replacing the embedded values it recognises with actual values before passing the log predicate to the engine for final parsing of the workitem level embedded values described above The available embedded values for tasks handled by the resource service can be found in Table 1 5 Other custom services may also provide their own custom embedded values for log predicates consult the documentation of custom services for details participant name Name of the participant handling the work item participant userid Userid of the participant handling the work item participant offeredQueueSize Number of items in the handl
35. ail sender service 1 7 Validating and Saving a Specification At any stage you can validate and or save your specification to a YAWL Engine file yawl To validate your specification 1 Click the Validate button al on the Menu Toolbar or click Specification on the Menu and choose Validate Specification 2 If problems are detected a table listing them will appear at the bottom of the Editor with details of any inconsistencies that would stop the specification from running in the YAWL Engine Figure 1 46 show a specification with no validation problems Figure 1 47 shows an example invalid specification where the Validation Problems table shows that the Bad Task task has no outgoing flow and is not on a path between the input and output conditions af Aa YAWLEditor Users adamsmj Documents research temp myCareer yawl 2 2 am Tala a p E m we ai ma u ae I j ajaja Ela p cla 1 0 0 2 2 2 mw ej C ru O QM eer Ol Study_Privately O Attend_University IL Oa 2 Task Icon Begin My Attend Get ajob Career No Icon Career University Started b 18 Manual b n Automated b B Routing b 7 gi J Plugin Stu dy Privately No design time engine validation problems were found in this specification Left click on the selected net to create a new atomic task Figure 1 46 A valid specification To save your specification to file 1 7 VALIDATING AND SAVING A SPECIFICATION 59 YAWLEdit
36. arameters follow the form name_of_net name_of_variable text and are mapped to a task variable while those for output parameters follow the form name_of_task name_of_variable text and are mapped to a net variable e An Input Usage mode means that the variable requires a value to be mapped into it when its task starts via an input parameter An Output Usage mode means that the variable is required to map a value from it typically to a net level variable when its task completes via an output parameter An Input amp Output Usage mode combines both requirements e Only Net level variables may have a Usage mode of Local which signifies a scope within the net but not external to it Thus sub nets require net level variables with modes other than Local to support data passing to and from their parent nets A root or top level net with variables of type Input Only or Input amp Output will when started request values for those variables from a user via a form before the first task in the net is activated No action is taken for Output modes set for root net variables e Input parameters may only be created for variables of mode types Input Only or Input amp Output e Output parameters may only be created for variables of mode types Output Only or Input amp Output e A single task may map some parameters via XQuery and other parameters via external data gateways as in Figure 1 34 40 CHAPTER 1 THE EDITOR 606 Update Tas
37. ariables of the same XML Schema type and is expected will be the button used in most cases The other button add XQuery of entire element will return the entire XML element of the selected variable which is useful for times when you want to create a complex type expression from individual variable elements Experience with XMLSchema and XQuery are necessary to understand the effects this button will have on runtime YAWL engine state Select the StudentNumber variable from the list of Existing Task Variables Select the Student 1 5 ADDITIONAL SPECIFICATION FEATURES 37 Number net variable then click add XQuery of element s content Figure 1 31 Click Done Create another Task Parameter and map the net SubjectCode to the task variable of the same name using this technique Click Done and Done again ano Update Task Parameter StudentNumber Data Gateway add XQuery o add XQuery of element s content y from element of net variable StudentNumber A add XQuery of entire element XQuery lt StudentNumber gt Attend_University StudentNumber text lt StudentNumber gt populates the task variable StudentNumber y Done Cancel Figure 1 31 Passing a net s StudentNumber value to a Task variable To add an Output Parameter 1 First select the task to add the parameter to ra We will be setting up Output Parameters for the variables that we created in the Adding Upda
38. ask Decomposition Label Enrol Task Decomposition Variables Type Usage string Input amp Output string Input amp Output YAWL Registered Service Detail YAWL Service External Interaction C Automated Set Codelet Done Cancel F Figure 1 29 The Update Task Decomposition dialog for the Enrol task to a single selected task variable Output parameters use an XQuery expression to specify a value that can be passed to a single selected net variable For example if a task is called Lookup Book then an Input Parameter could pass the name of the book to a task variable whereas the Output Parameter of that task may produce the corresponding ISBN for that book To add an Input Parameter 1 Select the task to add the parameter to We will be setting up Input Parameters for the variables that we created in the Adding Updating Task Variables section previously Go to the Attend University Net and select the Enrol task 2 Right click on the task and choose Update Parameters Mappings An Update Parameter dialog box will appear Figure 1 30 ra Update the Parameters for the Enrol task Notice that the dialog in Figure 1 30 lists both this task s CHAPTER 1 THE EDITOR 6056 Update Parameters for Atomic Task Enrol Input Parameters Task Variable Create A Upd ate ap Remove Task Variables Name Type Usage StudentNumber Input amp Outp
39. ation being West Finally create the Flow Relation from the Knowledge Gained condition back to the XOR join of the Read A Book atomic task as per Figure 1 13 6 Validate your specification Validation should fail and report errors as per Figure 1 13 The problem here is that the Study Privately multiple instance composite task needs to have more information specified for it to be valid AAA YAWLEditor Users adamsmj Documents research temp myCareer yawl aj ajalelo o gt Ela Jeje maes epa aja OOO O My Career attend University TC study Privately DOES Look for an L Task Icon Easier Book No Icon gt Manual gt 4 Automated gt E Routing Read a Book Knowledge Feel Smarter Plugin Gained f Composite Task Study Privately 82 id Study Privately 82 the XQuery for param null cannot be equal to null or the empty string The task id Study Privately 82 claims to assign its output to a net variable named null However the containing net does not have such a variable Select a number of net elements to manipulate Figure 1 13 Validation with unfinished Multiple Instance Tasks For setting data detail of multiple instance tasks please see Section 1 5 9 7 Remove the Study Privately multiple instance composite task and replace it with an atomic composite task using the same decomposition and re drawing flows from
40. aximum of 24 x 24 pixels to render properly within editor task boundaries The editor will load user supplied task icons from the location specified for them in the Settings External File Paths dialog see Figure if never specified the location defaults to the directory lt editor_installation_path gt YAWLEditorPlugins TaskIcons and if found adds them into the plugin branch of the task icon tree widget of the editor s palette Sub directories are supported and will form new sub trees of the same name when the plugin sub tree is being created If an icon cannot be found that was previously used for a specification a special broken icon will render in its place as depicted in Figure 1 18 O Figure 1 18 A task specifying an icon that the editor cannot locate 1 5 Additional Specification Features 1 5 1 Cancellation Sets Cancellation Sets allow you to nominate any number of tasks conditions and or flow relations which when they join two tasks directly contain an implicit condition that is not visible on the net for cancellation upon the completion of a specified task That is once a specified task has completed execution in a workflow instance all other net elements within that task s nominated cancellation set if any are deactivated To create a Cancellation Set for a task 1 First select the task that will initiate the Cancellation Set 2 Right click on the task then choose View Cancellation Se
41. bles l to Local Leave the initial value blank Click Done see Figure 1 25 Create another Net Variable with the name SubjectCode and Type string Leave the Initial Value blank and set the Usage to Local usage types will be explained a little later Click Done 32 CHAPTER 1 THE EDITOR BOO Update Net Variable F Log Predicates Name ACA Type string HH Usage Local H Initial Value Done Cancel Figure 1 25 The Net Variable Student Number 4 The Net Variables should now appear in the Update Net Decomposition of Net Attend University dialog box Figure 1 26 06 Update Net Decomposition Attend University Log Predicates ___________ Net Decomposition Label Attend University Net Decomposition Variables Mare Type StudentNumber string Sup ec tLlLoce Done Cancel Figure 1 26 Updated Attend University Net Variables 1 5 ADDITIONAL SPECIFICATION FEATURES 33 1 5 4 Task Decomposition By choosing the Select Task Decomposition option when you right click on a task you have the ability to identify which decomposition is attached to the task A decomposition describes the variables handled by the task and the YAWL Service that will be responsible for performing the work the task represents at runtime Like nets tasks have decompositions where you can specify va
42. ce variable that has been defined to accept a single item from the net level list variable in our case the book variable Accessor Query this query defines the source of the data that needs to be split into multiple 46 CHAPTER 1 THE EDITOR 006 Multiple Atomic Task Verify List Instance Detail Multiple Instance Variable book HH Accessor Query List_Builder MasterList Splitter Query for e in MasterList return lt book gt e lt book gt Instance Query lt order gt Verify list book lt order gt Aggregate Query for d in Verify list return d Result Net Variable MasterList a Done l Cancel Figure 1 40 Set Instance Detail dialog Queries tab for MI task Verify List task instances in most cases as in our example it is a simple XPath expression specifying the net level variable that is being mapped into the MI task and exactly matches the input parameter set for the variable in the Update Parameters dialog In this case it is List_Builder Masterlist note that it is the same XQuery expression as the task s input parameter as shown in Figure 1 39 Splitter Query the splitter is an XQuery expression that is used to take the list variable mapped in and split it into a number of child elements one for each member of the list In natural language the query reads for each element in the accessor variab
43. cification when multiple objects have been selected Left to right they allow you to align selected objects based on e top edges e centres horizontally e bottom edges e left sides e centres vertically e right sides The first selected object is used as the reference to align the other objects to Object Sizes a To increase or decrease the size of an object or objects within your specification select the object s and then use these buttons Cancellation Sets These buttons allow you to include in and or exclude elements from the cancellation set of a task Het Process Configuration tala These buttons allow you to preview left and apply right process configuration settings for a net Zoom Options These buttons allow you to apply zoom functionality to the currently selected net From left to right reset the zoom to the actual size zoom the entire net out zoom the entire net in and zoom into the currently selected net elements 1 2 2 The Menubar This section provides a brief overview of the YAWL Menus located along the top of the YAWL Editor The majority of menu choices are also available via the menu toolbar Specification Net Edit Elements Settings View Help 1 2 THE YAWL EDITOR WORKSPACE 9 Specification In addition to the Specification Maintenance Verification and Analysis toolbar items this menu also contains these sub items e Open Recent show a list of the eight
44. ctor which will allow you to select individual or multiple objects by clicking and dragging the left mouse button Note you cannot create flows arrows between tasks while the Marquee Selector is selected Drag Net Window ES Select this button to drag the visible window of a net around that net 1 2 4 Other Components The Canvas The Canvas is where elements are placed to create and modify a workflow specification 12 CHAPTER 1 THE EDITOR Task Icons Panel This panel shows a set of icons that can be selected and placed on the tasks of your specification to add visual cues that aid in the understanding of your models by others The Editor comes with a standard set of icons and you may also provide your own icons and access them via this panel Note that the icons are grouped for ease of use only you are not limited in how you actually use the icons in your model Any icons displayed have no bearing on how the model executes at runtime Decorations Panel The Decorations panel provides a set of decorator types that may be attached to a task You can select the type of decorator what edge it is to be positioned on the task and choose a colour to use for each decoration Notes and Problem Panel This panel consists of two tabs e On the Notes pane you can add freeform text to accompany the selected task or condition Any text entered is accessible only at design time e The Problems pane will list problems or messages t
45. current configuration settings to the net so that only the configured components remain Check Configuration Correctness analyses the net to check the correctness of configuration set tings requires that the wendy tool is available Edit In addition to the Edit Options toolbar items this menu also contains sub items to Cut Copy and Paste objects to from the canvas Elements This menu contains the Alignment Options Object Sizes and Cancellation Set toolbar item sets You can also set the fill colour for all selected tasks and conditions using this menu 10 CHAPTER 1 THE EDITOR Settings This menu contains the following items e Engine Connection The Editor must connect to a running Engine to obtain a list of the available services that a task can be assigned to amongst other things discussed in later sections This menu item allows you to set the parameters for a connection to the Engine and to proceed with a connection e Resource Service Connection The Editor must connect to a running Resource Service to obtain a list of the available resources that task can be allocated to amongst other things discussed in later sections This menu item allows you to set the parameters for a connection to the Resource Service and to proceed with a connection e Specification Analysis This item will display a dialog where various verification and analysis techniques may be chosen In addition if the wofyawl analysis utility is avai
