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The Worklet Custom Service for YAWL Installation and User Manual

1. Close Rules File Closes the currently opened rules file Only one rules file may be open at any one time Add New Rule Node Displays the Add Rule form to allow the addition of a new rule node to an existing tree to refine a worklet selection See the section below on the Adding a New Rule for more details Tree Viewer Displays the Tree Viewer form which provides the ability to view large trees in full screen mode Config Form Displays the configuration form discussed above About Box Displays some information about the rules editor version number date and so on Other Features Current Rule Type This drop down list displays each rule type that has a tree set defined in the opened rules file Selecting a rule type from the list displays in the Tree View an associated rules tree from the tree set Works in conjunction with the Task Name drop down list Current Task Name This drop down list displays the name of each task that has a rules tree associated with it for the rule type selected in the Rule Type list Selecting a task name will display the rules tree for that task in the Tree View This drop down list is disabled for case level rules types S Tree View This area displays the currently selected rules tree in a graphical tree structure Selecting a node in the tree will display the details of that node in the Selected Node and Cornerstone Case panels Nodes are colour coded for easier identification
2. o Blue nodes represent the root node of the tree o Green nodes are true or exception nodes i e they are on a true branch from their parent node o Red nodes are false or else nodes i e they are on a false branch from their parent node Selected Node Displays the details of the node currently selected in the Tree View Cornerstone Case displays the complete set of case data that in effect caused the creation of the currently selected rule see Adding a new rule below for more details In Figure 16 the Cornerstone Case data shows that amongst other things the variable Fever had a value of true while the variables Rash Wound and Fracture each have value of false Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 24 Adding a New Rule There are occasions when the worklet returned for a particular case while the correct choice based on the current rule set is an inappropriate choice for the case For example if a patient in a Casualty Treatment case presents with a rash and a heart rate of 190 while the current rule set correctly returns the TreatRash worklet it may be desirable to treat the racing heart rate before the rash is attended to In such a case as the Worklet Service begins execution of an instance of the TreatRash process it is obvious that a new rule needs to be added to the rule set so that cases that have such data both now and in the future will be handled correctly To add a new rule to
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4. Test Fever Workitem detail Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 41 Treat Fever Patient ID 123456 Notes bitten by spider Pharmacy jaspirin twiceaday Name Iva Payne t Treatment anti venene K Figure 35 Treat Fever Workitem detail When the Treat Fever workitem is submitted the worklet case is completed The Worklet Service maps the output data from the worklet case to the matching variables of the original Treat workitem then checks that workitem back in allowing the next workitem in the Casualty Treatment process Discharge to execute Go to the Available Work page and yov ll see that the Discharge workitem is available Figure 36 Edit it to see that the data collected by the TreatFever worklet has been mapped back to this workitem Submit it to complete the case Discharge Patient ID 123456 Notes bitten by spider Pharmacy aspirin twice a day Name Iva Payne Treatment janti venene Submit Figure 36 Discharge Workitem with Data Mapped from TreatF ever Worklet B Selection Worklet Enabled Multiple Instance Atomic Task Example This walkthrough takes the List Maker example from the YAWL Editor User Manual and worklet enables the Verify List task to show how multiple instance atomic tasks are handled by the Worklet Selection Service Worklet Custom Service Manual Beta 8 Worklet
5. and so the third Verify List workitem is checked back into the Engine by the Worklet Service the Engine determines that the Verify List workitem has completed and so the original process continues to its final workitem Show List Check out and edit the Show List workitem to show the changes made in each of the Get_Bob worklets have been mapped back to the original case Figure 41 Show List User List Insert after selected Delete selected om o o Bob two six x Bob one five Bob three seven x Figure 41 The Show List Workitem Showing the Changes to the Data Values Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 45 C Exception Constraints Example This walkthrough uses a specification called OrganiseConcert to demonstrate a few features of the Worklet Exception Service The OrganiseConcert specification is a very simple process modelling the planning and execution of a rock concert Figure 42 shows the specification as it appears in the YAWL Editor OrganiseConcert oc 8 BookStadium SellTickets DoShow Figure 42 The OrganiseConcert Specification First ensure the Exception Service is enabled see Section 2 for details Navigate to the YAWL Administrate page and upload the OrganiseConcert specification from the worklets folder of the worklet repository Then go to the Workflow Specifications page and launch an OrganiseConcert ca
6. called Treat that is worklet selection enabled We ll run a complete instance of the example specification to see how worklet selection operates Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 37 Navigate to the YAWL Administrate page and upload the Casualty Treatment specification from the worklets folder of the worklet repository Then go to the Workflow Specifications page and launch a Casualty Treatment case The case begins by requesting a patient id and name just enter some data into each field then click Submit Figure 29 Casualty Treatment Patient ID 123456 Name Iva Payne Figure 29 Launching a Casualty Treatment Case detail Go to the Available Work page and the first task in the case Admit will be listed as an available workitem Make a note of the case number Check out the Admit workitem Admit Weight 85 LK Diastolic BP 80 pk Sex F bk Patient ID 123456 i Height 1 8 x Heart Rate 72 Systolic BP 120 X Name Iva Payne is Age 21 Figure 30 Editing the Admit Workitem detail The Admit workitem simulates an admission to the Casualty department of a hospital where various initial checks are made of the patient You ll see that in Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 38 addition to the patient name and id specified earlier there are a number of fields containing some
7. having the Rules Editor notify the service to reselect the new worklet using the updated rule set see the Section 5 on the Rules Editor for more detail The process requires a user with administration authority to action the rejection request rather than allow all users access to update rule sets Note Rejecting a worklet selection or raising a new unexpected exception will automatically suspend the parent case until such time as the rejection or unexpected exception is actioned by an administrator Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 55 Worklet Service Define New External Exception for Case Microsoft Internet Explorer oles File Edit View Favorites Tools Help a Osx S BB GO Aseh Faoite O amp D3 B s http localhost 8080 workletService newCaseException case1D 33 Links Customize Links 4 Free Hotmail 4 windows Worklet Service The Power of Expressiveness Worklet Admin Tasks Workflow Specifications Kekke ditut YAWL Home Administrate Available Work Logout Define New Case Level Exception Case ID Specification ID 33 OrganiseConcert Please complete each of the fields below Proposed Title Equipment Lost in Transit Scenario We were expecting to receive all the band s equipment from Japan but it hasn t arrived and the shipper can t locate it We will have to hire new equipment for Brisbane Sydney at thi