46. currently doing in the Editor Specification Maintenance This group of buttons provides the standard file options left to right e Create a new specification e Open an existing specification file Specification files will have a yawl extension or sometimes a xml extension if they are an engine file created with a pre 2 0 Editor version e Import a specification file created with a pre 2 0 version of the Editor These files have a ywl extension e Save the currently loaded specification to file For newly created specifications this behaves the same as Save As e Save As a new file name e Close the loaded specification If there are any unsaved changes you will be prompted to save the file first before closing Specification Verification amp Analysis The first of these two buttons allows you to validate your specification against YAWL syntax and semantics while the second allows you to analyse your specification for deadlocks and other issues Net Maintenance Each workflow specification consists of one or more nets You can use these buttons to add a new Net to or remove an existing Net from your specification Edit Options ale s This group of buttons provides the standard Undo and Redo options as well as the option to delete the currently selected object s 8 CHAPTER 1 THE EDITOR Alignment Options HOSE These buttons can be used to assist with the alignment of objects within your spe
47. d in the menu item Settings gt External File Paths Settings There are Wendy TO CHAPTER 1 THE EDITOR distributions for Windows 32bit MacOS and Linux available for download from the YAWL SourceForge project The Configuration Correctness Checker can be enabled at any time from the menu Net gt Process Config uration This will invoke Wendy to analyse the current model and the output from this tool will appear in a pop up window see Figure This process may take some time depending on your machine s character istics and on the degree of parallelism of your YAWL model i e how many combinations of tasks there exist that can be executed in interleaved parallelism However you only have to run this process once once you have completed the design of your process and are ready to configure it You can also interrupt this process at any time by closing the window Check Configuration Correctness Analysing Net Completed wendy 4300000 inner markings a wendy LoLA is done 324 sec wendy closed and deleted temporary file wendy a08116 wendy stored 4325128 inner markings 9480 final 1323456 bad 2879275 inevitable deadlocks wendy 7578 knowledges 100000 edges wendy stored 12408 knowledges 164198 edges 4 sec wendy 11073 knowledges reachable wendy netis controllable YES wendy writing service automaton to file temp sa wendy closed file temp sa
48. d when data values are assigned to and from each net and task variable A log predicate can contain any text and may also contain embedded values describing current values for certain aspects of the process Embedded values take the form keyword and different sets of values are available depending on whether the log predicate refers to a net task or variable The available embedded values for a net level log predicate can be seen in Table 1 2 while those at the task level are listed in Table 1 3 and those at the variable level are listed in Table 1 4 Current date and time Current date Current time Name of the net Name of the specification that contains the net decomp name decomp spec name Names of any input parameters for the net decomp outputs Names of any output parameters for the net decomp doco Documentation supplied for the net decomp attribute attribute_name The value of the named extended attribute ecomp inputs d Table 1 2 Available embedded values for net level log predicates Current date and time Current date Current time spec name spec version spec key task id task name task doco task decomposition name item id item handlingservice name item handlingservice uri item handlingservice doco item codelet item customform item enabledtime item firedtime item startedtime item status it
49. der MasterList book Update Remove Task Variables Mame Type Usage book BookOrder Input amp Output Net Variables Name Type MasterList BookList Output Parameters XQuery Net Variable Create lt order gt Verify list book lt order gt MasterList Update Remove Figure 1 39 Update Parameter Mapping dialog for MI task Verify List e Right click on the Verify List MI task and choose Set Instance Detail from the popup menu On the Bounds tab page set minimum instance to 1 maximum instances to 20 continuation threshold to 5 and static instance creation type These settings mean that between 1 and 20 task instances will by started from this MI task at runtime depending on the number of book orders in the book list the MI task will complete when 5 instances complete or all complete if less than 5 were started and new instances may not be dynamically started after task execution begins Now click the Queries tab page It is here that we will specify how the BookOrders contained in the MasterList variable will be split into individual task variable instances and how those instance variables are aggregated back into the MasterList on completion Figure 1 40 shows the Queries tab page for the Verify List MI task There are six parts to this dialog four requiring XQueries and two variable settings Multiple Instance Variable this specifies the task instan
50. dy Task and delete it We will add in the new Multiple Composite task next Place your Multiple Composite Task in your Net Reconnect the Flow Relations from Begin My Career to the new Multiple Composite Task and from the new Multiple Composite Task to Get a Job You will now need to set the parameters of the Multiple Composite Task in the same manner as those set previously for the Multiple Atomic Task Right click on the task and choose Set Instance Detail Set the Minimum Instances to 5 the Maximum Instances to 100 the Continuation Threshold to 50 and the Instance Creation type to Static 1 3 CREATING YOUR FIRST SPECIFICATION 21 Click Done Create a new Net by clicking on the Create a new Net button Ej on the Menu Toolbar or click on Net in the Menu and choose Create Net Give the new Net a name by clicking on the Net Menu and choosing Update Net Detail We are going to call this new Net Study Privately Return to your original Net and right click on your Multiple Composite Task and choose Unfold to Net You will then be given a drop down list with all the Nets Available choose the Net for this task to initiate and then click Done Choose Study Privately You can now complete your new Study Privately Net represented by your Composite Task Create the following Atomic Tasks in order and then link them with Flow Relations as per Figure 1 13 e Read
51. e against schema if true Insert given text above the field Insert given text below the field Render a text area instead of a text field text fields only A tip to show when the mouse hovers over the field Total number of digits expected numeric values only Normalise whitespace in the given value Table 1 7 Default variable level extended attributes auto generated message yellow mandatory white optional false black browser default 12 point None none false false none left none left left variable name undefined false false undefined undefined undefined undefined undefined undefined false undefined false false undefined undefined auto generated tooltip undefined undefined 18 CHAPTER 1 THE EDITOR 606 Update Task Decomposition Enrol Standard Log Predicates Name Value background alt color background color o HOOFFCC font color font name Baskerville font size 12 font style None HH 31 header font color header font name Courier New EA header font size 16 header font style Bold a hideHeader 4 justify left label page background color page background image readOnly ral gt title I Done Cancel Figure 1 72 Default decomposition level extended attributes In that folder the Editor will look for a file named DecompositionProperties no extension for decomposition level properties and a file named VariableProperties no
52. e decomposition is of BookOrder type in our data definition we have defined the BookList type being comprised of a number of BookOrder type elements so what has been defined in this decomposition is a mapping of a single BookOrder to each task instance that will be created when the MI task is executed e The mapping of input and output parameters for MI tasks is done a little differently to atomic single instance tasks and involves a two stage process Open the Update Parameter Mapping dialog for the MI task Verify List and add the input and output parameter mappings as seen in Figure 1 39 Notice that the input parameter maps the entire net level variable MasterList to book a single task level BookOrder variable while the output parameter maps the contents of the book variable wrapped ADDITIONAL SPECIFICATION FEATURES 45 in order tags back to the net level MasterList These kinds of mappings would be invalid for a single instance task but here we need to define a mapping that on input takes a net level list assigns each member of the list to a task instance and on output takes each task instance s variable and maps it back to the net level list The intermediary steps that allow this mapping to occur is done in the second stage of the mapping process 606 Update Parameters for Multiple Atomic Task Verify List Input Parameters XQuery Task Variable Create List Buil
53. e performed via the Settings menu To set the Resource Service connection details 1 Click on the Settings menu and choose the Resource Service Connection item 2 From the resulting dialog Figure 1 45 accept the default values or enter the following engine details e YAWL Engine URI e Administrator s User Name e Administrator s Password Bon Resource Service Connection Settings Resource Service URI http localhost 8080 resourceService gateway User Name admin A Test Connection Password Successfully connected to a running resource service Done Cancel A Figure 1 45 Specifying the Resource Service connection The Resource Engine value is set by default to a locally installed Resource Service http localhost 8080 resourceService gateway but should be changed if the Engine is installed remotely The User Name and Password have the following case sensitive defaults but can be changed via the Client Applications web form Section e user name editor e password yEditor 1 6 3 Connecting a Decomposition to a registered YAWL Service You can use task decompositions within your workflow to make a connection to custom YAWL services that have been registered with a running engine By associating a task decomposition with a custom service all task instances based on that decomposition will be passed to the custom service at runtime for processing that is the custom service is respon
54. ed Geek that has two separate sub components Name and Salary of type string and double respectively Types called Book and Booklist are created in the same way As depicted in Figure 1 23 the new data type Geek is available to choose from the list of available types when creating a task or net variable Variables with a usage of Local can have initial values specified for them as depicted in the same figure As with the data type definition dialog parse errors will be listed when the initial value text is red 30 CHAPTER 1 THE EDITOR 606 Update Data Type Definitions aia Bie lt xs schema xmlns xse http www w3 org 2001 XMLSchema gt lt xs icomplexType name Geek gt lt XS t Sequence gt lt xs element name Name type xsistring gt lt xs element name Salary type xs double gt ZES i Sequence gt lt xs complexType gt lt xs icomplexType name Book gt lt KS tsequence gt lt xs element name Title type xsistring gt lt xs element name Autor type xs istring gt lt f KS i Sequence gt lt xs complexType gt lt xs icomplexType name Booklist gt lt S i sequence maxOccurs 5 gt lt xs element name Book type Boo gt lt S sequence gt lt xs complexType gt lt xs achema gt Invalid ln 19 col 40 sre resolve Cannot resolve the name Boo i Done Cancel 0 a Figure 1 22 When the data type definition
55. em timer status item timer expiry item attribute attribute_name expression xquery_expression y Name of the specification containing this task Version of the specification containing this task Internal identifier of the specification containing this task Runtime identifier of the task Name of the task Documentation supplied for the task Name of the net that contains the task Runtime identifier of the work item Name of the service responsible for the work item URI of the service responsible for the work item Documentation supplied for the service responsible for the work item Name of the codelet to be executed for the work item if any URI of the custom form to be displayed for the work item if any Date and time the work item was enabled Date and time the work item was fired Date and time the work item was started Current status of the work item Current status of timer set for the work item if any Expiration time of timer set for the work item if any The value of the named extended attribute The evaluated value of the XQuery expression specified The expression may reference work item variable data values Table 1 3 Available embedded values for work item level log predicates 1 14 CONFIGURABLE LOGGING 13 Current date and time Current date Current time parameter name Name of the variable parameter datatype Data type of the variable parameter namespace Dat
56. ent YAWL Process Editor a ual process 10del Workflow API calls specification YAWL Runtime Environment ASA XML over HTTP Figure 1 1 The YAWL Components In this chapter this icon indicates a hands on method or instruction 1 1 Launching the YAWL Editor The Editor is installed along with the other YAWL System components using any of the installers described in Chapter It can also be installed manually by downloading the latest version from the YAWL SourceForge website http sourceforge net projects yawl Be sure that the version number of the Editor you are using matches the version of YAWL installed The YAWL Editor is distributed as a Java Archive jar Double click on the YAWLEditor2 1 jar file to start 5 6 CHAPTER 1 THE EDITOR the application where supported The YAWL Editor can also be started from a command line or Terminal prompt java jar YAWLEditor2 1 jar 1 2 The YAWL Editor Workspace The first time you start the YAWL Editor you will be presented with a blank canvas and a prompt in the Status Bar advising you to open or create specification to begin Before you create your first specification let us take a brief tour of the Editor s workspace and the elements within the use of each element is fully described in later sections The workspace is shown
57. f the two tasks Go To University or Do Private Study will be followed XOR Split How that choice is made will be explained a little later Get a Job will become available after the completion of the task selected at the point of the XOR split Composite Tasks 1 Composite tasks are placeholders for other sub nets That is you can create another workflow in a separate Net which is represented in the first net by the composite task When a composite task is activated control branches to the sub net when the sub net completes control passes back to the parent net 1 3 CREATING YOUR FIRST SPECIFICATION 17 Career Started Go to University Begin My Career Do Private Study Figure 1 8 XOR Split and Join 2 To create a Composite Task click on the Composite Task button al in the Elements panel or right click on an empty part of the canvas and choose Composite Task We are going to replace our existing Go to University Atomic Task with a Composite Task so click on the Go to University Atomic Task and click the trash bin on the toolbar or press the Delete key on the keyboard We will add in the new composite task next 3 Place your Composite Task in your Net Tip use the arrow keys on your keyboard to move adjust the task to the desired location Reconnect the Flow Relations from Begin My Career to the new Composite Task and from new Composite Task to Get
58. gnated as manual by default but can be set as automated by right clicking on it and selecting the Task Decomposition Detail dialog then ticking the Automated checkbox in the External Interaction section see Figure 1 29 When the Automated checkbox is checked the option Manage Resourcing in the task s right click menu will be disabled since human resources are not required for automated tasks Data manipulation can be achieved by using the task s variables and their Input and Output Parameters Parameters are generally used to copy the content of a net variable to a task variable and back again But 58 CHAPTER 1 THE EDITOR parameters may also contain an XQuery expression that uses static values or the values of other variables to copy data between net variables and task variables Figure 1 52 shows an simple example of copying from expression where the literal true is copied onto the net variable PO_timedout after choosing the from expression radio button This choice is only available for automated tasks and any task variables used in the XQuery expression itself must be declared as Input amp Output usage types 658 Update Net Parameter PO_timedout P 3 5 7 de trom element of task variable i add XQuery of element s content E i from expression 2 add XQuery of entire element gt xQuery lt PO_timedout gt true lt PO_timedout gt populates the net variable PO_timedout KA Create Done Cancel
59. graph of an unbounded analysis net slow Figure 1 51 Verification using wofYAWL 1 9 Automated task Any atomic task in YAWL that is associated with the Resource Service i e the default association if the task is not explicitly associated with another service can have its decomposition defined as manual or automated A task with a manual decomposition is a task that is intended to be executed by a human resource e g a participant in the Resource Service s organisational model A task with an automated decomposition is a task that is not offered to any resource but is executed by the system This type of task can be used to manipulate the content of net variables from simple data assignments to complex reports generation Alternately it may be associated with a codelet a discrete piece of code that is executed optionally using the input variables of the task and assigning any results to the chosen output variables of the task Both task types are handled by the Resource Service but the behaviour of an automated task differs as follows e on enablement it is automatically checked out of the engine thus having priority over manual tasks in a deferred choice and its input parameters are parsed e if a codelet has been specified it will be executed it using the task s variables as required then e it is automatically checked in and its output variables are mapped back to the corresponding net variables A task is desi
60. grey filled task see Figure 1 20 Add the selected tasks and flow relations to the cancellation set 5 Once you have established the cancellation set you can right click on the cancellable task and reselect View Cancellation Set to toggle off the cancellation set view Notes about Cancellation Sets e In the example in Figure 1 20 notice that there is an AND split decorating the Get Book Details task but the Pay task has an XOR join This is because we know that when one of the Order tasks completes the other two will be cancelled so only one incoming flow to the Pay task will activate Since we want the process to complete we must add the join type that will activate the task when a single incoming flow activates the XOR join If an AND join had been used here it would wait until all three incoming flows were activated which in this case is never going to happen and would result in the deadlock of the workflow instance However without the careful setting of cancellation sets for all three intermediate tasks the net would represent an example of an unsound net which basically means the net may complete while there were still active tasks within it Great care needs to be taken when mixing split and join types and when defining cancellation sets so that the execution of the net behaves precisely as intended e A Cancellation Set that has been created will remain in the specification regardless of whether
61. hat may occur while you are building your model when you validate it or when you analyse it Status Bar The Status Bar consists of three parts e On the left are two icons that indicate whether there are currently valid connections to the Engine and the Resource Service required for certain design activities discussed later in this chapter A connection will show a green indicator a disconnection as a red indicator e Next there is a status message area that provides useful contextual hints throughout the creation of your specification e On the right is a progress bar which shows the progress of various events at different times 1 3 Creating Your First Specification Overview This section will lead you through the process of creating a YAWL specification from beginning to end through a series of brief lessons following a scenario You can either follow all the instructions including the scenario provided from beginning to end or skip straight to the section that you are interested in and follow the instructions Look for the student icon next to the instructions for specific details of the scenario The Scenario The scenario that we will be following throughout this section is the workflow of a student who has just completed their secondary study and is now looking to start their career The scenario will follow the path of a student who either enrols in a University to complete their tertiary education or undertakes priva
62. he Starting Net Note that the starting net has an input condition symbol gt in its title tab and in the View menu list All sub nets have a composite task symbol o in their title tab and in the View menu list 1 4 Changing the Appearance of Your Specification 1 4 1 Changing Flow Relations Bends and Curves You can control and improve the look of the flows between tasks by adding bends in them Go to the Study Privately Net Right click on the position in the flow where you want to add a bend which will be denoted by a small blue square in the Flow A popup menu will appear allowing you to add and remove bends as well as change the line style of the flow ra Create a bend somewhere towards the middle of the flow going from the Knowledge Gained condition to 24 CHAPTER 1 THE EDITOR the Look for an Easier Book atomic task Then left click on the bend marker created and drag it out to a more desirable location You can add as many bends to a flow as you like Repeat the process for the flow between Look For an Easier Book and Read A Book tasks see Fig ure 1 16 Relocation You can reconnect flow relations to other elements of a net or different points on the same element by se lecting the flow and dragging one of its connecting ends from one net element to another If a connection is possible at some other element connection points will become visible as described earlier
63. he work item i e to allocate the work item to themselves If System allocation is chosen in Step 4 we can specify how work items will be allocated to a participant by the System 60 CHAPTER 1 THE EDITOR Sone Manage Resourcing Wizard for Atomic Task Determine Credit Requirements Step 1 Interaction Points Each task passes through three interaction or decision points before a participant begins working on it For each of the interaction points below please specify whether the task is to be handled by the System dynamically based on the settings chosen later in this wizard or by the User manually by a participant or an administrator when the task is executed Offer The task is made available to a number of participants User fa System Allocate The task is assigned to a single participant User System Start Work begins on the task User System lt Back gt Next Finish Figure 1 54 Step 1 of the resource management wizard If we choose that work items are to be Started by the User and not by the System then the user will choose to manually start working on the work item at a time of their choosing If System starting is chosen the work item once it is allocated to the participant will be immediately started Step 2 In Step 2 shown in Figure 1 55 we can select an initial set of resources called the distribution set that will be offered work items of the selected task at ru
64. heck whether all OR joins are immutable Another correctness notion is that of irreducible cancellation regions Here it is checked whether certain conditions or tasks can be removed from a cancellation region as they will never contain a token or will never be active when the associated cancellation task executes The YAWL editor offers two different approaches to automated verification One approach 6 is based on the theory of Reset nets this is built into the Editor The other approach 5 uses Petri net theory and in particular the concept of transition invariants For this latter approach the program wofYAWL is to be used the executable of this program should be put in the same directory as the Editor under the name wofyawl0 4 exe These approaches are different in that there are workflow specifications where one of them can pick up an error which the other approach cannot By choosing Configure Specification Analysis under the Tools menu in the Editor one can choose what type of verification the YAWL editor needs to perform As some forms of verification may require quite a bit of time it is important to choose the right approach and generally speaking it is probably best not to verify every intermediate version of a specification The screen shot shown in Figure 1 50 shows the options one can choose for the analysis based on Reset nets This form of analysis supports the use of reduction rules YAWL reduction rules can be applied t
65. if true false justify Justify text in text fields left label Label text for form header task name page background color The background color of the page white page background image The background image url for the page none readOnly Field values can t be modified if true false title Title of form Edit Work Item ttem case id Table 1 6 Default decomposition level extended attributes e Those attributes marked with an asterisk in Table 1 7 mirror XML Schema facets that may be set for values as part of the type definition for a field If a extended attribute facet has a value and the type definition also has a value for the facet the extended attribute value takes precedence Note that not all facets make sense for all data types where a value is set for an extended attribute that mirrors a facet and the field in question does not support that facet then the value is ignored For example the facets minExclusive minInclusive maxExclusive and maxInclusive apply only to numeric fields Please refer to an XML Schema reference for more information about facets and their application to different data types for example http www w3 org TR xmlschema 2 rf facets and http www w3school1s com schema schema_facets asp e Values for the text above text below and label attributes may include embedded XQuery XPath ex pressions that reference the work item s data See the Section 1 15 3 for examples e The readOnly a
66. in identifying unreachable tasks in the specification potential deadlocks and possible unfinished work in completed workflow cases wi Keep Analysis progess dialog open when Analysis completes Done Cancel Figure 1 49 Configure Specification Analysis dialog Ar Analysing Specification Completed Immediate Successors 29 Immediate Successors 24 Immediate Successors 19 Immediate Successors 14 Immediate Successors Y Immediate Successors 5 Immediate Successors 2 Reachability Set size 322 Duration 1450 millisecs Eil Keep open when analysis completes Close Figure 1 50 Configure Specification Analysis dialog If the optional YAWL specification analysis utility wofyawl exe is supplied in the same directory as the Editor an extra tab entitled WofYAWL Analysis will be enabled in this dialog allowing more analysis 56 CHAPTER 1 THE EDITOR options than those supplied by default The utility must be compiled for specific architectures The current version of the Editor needs version 0 4 of the utility 1 8 1 Verification and Analysis Explained This section provides a brief overview of verification in YAWL Verification is concerned with the design time detection of certain undesirable characteristics in process models Extensive research has been conducted in the area of workflow verification One of the pioneers of this work is Wil va
67. ing participants offered queue participant allocatedQueueSize Number of items in the handling participants allocated queue participant startedQueueSsize Number of items in the handling participants started queue participant suspendedQueueSize Number of items in the handling participants suspended queue resource initiator offer Whether the workitem s offer interaction was initiated by the system or by a user resource initiator allocate Whether the workitem s allocate interaction was initiated by the system or by a user resource initiator start Whether the workitem s start interaction was initiated by the system or by a user resource offerset A comma separated list of the names of all participants the workitem was offered to resource piler The name of the participant piling the workitem if any resource deallocators A comma separated list of the names of all participants who have deallocated the workitem resource allocator Name of the system based allocation algorithm used to allocate the workitem resource roles A comma separated list of the names of all roles the workitem was offered to resource dynParams A comma separated list of the names of all dynamic parameters used in the offer set evaluation for the workitem resource filters A comma separated list of the names of all filters used in the offer set evaluation for the workitem resource constraints A comma separated list of the names of al