8. including all those discussed in this manual Installing the Worklet Service 1 Extracting and Installing the Repository The repository needs to be installed first because the Service depends on its various components for its operation The repository has this structure a O logs O rules O rulesEditor O selected O worklets Figure 1 Worklet Repository Folder Structure S The logs folder is where the Service writes certain log files during its operation In particular the eventLog csv file logs the key events of the service when database persistence is disabled All are plain text files S The rules folder contains the sets of rules used during the selection and exception handling processes Rules files have an XML format Each YAWL specification that uses the service will have a corresponding rules file of the same name except with an extension of xrs XML rule set S The rulesEditor folder contains a tool that is used to manage and modify rule sets see Chapter 5 for a complete description of the Rules Editor S The selected folder contains a set of files in XML format that are essentially log files that capture the results of each selection process either via the Selection Service or through the selection of a compensating Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 3 worklet via the Exception Service These files have an xws extension XML Worklet Selection These files are used by the Rules
9. itemInfo String status elItem getChildText status return String valueOf isFinishedStatus status Notice again that the function has been declared as private static and returns a String value The first line of the function converts the String passed into the function to a JOOM Element and then extracts from that Element a value for status being one of the data attributes contained in the this variable It then calls another method defined in the Implementation section called isFinishedStatus private static boolean isFinishedStatus String status return status equals WorkItemRecord statusComplete status equals WorkItemRecord statusForcedComplete status equals WorkItemRecord statusFailed All methods defined in the Implementation section must also be declared as private static methods however they can have any return type so long as the value returned from the execute method back to the Worklet Service has been converted to a String value Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 59 Of course you are not restricted to querying the this variable as a WorkItemRecord it is passed simply as a JOOM Element that has been converted to a String and so can be queried via a number of different methods The objective of the RdrConditionFunctions class is to allow developers to easily extend the capabilities of the Worklet Service by providing the means to test for
10. CONSTRAINT EVENT Checking pre constraints for workitem 21 CancelStadium_3 o pre task constraints defined for task CancelStadium HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking pre constraints for workitem 21 Book_Ent_Centre_5 o pre task constraints defined for task Book_Ent_Centre HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 21 1 CancelStadium_3 o post task constraints defined for task CancelStadium HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking pre constraints for workitem 21 Tell_Punters_4 o pre task constraints defined for task Tell_Punters HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 21 2 Book_Ent_Centre_5 o post task constraints defined for task Book_Ent_Centre HANDLE CHECK CASE CONSTRAINT EVENT Checking constraints for end of case 21 o post case constraints defined for spec ChangeToMidVenue Worklet ran as exception handler for case 20 Exception process step 3 Action continue Target workitem 61 2006 09 12 13 13 59 468 2006 09 12 13413359 515 2006 09 12 13 13 59 531 2006 09 12 3713459531 2006 09 12 13 13 59 546 2006 09 12 13313259 750 2006 09 12 13213259 875 2006 09 12 13 13 559 953 2006 09 12 13 14 00 046 2006 09 12 13 14 00 046 2006 09 12 13 14 00 156 2006 09 12 13214200 171 DEBUG FO FO FO FO FO DEBUG FO FO FO FO FO Excep Excep Excep Excep Excep Excep Excep Excep Excep Excep Excep Excep
11. Editor to enable the addition of new rules for a specification The worklets folder contains the worklet specification files These files are YAWL specifications that are run as required by the service Several of the folders contain examples To install the repository first open workletService war in an unzipping tool e g 7 Zip Locate and extract workletRespository zip to a temporary directory I 7 Zip File Manager BAX File Edit Yiew Favorites Tools Help tev x i i C workletService war Name Packed Size Modified graphics OB 2006 08 26 20 24 isp OB 2006 08 26 20 24 E META INF 0B 2006 08 26 20 24 9 WEB INF 0B 2006 08 26 20 24 welcome htm 1494B 2006 08 26 20 24 i i 125K 2006 08 26 20 24 1 objectis selected 130K 130K 2006 08 26 20 24 Figure 2 Contents of the workletService war file Then simply extract the contents of workletRepository zip to a folder of your choice keeping the sub folder structure intact Once that is done the Service needs to be configured so that it can find the location of the repository 2 Configuring the Service The workletService war file should be copied to the webapps directory of your Tomcat installation if necessary refer to the YAWL Installation Manual for more information Then the file needs to be extracted to its own directory under webapps The easiest way to achieve this is to simply start Tomcat it will automatically extract install and start t
12. EnablePersistence parameter Save and close web xml Worklet Service installation is now complete However by default the Selection Service is enabled within the YAWL Engine but the Exception Service is not If you wish to enable the Exception Service proceed to Step 3 below 3 Enabling the Worklet Exception Service When YAWL Beta 8 is installed the Exception Service is configured as disabled in the YAWL Engine To enable the Exception Service a parameter has to be set in the YAWL Engine s web xml file Open the engine s web xml file in folder webapps vaw WEB INF Locate the parameter named EnableExceptionService to enable the Exception Service change the param value to true see Figure 4 Save and close web xml Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 5 lt PARAMS FOR EXCEPTION SERVICE gt lt context param gt lt param name gt EnableExceptionService lt param name gt lt param value gt true lt param value gt lt description gt Set this value to true to enable monitoring by an Exception Service specified by the URI param below Set it to false to disable the Exception Service lt description gt lt context param gt Figure 4 The YAWL Engine s web xml file detail The Exception Service uses extensions or hooks in the YAWL worklist handler to provide methods for interacting with the Service so if you have enabled the Service in the Engine as above you
13. Figure 22 shows the main Rules Editor screen with the new rule added in the correct place in the tree with the current case data becoming the Cornerstone Case for the new rule p3 Worklet Rules Editor lt Browse gt Casualty_Treatment zm File Rule Options Help 4 Q Bo Rule Type Selection Task Name Treat x RDA Tree Comerstone Case Rule 0 PatientID 98769067 f Rue 1 Sex F Rule 8 Rule 10 Rule 2 Rule 3 Rule 4 Rule 5 Rues DiastolicBP 110 Height 1 57 HeartRate 190 SystolicBP 165 Fracture false Age 66 Weight 107 Fever false Rash true Wound false Name Gammy Ticker m Selected Node Node ID 10 Parent Node ID E Condition HeartRate gt 175 Conclusion 1 select TreatHighHeartRate Description M worklet is used to treat patients with very high heart rates Figure 22 Main Screen after Addition of New Rule Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 30 Creating a New Rule Set and or Tree Set As mentioned previously it is not necessary to create tree sets for all of the rule types nor a rule tree for an item level rule type encompassing every task in a specification So most typically rule sets will have rules defined for a few rule types with some tasks left undefined remember that any events that don t have associated rules for that type of event are simply ignored It follows that ther