68. instance A role is essentially a set of participants 1 10 RESOURCE MANAGEMENT MANUAL TASK 61 ODO Manage Resourcing Wizard for Atomic Task Raise purchase order Step 2 System Offer A task may be offered to one or more participants and or roles Please choose below the participant s and or role s the task is to be offered to One or more net parameters if available may also be chosen below These are parameters that at runtime may contain either a userid set the Refers To value to Participant or a role name set to Role that is to be included in the set of resources the task is offered to Participants Roles Net Parameters Kay Adams ka Junior Supply Officer rn Name Refers to Billy Van Arsdale bva Order Fulfilment Manager Momo Barone mb Senior Credit Officer Emilio Barzini eb Senior Finance Officer Peter Clemenza pc Senior Supply Officer Stefano Clemenza sca Shipment Planner Don Vito Corleone dvc Supply Admin Officer o Fredo Corleone fc Warehouse Admin Officer Mama Corleone mac Y Warehouse Officer Y lt Back gt Next Finish Figure 1 55 Step 2 of the resource management wizard a0 0A Manage Resourcing Wizard for Atomic Task Raise purchase order Step 3 System Offer Filters and Constraints Filters The resource set specified in Step 2 can be filtered and or constrained so that only those resources that meet
69. ion xquery help string 80 CHAPTER 1 THE EDITOR mode enumeration normal final pending refresh xquery showDetails boolean Only those values that are changed from their defaults will be saved to the specification file For all types ex cept enumeration the default value is considered to be an empty field For enumerations the first listed value is considered the default To denote an empty value as the first in an enumerated list list the enumeration like this example i e with no first value mode enumeration normal final pending Figure 1 74 shows the rendered list of attributes for the above property file note that they are listed under neath the default attributes Note that attributes can only be specified through property files and not via the above dialogs BOB Update Task Decomposition Enrol Standard Log Predicates Name Value font style None Ej header font color header font name Courier New header font size 16 header font style Bold hideHeader H ust wo B label page background color page background image readOnly ra title description help made normal refresh showDetails p Done Cancel E Figure 1 74 User defined extended attributes displayed in the Extended Attributes tab 1 15 EXTENDED ATTRIBUTES Sl 1 15 3 Extended Attribute Example To show a small sample of what can be done with extended attributes a simple specification called Eter nalQuestion
70. is invalid 1 5 3 Net Decomposition Detail Net Variables You can add variables to a net to store information relating to that net that tasks within the net may need to read or update To add a variable to a Net 1 Choose Update Net Detail from the Net Menu ra We will be setting up Net variables in the Attend University net Go to the Attend University Net and choose Update Net Detail from the Net Menu 2 An Update Net Decomposition dialog box will appear see Figure 1 24 Click on the Create button This will show an Update Net Variable dialog box see Figure 1 25 3 Enter the Name of your variable choose the Type and intended Usage of the variable from those listed then click Done then Done again to close the Net Decomposition dialog ra Enter StudentNumber for the name of the variable leave the type as string and set the Usage type 1 5 ADDITIONAL SPECIFICATION FEATURES BOO Update Net Variable Log Predicates Name testGeek Type Geek HH Usage Local HH Initial Value eyame gt John Frank lt Name gt lt Salary gt 10000 00 lt 5alary gt Done Cancel Figure 1 23 A Geek net variable with a valid initial value Update Net Decomposition Attend University Log Predicates Net Decomposition Label MPA Net Decomposition Variables Name Type Usage Create Update Remove Figure 1 24 Updating Attend University Net Varia
71. k Parameter StudentNumber Mame SimpleExternalDBGatewayImpl populates the task variable StudentNumber KH Create Done Cancel Figure 1 33 The Data Gateway tab 1 5 8 Flow Detail When dealing with tasks that have XOR and OR splits we need some way of defining which flows should be activated at runtime This is achieved by associating a boolean XQuery expression with each flow At runtime the flow expressions are evaluated and e if the split type is an OR split each flow that has an expression that evaluates to true will be executed e if the split type is an XOR split the first listed flow that has an expression that evaluates to true will be executed Since it is possible that all flow expressions evaluate to false XOR and OR splits must nominate a default flow which will activate if all of the other flow expressions evaluate to false to ensure that the workflow does not deadlock i e is not blocked at that point from proceeding and eventually completing Default flows are defined by prioritising the order in which the various flows of a split are evaluated the one prioritised last in the order becomes the default flow To update the flow detail of a task that has a split right click on the task and choose Update Flow Detail The Flow Detail dialog appears which list the flows coming out of the split and each flow s corresponding Predicate or flow expression The arrowed butt
72. ktop Tools Synergia Synergia 0 7 Synergia Examples 0 7 C YAWL models C YAWL travel requisition yawl Specification Net Edit Elements Settings View Help amp B v e aja gt Y E a El A f J Task Icon No Icon Manual Approve o EL Automated Prepare Travel Form a Travel Form Admin F Employer y Plugin Arrange PR J Submit Travel N Travel Form Insurance w for Approval Reject Travel Form Prepare Es Check and Travel Form Update Secretary aN _ Travel Form Request for change Q909 Use the palette toolbar to edit the selected net Figure 1 68 Preview of the configuration after blocking the input port of task Check and Update Travel Form 12 CHAPTER 1 THE EDITOR 1 14 Configurable Logging The YAWL process logging framework keeps a record of all aspects of each process execution including all control flow resourcing and data aspects which can later be analysed As part of the logging framework provision is made for configurable logging that is the ability to log messages known as Log Predicates along with process data during process execution Log Predicates may be defined for each process that will be logged at the start and completion of each net at the start and completion of each work item an
73. l constraints used in the offer set evaluation for the workitem Table 1 5 Additional resourcing embedded values for work item level log predicates Log predicates are optional and so may be left empty if desired To add a net level log predicate open 74 CHAPTER 1 THE EDITOR the Update Net Decomposition dialog via the menu Net Update Net Detail and click on the Log Predicate tab Figure 1 69 To add a task level log predicate open the Update Task Decomposition dialog right click on the task then choose Task Decomposition Detail from the popup menu and click on the Log Predicate tab Figure 1 70 To add a variable level log predicate open either of the previous two dialogs depending on whether it is a net level or task level variable then either create an new variable via the Create button or choose an existing variable from those listed and click the Update button and click on the Log Predicate tab Figure 1 71 0 8 Update Net Decomposition Attend Universite Standard On Start An instance of decomp spec name is started now On Completion Net S decomp name of specification decomp spec name completed now Done Cancel Figure 1 69 Entering net level log predicates 1 15 Extended Attributes The Editor offers a means for defining extended attributes to be associated with task decompositions and variables There are a default set of attributes supplied for task deco
74. lable the configuration dialog will allow process designers to configure and use wofyawl for additional specification analysis e Process Configuration This item will display a dialog where the desired process configuration settings may be chosen e External File Paths This item will display a dialog where the disk locations of the following components may be specified User defined extended attributes for decompositions User defined extended attributes for variables User supplied icons for tasks the WofYAWL tool for specification analysis the Wendy tool for process configuration View You can use this menu to toggle e Tooltips which provide useful hints when your mouse is positioned over various items e Anti aliasing of graphical components and e Grid on the canvas background useful for aligning objects visually This menu also provides options to set the font size used for element labels the default background colour for nets and the default background colour for elements i e tasks and conditions Finally it shows a list of all the nets of the loaded specification allowing the selection of one from those available for editing Help The Help Menu provides an About the Editor dialog describing components used in the editor s construc tion a list of source code contributors and the version and build date of the Editor in use 1 2 3 Workflow Elements and Tool
75. lation set may not have started when the owner task of the set completes then cancelling those tasks will have no effect it is their preceding conditions that have control and so they are the elements that must be cancelled By including both tasks and their preceding conditions we are ensuring that the desired cancellation will occur regardless of whether the tasks in the set are currently executing or not To remove an element from a task s Cancellation Set 1 First make sure you have the View Cancellation Set option ticked for the task If it isn t ticked select the task that has the Cancellation Set right click then choose View Cancellation Set Select the element for removal Click on the Remove Selected Items from Visible Cancellation Set button FA on the Menu Toolbar 1 5 2 Data Type Definitions YAWL uses XML Schema to define data documents that are passed from net to task and back during the life of a workflow instance There are over 40 simple XML Schema data types string integer boolean etc all of which are supported by YAWL User defined data types are also supported by allowing for the definition of XML Schema complex types which are added to a specification and then may be used to define variables based on those types To define a new complex type for a specification 1 5 ADDITIONAL SPECIFICATION FEATURES 29 1 Select Update Data Type Definitions from the Specification Menu 2
76. le return that element In our example the XQuery is for e in MasterList return lt book gt e lt book gt The e part is a query variable all query variables start with a sign followed by one or more characters e is a convention for a loop variable but other names are of course allowed The return value for each e in our query would start and end with order tags since our variable is called book we have to replace the order tags with book tags so the return value of our XQuery is the contents of the order e but surrounded by book tags The final result is 1 5 ADDITIONAL SPECIFICATION FEATURES 47 a number of book values each corresponding to one order element in MasterList Instance Query this query defines how the book variable within each task instance should be formatted prior to being mapped back to the net level MasterList Like the splitter query above we need to replace the surrounding book tags with order tags the contents of the element being the contents of the book variable Verify_list book Notice also that this query exactly matches the task s output parameter in Figure 1 39 Aggregate Query puts all the instance query results into a list in this case a list of order elements ready for mapping back to the net level variable The aggregate query will look exactly like this in most cases except that
77. mic Task as shown in Figure 1 5 by finding the flow connectors that appear as small blue boxes as you hover your mouse over the sides of the objects Hold the left mouse button down over a flow connector and draw a line by dragging the mouse from the flow connector on the Input Condition to the one on the Atomic Task which will appear when the mouse hovers over the edges of the task The editor will only show a connection point if it is valid to draw a flow connection between the objects The directed arc arrow between two objects is referred to as a flow Ormi Begin My Career Figure 1 5 An established flow relation relation or most often simply a flow it shows the flow of execution from one object in the net to the next That s it Your Atomic Task is set Repeat the process for the following Atomic Tasks in order Go to University Get A Job Career Started Link the Career Started task to the Output Condition the m symbol as per Figure 1 6 7 Finally check the validity of specification by clicking on the Validate Specification button al in the Menu Toolbar or click on Specification in the Menu and choose Validate Specification If all things are going to plan then you should receive a confirmation saying that there were no errors detected Task Indicators Task indicators are mini icons that appear across the top of a task to provide a visual cue regarding settings that have been applied to the task An e
78. mpositions and a default set for task variables the values of which may be set at design time at runtime the values for the most part will effect the display parameters of the dynamic form generated by the Resource Service s default worklist handler for the work item Additionally designers may add their own extended attribute definitions to the Editor at design time for runtime interpretation via custom classes and services That is the Resource Service will interpret and act on any values set for the default extended attributes while the effects of values set for user defined extended attributes are defined by developers of custom services See Section 1 15 2 for information on defining your own extended attributes 1 15 1 The Default Extended Attributes Table 1 6 lists the default extended attributes for decompositions For the most part the attributes affect the work item level of the dynamic form displayed i e the form itself Note that where an variable level attribute of the same name as a decomposition level attribute exists the variable level attribute takes precedence Table 1 7 lists the default variable level extended attributes For the most part the attributes affect a single variable field on the dynamic form displayed Notes about extended attributes 1 15 EXTENDED ATTRIBUTES 19 808 Update Task Decomposition Enrol Standard Extended Attributes On Start Started work item with id S item id
79. n der Aalst He formally defined the notion of soundness as a correctness notion for workflow nets This class of Petri nets forms a predecessor of YAWL which does not support OR splits joins Multiple Instance Tasks and cancellation regions Informally speaking a workflow is sound iff 1 e The net has the option to complete That means that from every reachable state the final state where there is a single token in the output condition can be reached e The net has proper completion This means that when the output condition is marked there are no other tokens anywhere else in the net e The net has no dead tasks These are tasks that cannot be executed in any scenario For YAWL the notion of weak soundness was introduced as it can be theoretically proven that soundness is not decidable 6 For a finite state space we can simply try and check all reachable states but this is obviously not possible when this state space is very large or infinite In those cases we can check whether it is possible to reach the final state from the initial state Hence does a scenario exist where we reach the final state The richer concepts offered by YAWL also introduce additional correctness notions For example an analyst may have used an OR join where an XOR join or an AND join could have been used This is not desirable for computational reasons but also because it makes the process model harder to understand Hence the YAWL environment will c