14. a particular tree of a rule set it is first necessary to open the rule set in the Rules Editor as described above Then click Rules on the top menu then Add or click the Add Rule toolbar button to open the initially blank Add Rule form Notice that the name of the opened rule set is shown in the title bar of the form and the rule type and task name that are currently selected on the main form have been transferred to the Add Rule form Thus to add a new rule to a rule tree that rule tree must first be selected on the main Rules Editor form before the Add Rule form is opened Every time the Worklet Service selects a worklet to execute for a specification instance a log file is created that contains certain descriptive data about the worklet selection process These files are stored in the selected folder of the worklet repository The data stored in these files are again in XML format and the files are named according to the following format CaseID_SpecificationID_RuleType_WorkItemID xws For example 12_CasualtyTreatment_Selection_Treat xws xws for Xml Worklet Selection The identifiers in each part of the filename refer to the parent specification instance not the worklet case instance Also the WorkItemID identifier will not appear for case level rule types So to add a new rule after an inappropriate worklet choice the particular selected log file for the case that was the catalyst for the rule addition must be located
15. also need to enable the extensions in the worklist To do so locate and open the worklist s web xml file in folder webapps worklist WEB INF Locate the context parameter named InterfaceX_BackEnd By default the entire parameter block is commented out To enable the Exception Service extensions to the worklist simply remove the comment tags shown in red in Figure 5 below Save and close web xml lt This param when available enables the worklet exception service add ins to the worklist If the exception service is enabled in the engine then this param should also be made available If it is disabled in the engine the entire param should be commented out gt lt lt context param gt lt param name gt InterfaceX_BackEnd lt param name gt lt param value gt http localhost 8080 workletService lt param value gt lt description gt The URL location of the worklet exception service lt description gt lt context param gt gt Figure 5 The YAWL Worklist s web xml file detail The Exception Service is now fully enabled and operational For information on how the Exception Service works and how to use it see Sections 4 and 6 4 Installing the Rules Editor The Worklet Rules Editor allows you to browse the rule sets of specifications add new rules to existing rule sets and add complete new rules trees to rule sets It is a NET based application so has the following requirements Ope
16. an account Time service allows tasks to be a timeout task let Dynamic Process Selection Service Figure 8 Associating a task with the Worklet Service Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 The list of task variables in Figure 8 also show that most variables are defined as Input Only this is because those values will not be changed by any of the worklets that may be executed for this task they will only be used in the selection process The last three variables are defined as Input amp Output so that the worklet can return or map back to these variables data values that are captured during the worklet s execution The dialog has a section at the bottom called YAWL Registered Service Detail It is here that the task is associated with the Worklet Service by choosing the Worklet Service from the list of available services Note that list of services will only be seen if Tomcat is currently running and it has those services installed Select the Worklet Service from the list That is all that s required to make the top level specification worklet enabled Next we need to create one or more worklet specifications to execute as substitutes for the worklet enabled task Worklet Specifications When the Casualty Treatment top level specification is executed the YAWL Engine will notify the Worklet Service when the worklet enabled Treat task becomes enabled The Worklet Service will then exa
17. define the actual function in the function definition section Here s the entire function Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 57 public static String max int x int y if x gt y return String valueOf x else return String valueOf y Notice that the function has been declared as private static and returns a String value Next the name of the function max has to be added as a String value to the _functionNames array in the header section of the code public static final String _functionNames max min isNotCompleted today Finally we need to map the function name to the execute method which acts as the interface between the class s functions and the Worklet Service The execute method receives as arguments the name of the function to execute and a HashMap containing the function s parameters all are passed as String values The execute method is essentially an if else if block the sub blocks of which call the actual functions defined This is the section of the execute method for the max function else if name equalsIgnoreCase max int x getArgAsInt args x int y getArgAsInt args y return max x y The first line checks to see if the name of the function passed to the execute method is max If it is the parameters passed with the function as String values in the HashMap args are converted to integer values an
18. displays graphically the new rule tree as it is being created New rule nodes can be added wherever there is a node on the tree that does not have a child node on both its true and false branches except the root node which can have a true branch only To identify possible locations to add a rule node special potential nodes can be seen in the RDR Tree panel called New True Node or New False Node These potential nodes are coloured yellow for easy identification To add a new rule select the yellow new rule node where you would like the rule to be added When you select a new rule node the various inputs for the new rule become enabled Refer to the Adding a New Rule section above for details of the types of operands and operators you can add as the condition of the new rule To add a conclusion to the new rule click the New button If the currently selected rule type is Selection a worklet can be added as a conclusion in the way described in the Adding a New Rule section If it is one of the exception rule types the New button will display the graphical Draw Conclusion dialog allowing you to build a sequence of tasks or primitives in an exception handling process explained in detail below When the conclusion sequence has been defined and the dialog closed a text based version of it will display in the Conclusion panel Once the new rule node has a valid condition and conclusion and optionally some corner
19. e if it has a status of Fired Enabled Executing or Suspended If it hasn t completed thus payment for the order has not yet been received then the conclusion will be executed as an exception handling process including the launching of the worklet SendReminder The SendReminder worklet consists of three tasks Send Request and the parallel tasks wait and Receive Reply the wait task in this specification is again associated with the Time Service and again for the purposes of the example waits for 5 seconds before timing out When the wait task times out the Exception Service is notified There is a single timeout rule for the Receive Reply task its condition is again isNotCompleted this but this time the rule s conclusion looks like this Condition jisNotCompleted this Conclusion 1 suspend case 2 run worklet CancelOrder 3 remove ancestorCases Figure 53 Rule detail for Receive Reply Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 53 When this conclusion is executed as an exception handling process the Available Work Screen in the YAWL worklist now looks like this Available Work Items iD Task Des on Status 30 Receive_Payment_3 Receive_Payment Suspended Sep 13 10 48 36 32 File Cancellation 3 File_Cancellation Enabled Sep 13 10 49 00 31 Receive_Reply_S Receive_Reply Suspended Sep 13 10 48 54 Figure 54 Available Work After CancelOrder Worklet Launched File Cancellation
20. enabled Figure 50 Available Work Items ID Task Description Status Enablement Time O 23 Buy M and Ms 5 Buy_M_and_Ms Enabled Sep 12 14 00 54 22 SellTickets_3 SellTickets Suspended Sep 12 13 40 04 Check Out l Reset Raise Exception Figure 50 Available Work Items after External Exception Raised Organise Refreshments informs the staff member responsible to buy a certain number of bags of M amp M s first workitem then to remove the candies of a specified colour before delivering them to the venue mapped in from the parent case Once the worklet has completed the parent case is continued Item level external exceptions can be raised from the Available Work screen by selecting the relevant workitem via the radio button to its left then clicking the Raise Exception button You will be taken to the Raise Item Level Exception screen where the procedure is identical to that described for case level exceptions except that the item level external exception triggers if any will be displayed External exceptions can be raised at any time during the execution of a case the way they are handled may depend on how far the process has progressed via the defining of appropriate rule tree or trees E Exception Timeout Example YAWL provides a Time Service which when a workitem is associated with it will check out the workitem wait until a pre defined time span has elapsed or a certain date time reac
21. ennonn anena e aia ia a 10 4 Using the Worklet Exception Service eessseeeesseeeessresssrresssreesserresssrressereessssresssrres 13 Exception TYPES onerar e Sessa ar ar O aa e aaa A aa Erea ea a AEA NS 14 Constraint EypES ma E a A AA Raa aus bagel alee anal aaa 14 Externally Triggered TypeSasi nine ae ihe a A Aa aR 14 TIMEOUT a crits cole se SETE E E AON E EE E A EE E Ea 15 ThA DOr ieor aea iea ae a e E oe Eea t E aS noe 15 Resource Unavailable rren oeaan eiei n e eaea a aa eodein aiee 15 Constraint Violations iena eae e a ee eae 15 Exception Handling Primitives eeeseeeeesessessessersssrerssrresssrrerssrresssrreesseresseeresssrress 15 5 Worklet Rule Sets and the Rules Editor seeeeessesessersssseessssressereerssrrerssrresssrresssrressee 18 Workl t Rule S tsie citi ee e e a e a a ented eae 18 The Rules Edit re ia o oaran etas E aE EAE EERE E N EE EEES 21 Browsing an Existing Rule Seto eee e atrae erae E Eae E E a E EOE KEREN 22 Th Toolbar e ere n a a a a a e anes O EE 23 Other Feature Ssss onne ste t ae eect ea ete I ah eels 24 Addin ga NEW RUIE c scscsveis tag cecetieds topstea gets deed a deeindes N a a a ai 25 Adding a Conclusion Selection Rule Type eeeeeeseeeeeseesessrersssreresrreessrresseereessrress 28 Dynamic Replacement of an Executing Worklet eeeeseeeeereesrrressrrrrserreessrree 29 Creating a New Rule Set and or Tree Set ce eeeeeeceeessececesenceeceeseeeceseeeeeesnneeeee
22. interact with each other in order to delegate work to signal the creation of process instances and workitems or to notify a certain event or a change of status of existing workitems Custom YAWL services are external applications that interact with the YAWL engine through XML HTTP messages via certain endpoints some located on the YAWL engine side and others on the service side Custom YAWL services are registered with the YAWL engine by specifying their location in the form of a base URL Once registered a custom service may send and receive XML messages to and from the engine More specifically Custom YAWL services are able to check out and check in workitems from the YAWL engine They receive a message when an item is enabled and therefore can be checked out When the Custom YAWL service is finished with the item it can check it back in in which case the engine will set the work item to be completed and proceed with the execution What is the YAWL Worklet Service The Worklet Dynamic Process Selection amp Exception Handling Service for YAWL comprises two distinct but complementary services a Selection Service which enables dynamic flexibility for YAWL process instances and an Exception Handling Service which provides facilities to handle both expected and unexpected process exceptions i e events and occurrences that may happen during the life of a process instance that are not explicitly modelled within the process at r
23. open the YAWL Editor and create a process specification in the usual manner Choose one or more tasks in the specification that you want to have replaced with a worklet at runtime Each of those tasks needs to be associated via the YAWL Editor with the Worklet Service For example Figure 7 shows a simple specification for a Casualty Treatment process In this process we want the Treat task to be substituted at runtime with the appropriate worklet based on the patient data collected in the Admit and Triage tasks That is depending on each patient s actual physical data and reported symptoms we would like to run the worklet that best handles the patient s condition Worklets may be associated with an atomic task or a multiple instance atomic task Any number of worklets can be associated with i e comprise the repertoire of an individual task and any number of tasks in a particular specification can be associated with the Worklet Service Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 8 YAWLEditor Specification Net Edit Elements Tools View Help Bel v a Ble a Casualty_Treatment H r 1 A AO e Triage Treat Discharge Figure 7 Example Top level Specification Here we want to associate the Treat task with the Worklet Service To do so right click on the task then select Task Decomposition Detail from the popup menu The Update Task Decomposition dialog is shown Figure 8 This dial
24. the case of multiple instance tasks a worklet is launched for each child workitem Because each child workitem may contain different data the worklets that substitute for them are individually selected and so may all be different The repertoire of worklets can be added to at any time as can the rules base used for the selection process Thus the service provides for dynamic ad hoc change and process evolution without having to resort to off system intervention and or system downtime or modification of the original process specification The Exception Service During every instance of a workflow process certain things happen off plan That is it doesn t matter how much detail has been built into the process model certain events occur during execution that affect the work being carried out but were not defined as part of the process model Typically these events are handled off system so that processing may continue In some cases the process model will be modified to capture this unforeseen event which involves an organisational cost downtime remodelling testing and so on The Worklet Dynamic Exception Handling Service or Exception Service provides the ability to handle these events in a number of ways and have the process continue unhindered Additionally once an unexpected exception is handled a certain way that method automatically becomes an implicit part of the process specification for all future instances of
25. the process which provides for continuous evolution of the process but avoiding the need to modify the original process definition The Exception Service uses the same repertoire of worklets and dynamic rules approach as the Selection Service The difference is that while the Selection Service is invoked for certain tasks ina YAWL process the Exception Service when enabled is invoked for every case and task executed by the YAWL engine and will detect and handle up to ten different kinds of process exception As part of the handling process a process designer may choose from various actions such as cancelling suspending restarting and so on and apply them at a workitem case and or specification level The Exception Service is extremely flexible and multi faceted and allows a designer to provide tailor made solutions to runtime process exceptions as described in the following pages Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 2 2 Installation Worklet Installation Package Within the YAWL web release YAWL Beta 8 Executable WebServer Version zip there is a file called workletService war this is the worklet web application component In addition to the custom service application files workletService war contains a file called workletRespository zip which contains a required set of directories where worklets and rules files are stored logs are written to and so on and a number of sample worklets and rule sets