80. nated default flow if none of the other flow conditions evaluate to true e OR split The task may have a number of outgoing flows each with an associated condition when the task completes it will activate each outgoing flow that has its condition evaluate to true or the designated default flow if none of the other flows evaluate to true By adding a join to a task you are specifying at what point the task will become available for execution through the completion of one or more preceding tasks flowing into it depending on the type of join Below are possible choices for a task s join decorator 16 CHAPTER 1 THE EDITOR No join The task has no join decorator and so will have exactly one incoming flow AND join The task will activate only after each and every incoming flow is activated through the completion of the task at the other end of each flow XOR join The task will activate as soon as one incoming flow is activated through the completion of the task at the other end of the flow OR join The task will activate only after each and every incoming flow that can possibly be activated has activated Basically this means the completion of each and every task at the other end of a flow leading into the OR join that has started or may possibly start at some future time More on the OR join in later sections For more detailed information on join and split types please consult the YAWL technical papers on the YAWL website
81. nces created have completed or if the number of instance created exceeds the Continuation Threshold the number specified for the Continu ation Threshold have completed the multiple instance task itself will be considered complete and will trigger relevant outgoing flow relations from this task Set the Continuation Threshold to 50 Click Done With the values set in the scenario it has been specified that the Do Private Study task can have a maximum of 100 instances created a minimum of five instances will be created and once 50 instances or all those started if less than 50 have completed the outgoing flow relation to Get A Job will trigger We will revisit the setting of parameters for multiple instance tasks in particular the details of the Queries tab of the Multiple Instance Detail dialog in Section 1 5 9 after the basics of queries have been introduced 1 3 4 Multiple Instance Composite Tasks Multiple Instance Composite Tasks allow you to run multiple instances of the sub net represented by a multiple composite task concurrently To create a Multiple Composite Task Click on the Add Multiple Composite Task button in the Elements panel or right click in an empty part of the canvas and choose Multiple Composite Task Go to the My Career Net We are going to replace our existing Do Private Study Multiple Instance Task with a Multiple Composite task so click on the Do Private Stu
82. nd University sub net 1 3 3 Multiple Instance Atomic Tasks Multiple Instance Atomic Tasks MI Tasks allow you to run multiple instances of a task concurrently To create a Multiple Instance Atomic Task Click on the Add Multiple Instance Atomic Task button a in the Elements panel or right click in an empty part of the canvas and choose Multiple Atomic Task Go back to the My Career Net We are going to replace our existing Do Private Study Atomic Task with a Multiple Instance Atomic task so click on the Do Private Study Atomic Task and delete it We will add in the new Multiple Instance Atomic task next Place your Multiple Instance Atomic Task in your Net and set the name of this task by right clicking on the task and choosing Select Task Decomposition Give this task the same decomposition as before by selecting Do Private Study from the drop down list Reconnect the flow relations from Begin My Career to Do Private Study and from Do Private Study to Get A Job as per Figure 1 11 You will now need to set the parameters of the MI Task which being multiple instance needs a few more values set than a simple atomic task Right click on the task and choose Set Instance Detail Ensure that you are viewing the Bounds tab of the dialog as per Figure 1 12 Choose the Instance Creation mode In either mode the number of task instances created at runtime 1 3 CREAT
83. ne Australia 2006 Avail able through http www yawl system con 85
84. ne or more elements called order of BookOrder type unbounded means there is no upper limit on the number of order records we can include in the book list Once this is added we can start populating the data perspective of the specification e Create a net level variable called MasterList of type BookList and usage Local Tip In the Update Variable dialog Type dropdown user defined types are listed after all the built in simple types Give the variable this initial value lt order gt lt title gt YAWL User Manual lt title gt lt price gt 0 00 lt price gt lt inStock gt false lt inStock gt lt order gt When entered correctly the text will become green to show that it is a valid value to assign to the Masterlist variable of complex type BookList since it defines values for the elements of one BookO rder It is important that an initial value is provided for this variable because our definition of the BookList type specifies that it will contain at least one element that is because it doesn t include a minOccurs 0 clause If there was no initial value specified for this type the specification would fail schema validation at runtime in other words the Engine will reject the specification CHAPTER 1 THE EDITOR e Add a decomposition to the first atomic task and call it Create Book List Add to the decomposition a variable called bookList of type BookList and usage Input
85. net for our scenario 5 You are now ready to start drawing your specification 1 3 2 Atomic Tasks Click on the Add an Atomic Task button al in the Workflow Elements Panel or right click in an empty area of the canvas and choose Atomic Task Position your mouse just to the right of the Input Condition the symbol and click the left mouse button once to place an Atomic Task Set the decomposition of this task by right clicking on the Atomic Task and choosing Select Task Decomposition You should see a dialog as per Figure 1 4 Press the Create button and in the following Update Task Decomposition dialog enter the de composition s label 14 CHAPTER 1 THE EDITOR Rene Atomic Task Set decomposition to gt Create Done Cancel Figure 1 4 The Select Task Decomposition dialog See Section 1 5 5 for a full explanation of this dialog s features Set the label to Begin My Career and click the Done button 5 Note that by default a task takes on the label of the decomposition that it is associated with several tasks are allowed to share the same decomposition Once you ve created your task you are free to relabel the task to whatever you like This can be done by right clicking on the task and choosing Set Label from the pop up menu This will not change the name of the decomposition with which the task is associated 6 Connect the Input Condition to your Ato
86. ntime by the System The distribution set may consist of any number of participants and or roles These can be picked from the relevant lists in this dialog multiple selections are supported Additionally in the Net Parameters panel you may nominate one or more net level variables that at runtime will contain a value of the userid of a participant or the name of a role that is deferred allocation For a variable to appear in the Net Parameters panel it must be of type string and usage Input amp Output or Input Only Note that all net level variables that are of string type and have one of those usage types will be listed in the Net Parameters table and will initially all be set as referring to Data For each of those that will contain resourcing information at runtime the Refers To value must be changed to either Participant or Role via the drop down list on each row depending on the type of resource the value will refer to at runtime Step 3 In Step 3 shown in Figure 1 56 we can filter the set of participants that have been described in Step 2 Filtering can be done over capabilities and or over positions and organisational groups Moreover from this dialog it is possible to e allow the work items of the selected task to be offered only to participants who are members of the set specified in Step 2 and have previously completed work items of another task as specified in the current process
87. o store specific information relating to that task in a similar way to adding variables to a net Task variables have several uses One use is for transferring information between workflow users and the workflow engine A second use is for passing data between web services and or external code and or applications that the running workflow engine invokes and the Net the task resides in For example if your task is called Purchase a Book you may want to store the name and or ISBN of the book being ordered 1 5 6 Adding a Variable to a Task 1 First select the task that will require the variable ra We will be setting up variables for the Enrol task Go to the Attend University Net and select the Enrol task 34 CHAPTER 1 THE EDITOR 2 Right click on the task and choose Task Decomposition Detail An Update Task Decomposition dialog box will appear ra Retrieve the decomposition detail for the Enrol task 3 Click on the Create button An Update Task Variable dialog box will appear SOO Update TaskVariable 0 Extended Attributes Log Predicates Name Batre Type string HH Usage input amp Output HA Default Value Done Cancel Figure 1 28 Updating the Task Variable 4 Enter the Name of your variable choose the Type of the variable and its Usage from those listed click Done then Done again to exit the task decomposition detail dialog ra Enter StudentNumber for
88. o the net and Reset net reduction rules can be applied to the Reset net that results from the mapping of a YAWL net The application of these reduction strategies may significantly reduce the workflow that needs to be analysed hence it may significantly reduce the time that verification takes Note that there is overhead associated with performing the reductions themselves Also worth mentioning is that the soundness check is supported for workflows with a finite state space The editor caps the state space at a certain number of states and tries to construct the reachability graph for the workflow If the upper bound is not exceeded the soundness of the workflow can be determined with certainty 3WofYAWL is currently only available for Windows environments 1 9 AUTOMATED TASK ov The wofYAWL analysis tab page of the Configure Specification analysis dialog is shown in Figure 1 51 The reader is referred to 5 for a detailed explanation of the concepts behind this approach to verification Configure Specification Analysis Reset Net Analysis WofrAWL Analysis Use the WofrAWL analysis algorithm Structural check for relaxed soundness in a bounded analysis net Behaviourial check for semi positive transition invariants in a short circuited analysis net These tests may overlap in identifying unreachable tasks in the specification potential deadlocks and possible unfinished work in completed workflow cases Extend coverability
89. o the task in the same manner as dynamic forms Custom forms may be built using any web based technology such as JSF Javascript NET PHP or any other browser based environment that can receive data use it to populate form fields update the data with user inputs and pass control back to the calling service To set a custom form for a task right click and select Set Custom Form then enter the absolute URI of the custom form see Figure 1 61 To remove a custom form association open the dialog and enter a blank URI i e remove the URI from the dialog and click OK See the YAWL technical manual for information regarding the creation and configuration of custom forms 66 CHAPTER 1 THE EDITOR BOO Set Custom Form URI Please enter a URI for the Custom Form http www myserver com form js pl Figure 1 61 Custom form dialog 1 13 Configurable YAWL A configurable process model is an integrated representation of multiple variants of a same business process in a given domain such as multiple variants of an insurance business process operating in different markets A configurable process model offers the following benefits over traditional process models e eliminates redundancies in a process family e fosters standardization and reuse of proven practices e enables a clear distinction between commonalities those parts that are shared by all process variants and variants th
90. om this dialog it is possible to set an activation type and an expiration value for the timer The timer can be activated either when a task is enabled i e is offered or allocated or when it starts These have different meanings according to the type of task manual vs automated 1 11 1 Activation on enablement e In the case of a manual task as soon as the task is enabled the timer begins and it remains live so long as the specified expiry time is not reached During this time frame the task will follow the normal 64 CHAPTER 1 THE EDITOR resource assignment policy In other words it will be offered and can be allocated and started Once the timer expires the task instance will complete no matter what its current status is offered allocated started The possible danger of this behaviour is that a work item might be timed out while being edited by a user in which case any modifications the user makes after that time are lost e In the case of an automated task the timer works as a delay i e the automatic execution of the task instance created by an automated task is delayed until the specified expiry time is reached Once the timer expires the task is immediately executed and completed 1 11 2 Activation on starting e In case of a manual task the timer begins only when the task has started Therefore the task will be first offered then allocated and once it is started the timer starts Again the timer may expire
91. ons to the right of the list allow you to reorder the evaluation sequence of the predicates so that the default predicate the one you want to activate when all others fail can be placed at the bottom of the list Carefully ordering the evaluation sequence is especially important when dealing with an XOR split because only the first that evaluates to true will be activated and all subsequent flows will be ignored 1 5 ADDITIONAL SPECIFICATION FEATURES 606 Update Parameters for Atomic Task Enrol Input Parameters Expression Task Variable New_Net_1 SubjectCode text SubjectCode Fexternal SimpleExternalDBGatewayImpl StudentNumber Task Variables Mame Type Usage StudentNumber string Input amp Output SubjectCode i string Input amp Output Net Variables Mame Type Usage SubjectCode string Local Output Parameters Expression Net Variable Create Enrol SubjectCode text Subjectcode Update Remove _ Figure 1 34 Established task parameters with external mappings 600 Choose Starting Net Execution of the workflow starts in net Attend University a External data gateway for case data Done Cancel Figure 1 35 Setting an external data gateway from case start and completion Al The currently selected flow in the dialog will be identified by being highlighted green in the Net Figure 1 36 To specify a predicate f