26. tionService tionService tionService tionService tionService tionService tionService tionService tionService tionService tionService tionService Successful work item unsuspend 20 DoShow_4 HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 21 3 Tell_Punters_4 o post task constraints defined for task Tell_Punters Exception monitoring complete for case 21 HANDLE CHECK CASE CONSTRAINT EVENT Checking constraints for end of case 20 o post case constraints defined for spec OrganiseConcert HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 20 3 DoShow_4 o post task constraints defined for task DoShow Exception monitoring complete for case 20 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 62
27. Concert 22 l Launch Case Peset Z Figure 47 Workflow Specifications Screen OrganiseConcert case running The Case Viewer Screen appears with 4 buttons available if it only has two buttons the exception service has not been correctly enabled for the worklist review the installation section at the beginning of this document for details on Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 49 how to enable the service in the worklist Click on the Raise Exception button Figure 48 Case Viewer for 22 CaselID 22 SpecificationID OrganiseConcert Reject WorKe Figure 48 Case Viewer Screen The Raise Case Level Exception Screen is now displayed This screen is a member of a set of Worklet Service add in screens for the worklist note the worklet logo in the top left of the banner identifying it as a worklet add in screen Before this screen is displayed the Exception Service retrieves from the tule set for the selected case the list of existing external exception triggers if any for the case s specification See Figure 49 for the list of case level external triggers defined for the Organise Concert specification File Edit View Favorites Tools Osk O BB OD Asah eyravortes O O G ami E S Address http flocalhost 8080 workletService caseException caseID 22 m Eco Links customize Links Free Hotmail 2 windows Ta EET T Worklet Service The Power of Expressiveness Wor
28. Man 1 0 35 canvas Also the conclusion will be considered invalid if there are any nodes on the canvas that are not attached to the sequence when Save is attempted Use the Select Tool to move placed primitives around the canvas First select the Select Tool in the toolbox then click and drag a primitive to a new location The Align button will immediately align the nodes horizontally and equidistantly between the start and end nodes as in figure 26 The Clear button will remove all added nodes to allow a restart of the drawing process The Cancel button discards all work and returns to the previous form The Save button will save the conclusion and return to the previous form as long as the sequence is valid To delete a primitive from the canvas right click on the primitive and select Delete from the popup menu The Compensate primitive will when invoked at runtime execute a worklet as a compensation process as part of the handling process To specify which worklet to run for this sequence right click on the Compensate primitive and select Define Worklet from the popup menu The Choose Worklet dialog will appear identically to the Selection conclusion process allowing the selection of an existing worklet or the definition of a new worklet to run as a compensatory process Select the appropriate worklet to add it to the compensatory primitive Note that a sequence will be considered invalid if it contains a Compensate primit
29. The Worklet Custom Service for YAWL Installation and User Manual Beta 8 Release Worklet Custom Service Manual Beta 8 Worklet_Man 1 0 Document Control Date Author Version Change 18 Dec 2005 Michael Adams 0 1 Initial Draft 3 March 2006 Lachlan Aldred 0 1 1 Merged installation manual 9 October 2006 Michael Adams 1 0 Updated for Beta 8 and the Exception Service Preface This manual contains instructions for installing amp using the Worklet Dynamic Process Selection amp Exception Handling Custom Service for YAWL Each section describes one part in the process of setting up and using the Worklet Service It is probably best to work through the manual from start to finish the first time it is read This manual focuses on the practical use of the Worklet Service For those interested a more technical description of the inner operations of worklets and the rule sets that support them can be found here or a more concise version here All of the example specifications rule sets and so on referred to in this manual can be found in the worklet repository distributed with the service as part of the YAWL Beta 8 release This icon indicates a hands on method or instruction Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 ii Contents Document Control noren a cec E vans ep EERE vases feck ganas tv R Ae ES li Preface Gedra ste cee papa vaste cdeaa RE cave
30. TreatFever Specification Uploaded and Launched eeeeeeesseeeeeeeneeeeeeees 41 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 iv Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 43 Figure 44 Figure 45 Figure 46 Figure 47 Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 Figure 53 Figure 54 Figure 55 Figure 56 Figure 57 Test Fever Workitem detail ccccsesessessnessseenceasasaeaeaeaeeeeeeeeeeeeeeeeees 41 Treat Fever Workitem detail cccccsesesessssesssessscseseeaeseceeeeeeeeeeeeeeeeees 42 Discharge Workitem with Data Mapped from TreatFever Worklet 42 The wListMaker Specification eeeseccceesscecesesseeeceesaceeecesneeceseaceeeseneeeeees 43 Start of wListMaker Case with Three Bob Values Entered detail 43 Workitems from each of the 3 Launched Worklet Cases essecceeeseeeeees 44 Bob Specifications Loaded and Launched by the Worklet Service 45 The Show List Workitem Showing the Changes to the Data Values 45 The OrganiseConcert Specification csccccesescececesseeeceeseeeeceeneeecessnaeeeeesaes 46 The Book Stadium Workitem detail ccceccccceeceeeeseseeeeseseseseeeeeeeesesenenes 47 The Sell Tickets Workitem detail ccccccccecceeeeseeseeesseeeesesseeeseeeeeeseeeneees 47 Effective Com
31. Worklist s web xml file detail 0 ceccccececccccceeeeeeeneeeeeeeeeeseneeees 6 Figure 6 The Worklet Rules Editor eee eessececeessneeecessececeesscececesseeecessaaeeseeeneeeeneenees 7 Figure 7 Example Top level Specification 0 ccceessccccessececesenaeeecsseceeceesaeeecesseeeeeeenaes 9 Figure 8 Associating a task with the Worklet Service cceessecccessececeeeeeeeeeeneeeeeenees 9 Figure 9 The TreatFever Worklet ceeescccceessececeesseeeeceneeecessaceceeesaeeccsssaeeeesenaeeesesaas 10 Figure 10 Net level Variables for the TreatFever Specification cesseeceeesseeeeeeees 11 Figure 11 Example Handler Process in the Rules Editor eee eceeeseeecsesneeeeteeneeeeeenes 17 Figure 12 Excerpt of Rule Set file Casualty_Treatment x1 8 00 0 eeeeceeeeesneeeeeesneeeeeeees 18 Figure 13 Example Rule Tree Casualty Treatment spec eeeccceeeeseecceesneeeeeeseeeeeees 19 Figure 14 Rules Editor First Time Use Message 00 cceessccccessnceceeseneeeceeeeeeeetesaeeeeesnas 21 Figure 15 The Rules Editor Configuration Dialog ce eeeeeeseececeeeeneeeeeesneeeesenaeeeeeenes 22 Figure 16 Rules Editor Main Screen ou ceeeesecccesssceeesesneeecessaceeeessaeeccsssaeeeeeesaeeeeeenas 23 Figure 17 Add New Rule Form cc ceeesccccesssececessceeeseseeecessaceeeessaeeecsesaeeeesesaeeeeesaas 26 Figure 18 The Choose Worklet dialog 0 ec eeseccceesscceeseseneecessaceceeseaeeeesssa
32. _ Man 1 0 42 The specification is called wListMaker The only change made to the original List Maker specification was to associate the Verify List task with the Worklet Service using the YAWL Editor Figure 37 shows the specification List Maker Create list items done Verify list Show list Figure 37 The wListMaker Specification Y Go to the Administrate page and upload the wListMaker specification from the worklets folder of the worklet repository Then go to the Workflow Specifications page and launch an instance of wListMaker When the case begins enter 3 values for the Bob variable as shown in Figure 38 you will have to click the Insert after selected button twice to get three input fields Make sure you enter the values one two and three without the quotes and in any order Submit the form List Maker Master List Bob Insert after selected Delete selected Bob jone Bob two Bob three Figure 38 Start of wListMaker Case with Three Bob Values Entered detail Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 43 Check out and edit the Create List Items workitem Since the values have already been entered there is no more to do here so click the Submit button to continue The next task is Verify List which has been associated with the Worklet Selection Service Since this task is a multiple instance atomic task three child
33. ame TreatFever i NodelD f1 Parent Node ID 0 Rule Type CasePreConstraint z Condition Conclusion Task Name Ej RDA Tree New J Ruleo E New True Rule Description Comerstone Case Data Attribute Value Add gt Effective Composite Rule Ql Add Rule Cancel Figure 24 The Create New Rule Set Screen S The New Rule Node panel is identical to the panel on the Add New Rule form Here a condition and optional description can be entered and the conclusion for the new rule created or selected from the list depending on the rule type see below S The Cornerstone Case Data panel allows a set of cornerstone data for the new rule to be defined Add a variable name to the Attribute input and give it a value in the Value input then click the Add button to add it to the set of Cornerstone Case data Usual naming rules apply to the data attributes the attribute name must begin with an alpha character or underscore and contain no spaces or special characters S The Effective Composite Rule panel displays a properly indented text equivalent of the composite condition comprising the conditions of the selected node and all ancestor nodes back to the root node in other words the entire composite condition that must evaluate to true for the conclusion of the selected node to be returned Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 32 The RDR Tree panel dynamically
34. and loaded into the Rules Editor From the Add Rule screen click the Open button to load the selection information from the relevant selected log file The File Open dialog that displays will open in the selected folder of the repository Select the appropriate file for the case in question then click OK Note that the selected file chosen must be for an instance of the specification that matches the specification rule set loaded on the main screen in other words you can t attempt to add a new rule to a rule set that has no relation to the xws file opened here If the specifications don t match an error message will display Figure 17 shows the Add Rule form with the selected file 12_CasualtyTreatment_Selection_Treat xws loaded The Cornerstone Case panel shows the case data that existed for the creation of the original rule that resulted in the selection The Current Case panel shows the case data for the current case that is the case that is the catalyst for the addition of the new rule Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 25 The New Rule Node panel is where the details of the new rule may be added Notice that the id s of the parent node and the new node are shown as read only the Rules Editor takes care of where in the rule tree the new rule node is to be placed and whether it is to be added as a true child or false child node IMPORTANT Since we have the case data for the original rule and the
35. ands and operators of any complexity and sub expressions may be parenthesised The following operators are supported Precedence Operators Type 1 Arithmetic 2 3 gt lt ee aA Comparison l gt lt 4 amp Logical AND Logical OR Logical NOT All conditions must finally evaluate to a Boolean value i e true or false To make the condition for the new rule more appropriate the condition HeartRate 190 should be edited to read HeartRate gt 175 After defining a condition for the new rule the name of the worklet to be executed when this condition evaluates to true must be entered in the read only Conclusion field of the New Rule Node panel refer Figure 17 To select or create an appropriate worklet click the New button What happens next depends on whether the rule type for the tree you are adding the new rule to is of Selection type or one of the exception types Adding a conclusion for a Selection rule is explained below Refer to the Creating a New Rule Set and or Tree Set section below for details on adding a conclusion for the exception types Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 27 Adding a Conclusion Selection Rule Type For a Selection rule tree when the New button is clicked a dialog is displayed that comprises a drop down list containing the names of all the worklets in the worklets folder of the worklet reposi
36. ariables in the parent task and with a Usage of Output Only or Input amp Output will pass their data values back to the parent task when the worklet completes In Figure 10 it can be seen that the values for the PatientID Name and Fever variables will be used by the TreatFever worklet as display only values the Notes Pharmacy and Treatment variables will receive values during the execution of the worklet and will map those values back to the top level Treat task when the worklet completes Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 11 The association of tasks with the Worklet Service is not restricted to top level specifications Worklet specifications also may contain tasks that are associated with the Worklet Service and so may have worklets substituted for them so that a hierarchy of executing worklets may sometimes exist It is also possible to recursively define worklet substitutions that is a worklet may contain a task that while certain conditions hold true is substituted by another instance of the same worklet specification that contains the task Any number of worklets can be created for a particular task For the Casualty Treatment example there are initially five worklets in the repertoire for the Treat task one for each of the five primary conditions that a patient may present with in the Triage task Fever Rash Fracture Wound and Abdominal Pain Which worklet is chosen for the Treat task
37. as mapped the data attributes and values from the parent case Next check out the Book Ent Centre workitem by default it contains the data values mapped from the parent case Since we are moving the concert to a smaller venue change the values to match those in Figure 46 then submit the workitem Book Ent Centre venue Cost 50000 00 hk Seating 15000 x venue Name Ent Centre Figure 46 The Book Ent Centre Workitem detail The third workitem in the worklet Tell Punters is designed for the marketing department to advise fans and existing ticket holders of the change in venue Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 48 Check the workitem out from Available Work Notice that the values here are read only since this item is meant to be a notification only the person assigned does not need to change any values This is the last workitem in the worklet so when that is submitted the engine completes the case and notifies the Exception Service of the completion at which time the service completes the third and final part of the exception handling process i e continuing or unsuspending the Do Show workitem so that the parent case can continue Back at the Available Work screen the Do Show workitem is now shown as enabled and thus is able to be checked out Check it out now and notice that the data values entered in the worklet s Book Ent Centre workitem have been mapped back to the parent case D Excep
38. case data for the new rule to define a condition for the new rule it is only necessary to determine what it is about the current case that makes it require the new rule to be added That is it is only where the case data items differ that distinguish one case from the other and further only a subset of that differing data is relevant to the reason why the original selection was inappropriate For example there are many data items that differ between the two case data sets shown in Figure 17 such as PatientID Name Sex Blood Pressure readings Height Weight and Age However the only differing data item of relevance here is HeartRate that is the only data item that in this case makes the selection of the TreatRash worklet inappropriate ti Add New Rule 12_CasualtyTreatment_Selection_Treat m Rule Type Selection Task Name Treat Cornerstone Case Current Case PatientID 3457687 a PatientID 98769067 ja Sex M F DiastolicBP 80 iastoli Height 1 8 HeartRate 72 SystolicBP 120 SystolicBP 165 __ Cancel Fracture false Fracture false Age 66 Weight 107 Fever false Fever false Rash true Wound false Name Buster Legg M Name Gammy Ticker M New Rule Node Node ID 10 Parent Node ID 8 Condition New Conclusion Description Figure 17 Add New Rule Form Clicking on the line HeartRate 190 in the Current Case panel copies that line to the Condi