92. or Users adamsmj Documents research temp myCareer yawl 0 ajalalalelo ke Ga lela maje ml a sale 00 O r We My Career Ol Study_Privately O Attend_University Og 2 Task Icon Attend Begin My Get a Job Career Geo Career University Started gt 18 Manual tt Automated gt B Routing ea Bad Task Study Privately F h Atomic Task Bad Task 228 is not on ESAERA directed path between the input and output conditions Left click on the selected net to create a new atomic task Figure 1 47 A invalid specification 1 Click on the Save button Bl on the Menu Toolbar or click Specification on the Menu and choose Save Specification The Specification File Save Options dialog appears Figure 1 48 O Specification File Save Options Specification ID InsuranceClaim Version Number 0 1 M Verify on save Analyse on save M Auto Increment Minor Version Number A Create backup Po oK Cancel Figure 1 48 Specification File Save Options dialog If this is the first time the specification has been saved and a Specification ID has not yet been entered via the Update Specification Settings dialog a Specification ID field will appear in the dialog all Specifications must be given a valid ID The ID can be a combination of alphanumeric characters and the underscore but cannot start with a numeric character Once se
93. or a particular flow select the flow from the list and click on Predicate Enter a predicate as a boolean XQuery expression and choose Done Note that a net level local integer variable called score has been introduced to the net for the purposes of showing how to create a boolean XQuery expression for a flow predicate it is not used again in this tutorial Timer Predicates Timer predicates are special non XQuery expressions that may be used as flow predicates For each task that has a timer associated with it cf Section 1 11 an implicit net level timer state variable is created and maintained at runtime At any particular time during the execution of the net a timer state variable can have one of four values Table 1 1 42 CHAPTER 1 THE EDITOR My Career Ol Study Privately JAttend_University H Begin My Get a Job Career Career University Started ii 000 Flow detail for Atomic Task Begin My Career Target Task Predicate Attend University number My Career score text gt 65 Study wendy Pravataiy SEDAR b Predicate Privately ud The bottom most flow will be set to true and used as the default nl Done ee oe el Figure 1 36 Updating Flow Detail dormant Timer has not yet started active Timer is running closed Task completed before timer expired expired Timer expired before task completed Table 1 1 Valid states of timer state variables A timer p
94. ose parts that are specific to certain process variants in a process family e can be configured to meet specific requirements such as those of a new organization product or brand The YAWL Editor supports the definition of configurable YAWL C YAWL models A C YAWL model is a YAWL model where some tasks are annotated as configurable These configurable tasks represent the variable parts of the process model and are distinguished by a thicker border from the remaining tasks representing commonalities Let s have a look at the example C YAWL model in Figure 1 62 This model de picts a travel requisition process you can find it in the YAWL distribution under the folder C YAWL models In this example all tasks but the task labeled tau are configurable Configuration is achieved by restricting the behavior of a C YAWL model Configurable tasks can be restricted via the notion of ports A configurable task s joining behavior is identified by one or more input ports whereas its splitting behavior is identified by one or more output ports The number of ports for a configurable task depends on the task s routing behavior e AND split AND join and OR join are each identified by a single port e XOR split and XOR join are identified by one port for each outgoing incoming flow e an OR split is identified by a port for each combination of its outgoing flows For example task Submit Travel Form for Approval has two input ports
95. osen to fill the order A multiple instance task called Get Quotes is used to gather the product quotes from suppliers The Update Parameters dialog for the Get Quotes task can be seen in Figure 1 41 48 CHAPTER 1 THE EDITOR 606 Multiple Atomic Task Get quotes Instance Detail Multiple Instance Variable Supplier HH Accessor Query Purchase order Suppliers Splitter Query for s in Suppliers return s Instance Query Get_quotes Supplier Aggregate Query for s in Get_quotes Supplier return s Result Net Variable Suppliers H Done Cancel Figure 1 42 Instance Detail dialog for the Get Quotes MI task The task has two variables defined PONumber the purchase order number and Supplier the details of a single supplier Notice that PONumber is defined as Input Only and is mapped from the net level variable of the same name this means that the purchase order number will be displayed within each of the workitems created from the MI task Notice also that while a list of Suppliers is mapped in from a net level variable the mapping expression maps to a single supplier one for each task to be created Also the Output Parameter mapping takes a single Supplier from the task and maps it to the net level list of Suppliers The MI queries for the task can be seen in Figure 1 42 Again note that the Accessor Query exactly matches the Input
96. ow do I find out more about the elements and principles of the YAWL workflow specifications For more information about the mechanics of the YAWL workflow elements please consult the YAWL website http yawlfoundation org 84 CHAPTER 1 THE EDITOR Bibliography 1 2 3 4 6 W M P van der Aalst and K M van Hee Workflow Management Models Methods and Systems MIT Press Cambridge MA USA 2002 F Gottschalk W M P van der Aalst M H Jansen Vullers and M La Rosa Configurable Workflow Models International Journal of Cooperative Information Systems 17 2 177 221 2008 A H M ter Hofstede W M P van der Aalst M Adams and N Russell editors Modern Business Process Automation YAWL and its Support Environment Springer 2010 N Lohmann and D Weinberg Wendy A tool to synthesize partners for services In J Lilius and W Penczek editors 31st Int Conference on Applications and Theory of Petri Nets and Other Models of Concurrency volume 6128 of Lecture Notes in Computer Science pages 297 307 Springer 2010 H M W Verbeek Wil M P van der Aalst and Arthur H M ter Hofstede Verifying Workflows with Cancellation Regions and OR joins An Approach Based on Relaxed Soundness and Invariants Computer Journal 50 3 294 314 2007 Moe Thandar Wynn Semantics Verification and Implementation of Workflows with Cancellation Re gions and OR joins PhD Thesis Queensland University of Technology Brisba
97. pecification shown in Figure 1 37 which begins by compiling an order a list of book titles 1 5 ADDITIONAL SPECIFICATION FEATURES 43 Create Book Verify List Show List List Figure 1 37 Example specification with a Multiple Instance Task It then creates a number of MI task instances one for each book title in the list of books Once all the MI task instances complete the updated list is recomposed and shown in the final task To prepare this specification drag two atomic tasks and one MI task onto the canvas We then need to define a complex data type to store the entire book order Open the Update Data Type Definitions dialog from the Specification menu and enter the following two complex type definitions lt xs schema xmlns xs http www w3 org 2001 XMLSchema gt lt xs complexType name BookUOrder gt lt xs sequence gt lt xs element name title type xs string gt lt xs element name price type xs double gt lt xs element name inStock type xs boolean gt lt xs sequence gt lt xs complexType gt lt xs complexType name BookList gt lt xs sequence gt lt xs element maxOccurs unbounded name order type BookUOrder gt lt xs sequence gt lt xs complexType gt lt xs schema gt The first defines a complex type called BookOrder which is a record with three simple type fields The second defines a complex data type called Booklist which consists of an array of o
98. redicate can have one of two operators equals or not equals and takes the form timer name_of_task operator timer state For example assuming a task called Enrol has a timer then on any outgoing flow from an OR split or XOR split in the net that contains the Enrol task the following example timer predicates are valid e timer Enrol dormant e timer Enrol expired e timer Enrol expired Note Timer predicates are case sensitive including the timer keyword the name of the task and the state value 1 5 9 Multiple Instance Queries Now that we have an understanding of parameter setting and XQueries we can revisit from a data perspec tive parameter setting for the particular requirements of Multiple Instance MI Tasks In general terms an MI task receives as input from a net level variable mapping a variable of complex type typically a list of some other data type but more complex constructions are of course supported too which it then splits into a number of logically distinct data values to form the data that is assigned to each task instance When the MI task completes it gathers all the individual pieces of data from the various task instances and reconstructs the complex type variable so that it can be mapped back to the net level variable To illustrate the operation of MI tasks with particular emphasis on the data perspective we will use the List Builder s
99. riables and a label to associate with the task Unlike nets which cannot share net decompositions there is a 1 N relationship between task decompositions scoped to the entire specification and their tasks scoped to nets meaning that a number of tasks within a specification may share the same decomposition Besides variables and a label task decompositions also allow the workflow designer to identify which web service the decomposition should invoke in a running workflow engine and whether the decomposition will create manual i e human actioned or automated non human actioned tasks When two tasks share the same decomposition we are saying that the same activity is required in two different places in the workflow the two tasks may be named the same or differently but they will share the same underlying definition of work From the Select Task Decomposition dialog you can use the drop down list to select an existing decomposi tion or alternately you can click the Create button to generate a new one that will become the task s decomposition Figure 1 27 600 Atomic Task Get a Job Set decomposition to Get_a_Job Feel_Smarter Iv Get_a_Job Pass_All_Subjects Begin_My_Career Create ead a Book p Look_for_an_Easier_Book Get_Degree Career_Started 7 Figure 1 27 Select Task Decomposition example Get a Job task 1 5 5 Task Decomposition Detail Task Variables You can add variables to a task t
100. riables from the parent net to the sub net then their usage type in the sub net will need to be changed from local to Input Only since they are not to be updated in the sub net s tasks the perform the appropriate mapping between the parent net and the Attend University composite task following the method described above Defining Parameters using External Data Sources As an alternative to mapping parameter values from net level to task level and back again task and case parameters may be assigned values directly from an external data source on starting and be directly mapped back on completion External data sources are accessed via a specific Data Gateway To see a list of available data gateways choose the Data Gateway tab in the Update Task Parameter dialog Figure 1 33 Figure 1 33 shows a single data gateway in the list SimpleExternalDBGateway an example gateway that ships with YAWL any other gateways defined for particular specifications will also be listed here see Note below The combo box at the bottom of the dialog shows which parameter will receive the data from the gateway selected When the Done button is clicked the selected gateway will be displayed as a special external mapping expression in the Update Parameters dialog Figure 1 34 A case level external data gateway may also be chosen so that each time a case is started for a specification the chosen data gateway will be called to pop
101. rom a pre 2 0 version of the editor i e a ywl file 1 Click on the Import a YWL Specification file button 63 on the Menu Toolbar or click Specification on the Menu and choose Import from YWL File A window will appear asking you specify the YWL file to import 2 Select the file and choose Open The YWL file will be loaded and converted to a YAWL 2 0 version specification The specification can now be edited and saved as a 2 0 specification in the usual way 1 8 Specification Analysis Verification of specifications for the engine only determines whether the engine will be able to successfully load and begin execution of the specification In contrast the analysis tool can be used to test for deeper issues in the specification The analysis toolbar button a or the matching Analyse Specification menu item under the Specification menu allows workflow designers to analyse their specifications A number of potential problems with a work flow can be automatically spotted with analysis Examples include spotting potential deadlock situations unnecessary cancellation set members and unnecessary or join decorators at run time or joins require sig nificant processing effort and should be removed or replaced with other join types if they are not actually needed A configuration dialog for specification analysis is available via the Tools menu Configure Specification Analysis see Figure 1 49 Note that many of the option
102. ry of entire element will return the entire XML element of the selected variable which is useful for times when you want to create a complex type expression from individual variable elements Experience with XMSchema and XQuery are necessary to understand the effects this button will have on runtime YAWL engine state From the list of task variables select the SubjectCode task variable and click add XQuery of element s content From the list of net variables select the SubjectCode variable Click Done Create another Task Parameter and map the task StudentNumber to the net variable of the same name using this technique Click Done and Done again These Parameters were set up to demonstrate a simple transfer of state from a net to a task and back to the net Perhaps the task would allow a user to change the values of one of the variables which would eventuate in the net s values changing The Update Parameters dialog box should appear as in Figure 1 32 Now that we have an understanding of net level and task level tasks and how to create parameters to map values between them we can revisit the earlier example from Section 1 5 7 where we created two local variables for the sub net Attend University By creating them with local usage type they have local scope and so are actually different variables than those of the same name created in the outer parent net My Career If you wanted to map the values of those va