39. ch node having its condition evaluated along the way If a node s condition evaluates to True and it has a true child then that child node s condition is also evaluated If a node s condition evaluates to False and there is a false child then that child node s condition is evaluated When a terminal node is reached i e a node without any child nodes if its condition evaluates to True then that conclusion is returned as the result of the tree traversal if it evaluates to False then the last node in the traversal that evaluated to True is returned as the result The root node Rule 0 of the tree is always a default node with a default True condition and conclusion and so can only have a true branch ae condition gt tue er A aif default ae gonrnans 2 T gt e conclusion 1 N 2 A A Condition not satisfied Condition satisfied ees PA N 4 fe 7 AY u 4 Rash Tae HeatRate gt 190 TreatHighHeartRate Figure 13 Example Rule Tree Casualty Treatment spec TreatRash Effectively each rule node on the true branch of its parent node is an exception rule to the more general one of its parent that is a refinement of the parent rule while each rule node on the false branch of its parent node is an else rule to its parent or an alternate to the parent rule For example see the selection rule tree for the Casualty Treatment specification Figure 13 The condition part is th
40. ck to the parent case so that it may continue execution The full capabilities of the Exception Service are better described in the walkthroughs in Section 6 But before we consider the walkthroughs we must first look at exactly how the rule sets are formed and how they operate and how to use the Worklet Rules Editor to manage rule sets for specifications These topics are discussed in the next section Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 17 5 Worklet Rule Sets and the Rules Editor This section describes the structure and operation of worklet rule sets A tool has been designed to manage the creation and modification of rule sets for specifications called the Worklet Rules Editor The structure and operation of rule sets is best described by using the Rules Editor to display and manipulate them So a description of how to use the Rules Editor is interspersed in this section with the description of the rule sets themselves Again the Worklet Selection and Exception Services work in very similar ways but with some necessary differences In this section the discussion of rule sets applies to both services except where indicated Worklet Rule Sets Any YAWL specification may have an associated rule set The rule set for each specification is stored as XML data in a disk file that has the same name as the specification but with an xrs extension XML Rule Set All rule set files are stored in the rules fo
41. come to the Worklet Rules Editor Please enter the file paths to the resources listed in the next dialog Figure 14 Rules Editor First Time Use Message Clicking OK shows the Configuration dialog Figure 15 where the paths to resources the Rules Editor uses are to be specified Some default paths are shown but can be modified directly or by using the browse buttons where available The following paths must be specified S Worklet Service URI the URI to the Worklet Service The default URI assumes it is installed locally If it is remote to the computer running the Rules Editor then that URI should be entered ensuring it ends with workletService Worklet Repository the path where the worklet repository was installed The default path shown assumes the Rules Editor was started from the rulesEditor folder of the repository If it was started from another location specify the actual path to the repository by editing the path or browsing to the correct location Specification Paths the path or paths to locations on the local computer where YAWL specification files may be found The rules editor will search each of the paths provided for specifications for which rule sets may be created Multiple paths can be provided separated by semicolons 6 d S YAWL Editor the path and filename for the Y AWL Editor Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 21 4 Configure Paths Worklet Serv
42. d finally the max function is called its return value is passed back from the execute method to the calling Worklet Service The getArgsAsInt method called in the snippet above is defined in the Implementation section of the class s code It is here that you can create private methods that carry out the external work of the any functions defined as required The definition of isNotCompleted is slightly different since the parameter passed is the special variable this The this variable is essentially a WorkItemRecord that contains descriptors of the workitem the rule is testing enabling developers to write methods that test the values in the variable and act on those values Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 58 accordingly If it is for a case level rule this contains the case data for the instance invoking the rule Both versions of this are passed as a string ified JOOM Element format See the YAWL source code for more details of the WorkItemRecord class if required The execute method s sub block for the isNotCompleted function looks like this if name equalsIgnoreCase isNotCompleted String taskInfo String args get this return isNotCompleted taskInfo The block gets the this variable as a String from the args HashMap and then calls the actual isNotCompleted method public static String isNotCompleted String itemInfo Element eItem JDOMConversionTools stringToElement
43. depends on which of the five is given a value of True in the Triage task How the Worklet Service uses case data to determine the appropriate worklet to execute is described in Section 5 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 12 4 Using the Worklet Exception Service In the previous Section we saw how the Worklet Service adds dynamic flexibility to a usually static YAWL specification by substituting tasks with contextually chosen worklets at runtime The Worklet Exception Service leverages off the worklet framework to also provide support for the myriad exceptions that may occur during the execution of any process instance Every process instance no matter how rigidly structured will experience some kind of exception during its execution While the word exception conjures up ideas of errors or problems occurring within the executing process instance the meaning in terms of workflow processes is much broader exceptions are merely events or occurrences that for one reason or another were not defined in the process model It may be that these events are known to occur in a small number of cases but not enough to warrant their inclusion in the process model or they may be things that were never expected to occur or may be never even imagined could occur In any case when they do happen if they are not part of the process model they must either be handled off line before the process continues and the
44. e Current Task Name Rule Type Selection Task Name Treat Comerstone Case PatientID 3457687 Node s Rule 3 SystolicBP 120 L Cornerstone Rule 4 Fracture false Case Data Age 21 al Weight 85 0 Rule 3 Fever true Rash false Wound false Name Buster Legg bad Tree View Selected Node Node ID fi Parent Node ID jo Condition Feverstue 8 0 i lt ua a R s Selected Conclusion 1 select TreatFever Node s Details Figure 16 Rules Editor Main Screen The Toolbar The toolbar buttons replicate the functions available from the main menu S New Tree or Rule Set If there is no rules file currently open in the Editor this button displays the New Rule form to allow the creation of an entirely new rule set file for a specification i e one that does not yet have a rule set file defined If there is a rules file currently open in the Editor displays the New Rule form to allow the addition of new tree sets to the opened rule set file for rule types that have not yet been defined for that specification See the Creating a New Rule Set and or Tree Set section below for more details Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 23 Open Rules File Opens an existing rules file for browsing and or editing The title bar shows the name of the specification associated with the currently loaded rule set