103. s The Workflow Elements and Tools panel contains seven selectable buttons five YAWL language icons and two selection tools that assist with creation selection and positioning of objects within your specification This panel is also accessible by right clicking on any blank area of the canvas Once an element is selected it is possible to place objects of that type on the canvas by left clicking the mouse button at the desired location 1Only available when installed in a Windows environment 1 2 THE YAWL EDITOR WORKSPACE 11 Atomic Task im Select this button to create an Atomic Task which represents a single task to be performed usually by a human participant or an external application or service Composite Task Bl Select this button to create a Composite Task which is a container for another YAWL sub Net with its own set of YAWL elements constrained by the same syntax Multiple Instance Atomic Task ia Select this button to create a Multiple Instance Atomic Task which allows you to run multiple instances of a task concurrently Multiple Instance Composite Tasks a Select this button to create a Multiple Instance Composite Task which allows you to run multiple instances of a composite task concurrently Condition Ol Select this button to create a Condition which is a way to represent state for the Net Marquee Selection a 1 1 L Select this button to activate the Marquee Sele
104. s are disabled by default since they are resource intensive and may take some time to complete for large and or complex workflows It is recommended that analysis of such specifications not be done incrementally but rather at planned checkpoints during specification development Because analysis make take a long time and is very resource intensive it may appear that the Editor has frozen during an analysis although it is very unlikely that this will actually be the case To provide some feedback about the progress of the analysis a dialog will appear which shows updates and messages see 1 8 SPECIFICATION ANALYSIS 59 Figure 1 50 The dialog includes a checkbox that when checked will keep the dialog open after the analysis completes so that the messages may be noted This functionality can also be controlled via a setting in the Configure Specification Analysis dialog see Figure 1 49 000 Configure Specification Analysis WofYAWL Analysis M Use the reset net analysis algorithm Use YAWL reduction rules before analysis for optimisation Use Reset reduction rules before analysis for optimisation __ Check for weak soundness property using coverability Check for unnecessary cancellation regions Check for unnecessary or joins Wi Check for or joins in a cycle M Check for soundness property using reachability results from bounded nets Show observations in analysis results These tests may overlap
105. s can easily add new codelets to perform various operations which will immediately be available to process designers via the dialog above as long as there is a valid connection to the Resource Service 1 10 Resource Management Manual task Once a connection with the Resource Service has been established any manual atomic task with a decom position a task is manual by default and only becomes automated when explicitly checked as automated in the Task Decomposition Dialog can be allocated resources via a number of steps by right clicking on the task and selecting Manage Resourcing This will launch the resource manager wizard Figure 1 54 shows the dialog window for Step 1 of the wizard Step 1 In Step 1 we can specify the interaction strategy for work items of the selected task There are three interaction points offer allocation and start each of which may be either User or System processed If we choose that work items are to be Offered by the User and not by the System at runtime an Administrator will need to manually choose the resource s to offer the work item to If System offering is chosen then in Steps 2 and 3 we can specify the resources that will automatically be offered work items of the task at runtime If we choose that work items are to be Allocated by the User and not by the System any participant who has been offered the work item can manually choose whether to commit to being responsible for the performance of t
106. sible for performing the work of the task instance For example a decomposition may be set up to place an order with an external company Upon execution of any task using this decomposition data could be transmitted via a Web Service invocation to this company To have a decomposition invoke custom YAWL service do the following 1 Right click on a task the choose Task Decomposition Detail An Update Task Decomposition dialog box will appear see Figure 1 29 2 In the YAWL Registered Service Detail panel Select the required Web Service from the dropdown list of those available in the Engine 3 Click Done to finish 92 CHAPTER 1 THE EDITOR If the Editor is connected to a valid running YAWL Engine instance the YAWL Service Dropdown Box will contain entries for all custom YAWL services the engine has registered Otherwise only the Default Worklist of the Resource Service will be available When you select a YAWL Service the Editor will query this running engine for the mandatory input and output variables required by the service if any and will populate the decomposition variables of the selected task with those variables Core custom services that are supplied with the engine include one for RPC Style Web Service Invocation WSInvoker Service and one for supporting flexibility and exception handling for YAWL processes Worklet Service Optional services include an SMS handler a digital signature service and a em
107. t this field will not reappear in 54 CHAPTER 1 THE EDITOR subsequent saves of the specification The Version Number field provides a version number for the specification Version numbering al lows different versions of the same specification to co exist in the Engine YAWL specification version numbers consist of a major part to the left of the point representing a major revision and a minor part to the right of the point representing a minor revision Version numbers begin at 0 1 you may edit the version number directly to a higher version number at any time If the Auto Increment Minor Version Number checkbox is checked the minor revision will increase by one each time the specification is saved The Verify on save and Analyse on save checkboxes if checked will verify and and or analyse the specification before it is saved providing a final check of the specification note verification and analysis may take some time for large and or complex models and analysis in particular should be unchecked for incremental saves of such models The Create backup checkbox if checked will copy the previous version of the specification file to a file of the same name but with a bak extension Checking this option is recommended Once the dialog is completed click OK to save the file This saved specification file can now be loaded into a running YAWL Engine and executed To import a specification file f
108. t from the context menu The task will be fill with a grey colour to indicate that this is the task that owns the cancellation set currently on view Create the Purchase Book specification as shown in Figure 1 19 In this example we are going to purchase a book by placing an order with three different sellers as soon as the first seller fills the order we want to cancel the other two orders To achieve this we create a cancellation set for each Order task that includes the other two Order tasks We will step through creating a cancellation set for the Order from Amazon task the other two are created in a similar manner Right click on Order from Amazon and choose View Cancellation Set 1 5 ADDITIONAL SPECIFICATION FEATURES 27 er from Amazon Order from Booktopia Get Book Details Order from Bookfinder Figure 1 19 The Purchase Book specification 3 Next choose a task condition or flow and thus an implicit condition to add to the Cancellation Set Hold down the shift key to select more than one object for cancellation Select the Order from Booktopia and Order from Bookfinder tasks and the flow relation preceding each of them 4 Click on the Add Selected Items to Visible Cancellation Set button l on the Menu Toolbar Items will be given a red border to indicate they belong to the cancellation set of the
109. te study that will eventually lead them to getting a job and starting their new career 1 3 CREATING YOUR FIRST SPECIFICATION 1 3 1 Creating Your First Specification 13 1 Click on the Create a New Specification button B at the top left of the Menu Toolbar or click on Specification in the Menu and choose Create Specification This will create a blank Net called New Net 1 which will be by default the starting net of the workflow For details on selecting a starting net consult Section 1 3 6 Click on Specification in the main Menu and choose Update Specification Properties A screen as per Figure 1 3 will appear Alter the specification s properties as you feel appropriate 800 Update Specification Properties Specification ID ManualExample Specification Name Manual Example Specification Description I Specification Author bloggs Version Number 0 3 Iway Specification valid from setae the date of 23 07 2008 Specification valid until ey the date of 23 07 2008 Done Cancel Figure 1 3 Specification Properties Dialog 3 Rename this Net by clicking on the Net Menu and choosing Update Net Detail 4 Enter the new name of the Net in the Decomposition Label field then click the Done button Decomposition Variables will be explained later in Section 1 5 8 Change the name of the Net in the Decomposition Label to My Career This Net will be the primary
110. the criteria selected below will be offered the task Filter Parameter Value O Filter by Organisational Data O Filter by Capability Runtime Constraints Allow this task to be piled to a single participant Choose participant s who completed previous task Receive purchase requisition Y Do not choose participants who completed previous task Receive purchase requisition HH Finish Figure 1 56 Step 3 of the resource management wizard e do not allow the work items of the selected task to be offered to participants who are members of the set specified in Step 2 and have previously completed work items of another task as specified in the current process instance e Allow all of the work items of the selected task to be piled to a particular participant which means that if a participant chooses to pile a work item of the task that participant will be automatically allocated the work item and all future instances of work items of the task for all future instances of the process containing the task until such time as piling is turned off for that task by the participant or an administrator 62 CHAPTER 1 THE EDITOR Step 4 In Step 4 shown in Figure 1 57 we can select the allocation mechanism that determines at runtime which participant chosen from the members of the distribution set defined earlier will actually be allocated the work item The currently available mechanisms are
111. the outermost braces are optional d is used simply to differentiate it from e in the splitter query but its name is unimportant Result Net Variable this specifies the net level variable to which the results of the aggregate query is to be mapped 606 Update Parameters for Multiple Atomic Task Get quotes Input Parameters Expression Task Variable Purchase order PONumber text PONumber Purchase order Suppliers Supplier Pe Update Create Remove Task Variables Name Type Usage PONumber string Input Only Supplier Supplier Input amp Output Output Parameters Expression Net Variable Create Get_quotes Supplier Suppliers Update hs Remove Figure 1 41 Update Parameters dialog Get Quotes task When this specification is executed it will first allow the user to specify a number of book orders then will split the details of each into a corresponding number of MI task instances one for each order The price and availability of each order can be updated within its own task instance When all or the threshold of MI task instances have completed their data will be aggregated back into the list for display in the third and final task For a second example consider a process that raises a purchase order to purchase a particular product The business rules for this process require that at least three quotes are needed for any purchase from which one is ch
112. ting Task Variables section Go to the Attend University Net and select the Enrol task 2 Right click on the task and choose Update Parameters An Update Parameters dialog box will appear Figure 1 31 Update the Parameters for the Enrol task 3 In the Output Parameters section click on Create An Update Net Parameter dialog box will appear similar to Figure 1 31 4 If you have already set up a Task Variable for this task then the Existing Task Variable option will be activated and there will be a list of task variables to choose from Choose a variable from the list and click on Done then Done again to close the task parameters dialog If you haven t set up Net Variables then click on Create and return to the previous section Section 1 5 3 38 CHAPTER 1 THE EDITOR If you are familiar with XQuery syntax then you can paste in an XQuery to allow manipulation of the Output Parameters Syntactically well formed XQueries will be green and badly formed ones will be red For workflow designer convenience two XQuery buttons are supplied to generate XQuery expressions from available task variables The add XQuery of element s content button will return just the content of the XML element for this variable which is useful for simple state transfer between two variables of the same XML Schema type and expected to be the typical button that users will start out with The other button add XQue
113. to set default configuration values for each port by pressing the button Set Defaults Once default configuration values have been assigned to a port the button Use Default will become available when selecting that port and you can configure that port by using its default value All configuration settings including default values are stored in the YAWL specification upon saving so this information will be preserved after closing the model Let s block the output port of task Submit Travel Form for Approval towards task Request for change and let s make task Check and Update Travel Form silent by hiding its input port With the first operation we deny requests for changes after a travel form has been submitted by blocking the flow into the loop path while with the second operation we deny the possibility of checking and updating a travel form although in this case we don t block the flow through the hidden task 68 CHAPTER 1 THE EDITOR r Output Ports Configuration PortID Target Nodes Configuration 0 Request for change activated 1 Reject Travel Form activated 2 Approve Travel Form Admin activated Activate Block Use Default Set Defaults Figure 1 63 Configuring the input ports of a task The YAWL Editor can show a preview of the resulting configured net by graying out all model fragments which have been removed You can do this by pressing the Preview
114. ttribute only applies to fields that would otherwise not be read only That is a variable with usage type Input Only will display as read only regardless of the value of the readOnly attribute so the attribute will only apply to variables of usage types Input amp Output or Output Only e For attributes that require a URL value absolute URLs must be used A simple solution is to create a subdirectory in the tomcat webapps directory called for example images and place the images within it Then the absolute URL would be for example http localhost 8080 images myImage png assuming tomcat is installed locally e To avoid confusion care should be taken when overriding the background color of a field that the color used for validation errors 4FFCCCC or colours close to it are not used e A mechanism exists for extended attribute values to be set and or modified at runtime please see the Technical Manual for more information 1 15 2 User Defined Extended Attributes User defined extended attributes are specified in property files one for decomposition level attributes and one for variable level attributes By default the Editor will look for attribute property files in the folder lt editor_install_path gt YAWLEditorPlugins ExtendedAttributeProperties 1 15 EXTENDED ATTRIBUTES V alert background color blackout font color font family font size font style fractionDigits hide hidelf image
115. ulate its case level variables and when each case completes the data gateway will be called to update output values from the case back to the specified external data source To choose an external data gateway at the case level select Net Set Starting Net from the main menu then choose the desired external data gateway from those listed in the dropdown on the dialog that displays Figure 1 35 Note Specific data gateways must be created for each specification that wishes to access an external data 1 5 ADDITIONAL SPECIFICATION FEATURES 39 BOS Update Parameters for Atomic Task Enrol Input Parameters XQuery Task Variable Create Attend University StudentMumber text StudentNumber Attend University SubjectCode text SubjectCode Pe Update Remove Task Variables Name Type Usage string Input amp Output SubjectCode string Input 4 Output Net Variables Name Type StudentNumber string SubjectCode atring Output Parameters XQuery Net Variable Create Enrol StudentNumber text StudentNumber _ j Enrol SubjectCode texti SubjectCode Update Done Figure 1 32 Established task parameters with XQuery mappings source directly How to create a data gateway is outside the scope of this manual Please refer to the YAWL Technical Manual for details Notes about parameters e For simple assignments such as those in Figure 1 32 the XQuery expressions for the input p
116. ut Sub jectcode string Input amp Output Net Variables Name Type StudentNumber string SsubjectCode string Output Parameters Net Variable Create Update hd Remove Done Figure 1 30 Updating Parameters for a Task variables and the variables of its containing net In the Input Parameters section click on Create An Update Task Parameter dialog box will appear If you have already set up a Task Variable for this task then the Existing Task Variable option will be activated and there will be a list of task variables to choose from Choose a variable from the list and click on Done then Done again to close the task parameters dialog If you haven t set up Task Variables then click on Create and return to the previous section dealing with Task Variables Section 1 5 7 If you are familiar with XQuery syntax then you can add an XQuery expression to allow manipulation of the Input Parameters Syntactically well formed XQueries will be green and badly formed ones will be red Again red text will be accompanied by a split pane table returning the parse errors that cause the text to be badly formed For workflow designer convenience two XQuery buttons are supplied to automatically generate XQuery expressions from available net variables The add XQuery of element s content button will return just the content of the XML element for this variable which is useful for simple value transfer between two v
117. ut ports can be hidden or blocked Hiding an input port corresponds to making the task silent i e the task will still be executed but its decomposition will be removed and thus the task won t have any observable behavior Blocking an input port corresponds to inhibiting control to the task via that port i e it will no longer be possible to execute the task via that port e Output ports can only be blocked This means that the outgoing paths from that task via that port will be disabled Moreover you can block the cancelation region assigned to a task this means that the task s region will be removed altogether and restrict the parameters of a multiple instance task Specifically you can reduce the maximum number of allowed instances increase the minimal number of allowed instances and the continuation threshold and change the dynamic creation of instances to static The configuration of input ports output ports cancelation regions and multiple instance parameters can be accessed by right clicking on a configurable task and then selecting Process Configuration gt Input Ports Output Ports etc Figure 1 63 shows the dialog window for the output ports configuration of task Submit Travel Form for Approval You can select a single port or multiple ports by using the Shift or Ctrl keys and then press the Hide or Block button to configure the selected ports or Activate to rollback a configuration It is also possible
118. valid XQuery expression e text a long text value When the text field of an attribute with color font xquery or text type is selected a small Open Dialog appears on the right hand side of the field When clicked a dialog appropriate to the type will be displayed Enter or select an appropriate value from the dialog then click OK to save the value to the attribute Figure 1 73 shows the dialog that appears for attributes of type font OOO Update Task Decomposition Enrol Standard Extended Attributes Log Predicates Name Value background alt color font color font name Baskerville EA font size 12 font style None HH header font color header font name Courier New header font size 600 Font Picker header font style Bl Family Style hideHeader Baskerville Regular ieee Cia Bell Gothic Std Bold justify le BiauKai 0 Italic label Bickham Script Pro Bold Italic page background color Big Caslon Size age background image Birch Std k ij i Sisekmnoor LET readOnly Blackoak Std 7 title Preview Blackmoor LET 36 R 4 l Done OK 3 Cancel 2 z i a Figure 1 73 Extended attributes font type dialog The following is an example of a property file that defines the attributes description help mode refresh and showDetails comments are indicated by a line starting with Decomposition Attributes Wed May 14 17 35 42 AET 2008 descript
119. ve type compatible task variables of the same name created for them and mappings that will enact a direct data copy between the newly created task variables and the specified selected net variables Decomposition name Enrol in Subject Net Variables for Input Net Variables for Output Name Type Wi StudentNumber string SubjectCode string Done Cancel FF i Figure 1 43 An example of the direct data transfer dialog All of the available net level variables for the task s containing net will be listed in the dialog Simply check the boxes for the desired inputs and outputs This dialog will automatically create a task decomposition and matching XQueries to directly transfer data from a selected net variable to a task variable of the same name and back again 1 5 11 End of Scenario This is where our scenario ends The My Career Scenario was designed to outline the basic the functions of the YAWL Editor and to provide you with a understanding of designing a YAWL workflow specification But the functionality of the YAWL Editor does not stop here If you are after something more challenging try adjusting your version of the scenario to expand into more sub Nets and more complex situations 1 6 Connections 1 6 1 Connecting to the YAWL Engine Each atomic task in a YAWL specification must be associated with a service that will be responsible for performing the work of the task If you do not explicitly specify a ser
120. vice for a task by default the task will be 50 CHAPTER 1 THE EDITOR assigned to the Default Worklist Handler which by default is supplied by the Resource Service If you want to associate a task with a service other than the Default Worklist Handler you can make the appropriate choice from a list in the task s decomposition dialog see the following section The Editor populates the list of available services by making a call to a running Engine which returns the list of services currently registered with it Before this can occur the Editor must first establish a valid connection to a running Engine On Editor startup a connection to a running Engine is attempted If successful the Engine connection icon at the left of the status bar will turn green If unsuccessful perhaps because the Engine is not running or the connection parameters are incorrect the connection icon will show red After the Editor has started an Engine connection may be performed via the Settings menu To establish a connection with a running YAWL Engine 1 Click the Settings Menu and choose the Engine Connection item 2 From the resulting dialog Figure 1 44 accept the default values or enter the following engine details e YAWL Engine URI e Administrator s User Name e Administrator s Password 80 90 YAWL Engine Connection Settings YAWL Engine URI http localhost 8080 yawl ia User Name admin Test Connection Password ania
121. while the task is being edited by a user e This option is does not apply for an automated task 1 11 3 Expiry value The expiry value of the timer specifies for how long the timer will live after being activated Expiry values can be expressed in either of two ways e Using a specific date and time which means the timer will expire at the specified moment To set a specific date and time choose the at the time of radio button on the Set Timeout Detail dialog Figure 1 59 and enter the required values Care should be taken when setting a specific time value for timers if it happens that the specified value is earlier than the moment the task is actually enabled or started depending on when it is set to activate then the YAWL Engine will recognise that the timer has already expired and immediately complete the work item before it has a chance to appear on a worklist e Using a Duration value A Duration is one of the built in simple XML Schema data types and is used to represent a period of time When a Duration type is used as a timer expiry value the timer will expire exactly when that period of time has passed since the work item was enabled or started depending on when it is set to activate To set a specific duration choose the after a duration of radio button on the Set Timeout Detail dialog Figure 1 59 and enter the required value A Duration value is expressed in the following form PnYnMnDTnHnMn
122. will be used The specification consists of two atomic tasks the first requests an answer to the eternal question from a user while the second shows the answer provided in an Input Only variable Figure 1 75 shows the specification while Figure 1 76 shows how the dynamic form for the Answer task is displayed by default 0 98 Question Answer Figure 1 75 The EternalQuestion specification 606 YAWL 2 1 Edit Work Item m BB http localhost 8080 resourceService faces userWorkQueues jsp Qr Google Help us improve YAWL Edit Work Item 1136 2 Figure 1 76 The default dynamic form for the Answer task We would like to change the look of the form for the Answer task from the generic default to something more appropriate for this process so values are provided for external attributes as follows e At the decomposition level background color white FFFFFF page background image http localhost 8080 images guide2 jpeg hideBanner true title a space to suppress the title display label a space to suppress the task name label display e At the variable level the answer variable 82 CHAPTER 1 THE EDITOR font family Capitals font size 20 font color dark green 24009900 image above http localhost 8080 images guide jpeg image above align center hide true to suppress display of the text field text below The answer to the
123. xample of a task with all three available indicators is shown in Figure 1 7 The three task indicators left to right in Figure 1 7 are 1 3 CREATING YOUR FIRST SPECIFICATION 15 Begin My Go to Get a Job Career Career University Started Figure 1 6 The My Career Net Figure 1 7 Task Indicators e Timer This task has had a timer set see Section 1 11 e Automated This task has been set as automated see Section 1 9 If this automated task also has a codelet specified it will be filled green see Section 1 9 1 e Cancellation Set This task has had a cancellation set defined see Section 1 5 1 These task indicators are rendered on top of any icons set for the task Task Decoration Decorating a task is the process of adding a split and or join to the task By adding a split decorator to a task you are specifying that when the task completes it will be succeeded by one or more tasks Here are the possible choices for a task s split decorator e No split The task has no split decorator and so will have exactly one outgoing flow e AND split The task may have a number of outgoing flows when the task completes it will activate each and every outgoing flow e XOR split The task may have a number of outgoing flows each with an associated condition when the task completes it will activate exactly one outgoing flow the first that has its condition evaluate to true or the desig
124. y when should the timer expire This value can be either a date string for example 12 12 08 which will be interpreted as a specific moment or as a Duration value which will be interpreted as a period of time An example of how a variable of Y TimerType appears in a dynamic form at runtime can be seen in Figure 1 60 Edit Work Item 6 1 Figure 1 60 Example of a YTimerType variable rendered on a dynamic form 1 12 Custom Forms When a task is associated with the default worklist handler i e the Resource Service then at runtime the data within the task instance may be selected for viewing and or updating By default the Resource Service uses a built in dynamic forms component which generates appropriate but generic data editing forms designed for maximum flexibility and that can display data parameters of any type However their generic look and feel may not be appropriate in all cases for example where an organisation has a standardised set of forms for their business processes and would like their web based forms to match that standard In such cases a Custom Form may be user defined and associated with a task by specifying a URL to the form At runtime for such a task the Resource Service will package up the task data and send it to the custom form for display and or editing depending on how the form has been defined On submission of the form by the user the data is extracted from the form by the Service and passed back t

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