45. e or all cases of a specification that triggered the exception Because the service allows you to define exception handlers for all exception events and even to add new handlers at runtime all exception events are able to be captured 7on system so that the handler is there for all future occurrences of a particular event for the same context And since the handlers are worklets the original parent process model only needs to contain the actual business logic for the process while the repertoire of handlers grows as new exceptions arise or different ways of handling exceptions are formulated Note that while the Selection Service is linked explicitly to tasks as defined in the YAWL process editor the Exception Service is either enabled or disabled on or off when it is enabled it manages exception handling for al instances executed by the engine there is no need to explicitly link a process to the service Also the Selection and Exception Services can be used in combination within particular case instances to achieve flexibility and exception handling simultaneously Please read the user manual for more information YAWL is distributed under the YAWL licence Done Local intranet Figure 28 Welcome Page for the Worklet Service A Selection Worklet Enabled Atomic Task Example The Casualty Treatment specification used in the previous sections of this manual is an example of a specification that contains an atomic task
46. e checked back in In the meantime the Worklet Service uploads the relevant specification for the worklet chosen as a substitute for the workitem and launches a new case for the specification When the worklet case completes the Worklet Service is notified of the case s completion and the service then checks the original workitem back into the Engine allowing the original process to continue Go to the Available Work page Instead of seeing the next workitem listed i e Treat we see that Test Fever the first workitem in the TreatFever process is listed in its place Figure 32 The TreatFever process has been chosen by the Worklet Service to replace the Treat workitem based on the data passed to the service 3 We have completed editing the Triage workitem and clicked the Submit button YAWL Home Administrate Checked Out Work Logout Welcome to YAWL admin Available Work Items iD Task Description Status Enablement Time O 3 3 Test Fever Test_Fever Enabled Dec 18 9 37 32 Figure 32 New Case Launched by the Worklet Service parent process Worklets run as completely different cases to the parent process but the Worklet Service keeps track of which worklets are running for which parent cases Go to the Workflow Specifications page to see that a Casualty Treatment case is still running and that the TreatFever specification has been loaded and it also has a case running Figure 33 e Note that the case id fo
47. e rule that is evaluated and the conclusion is the name of the worklet selected by that rule if the condition evaluates to true For example if the condition fever true Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 19 evaluates to true then the TreatFever worklet is selected via node 1 if it is false then the next false node is tested node 2 If node 2 is also false then node 3 is tested If node 3 evaluates to true then the TreatAbPain worklet is selected except if the condition in its next true node node 7 also evaluates to true in which case the TreatLabour worklet is selected One worklet rule set file is associated with each specification and may contain up to eleven sets of rule trees or tree sets one for selection rules and one for each of the ten exception types Three of the eleven relate to case level exceptions i e CasePreConstraint CasePostConstraint and CaseExternalTrigger and so each of these will have only one rule tree in the tree set The other eight tree sets relate to the workitem level seven exception types plus selection and so may have one rule tree for each workitem in the specification that is the tree sets for these eight rule types may consist of a number of rule trees It is not necessary to define rules for all eleven types for each specification You only need to define rules for those types that you want to handle any exception types that aren t defined in the rul
48. e set file are simply ignored So for example if you are only interested in capturing pre and post constraints at the workitem level then only the ItemPreConstraint and ItemPostConstraint tree sets need to be defined i e rules defined within those tree sets In this example any Timeout exception events that occur during the execution of the specification would be ignored by the Exception Service Of course rules for a Timeout event could be added later if required as could any of the other types not yet defined in the rule set Referring back to Figure 12 notice that the file specifies a Selection rule tree for the Treat task The second ruleNode contains a condition Fever True and a conclusion of TreatFever Thus when the condition Fever True evaluates to true the worklet TreatFever is chosen as a substitute for the Treat task Notice also that each rule node except the first has a parent and may have two child nodes a true child and a false child To summarise the hierarchy of a rule set from the bottom up Rule Node contains the details condition conclusion id parent and so on of one discrete ripple down rule Rule Tree consists of a number of rule nodes in a binary tree structure Tree Set a set of one or more rule trees Each tree set is specific to a particular rule type timeout selection etc The tree set of a case level exception rule type will contain exactly one tree The tr
49. e set is queried for both the wait task and the parallel Receive Payment workitem There is a tree defined for the Receive Payment task with a single rule see Figure 52 Notice the rule s condition isNotCompleted this S isNotCompleted is an example of a defined function that may be used as or as part of conditional expressions in rule nodes S this is a special variable created by the Worklet Service that refers to the workitem that the rule is defined for and contains amongst other things all of the workitem s data attributes and values Tip The Worklet Service provides developers with an easily extendible class where functions can be defined and then used in conditions See Appendix A for more information about defining functions Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 52 Ge Worklet Rules Editor lt Browse gt TimeoutTest3 J o File Rule Options Help hQ A8 Rule Type TimeDut Task Name Receive Payment Rule 0 amp Rule 1 Cost 200 Paid False RDR Tree Cornerstone Case Selected Node Node ID f1 Parent Node ID 0 Condition jisNotCompleted this Conclusion 1 suspend workitem 2 run worklet SendReminder 3 complete workitem Description No payment received after timeout Figure 52 Rules Editor Showing Single Timeout Rule for Receive_Payment Task In this case the condition tests if the workitem Receive_Payment has not yet completed i
50. e will be occasions where you will want to add a new tree set to a rule set for a previously undefined rule type or add a new tree for a previously undefined task to an existing tree set Also when a new specification has been created a corresponding base rule set will also need to be created if you want to handle selections and exceptions for the new specification For each of these situations the Rules Editor provides a New Rule form which allows the definition of new rule trees with any number of rule nodes for existing tree sets where there is a task of the specification that has not yet had a tree defined for it within the tree set the definition of new tree sets for specifications that have not yet had a tree set defined for a particular rule type and entirely new rule sets for specifications that have not yet had a rule set created for them The use of the New Rule form varies slightly depending on whether it is working with a new rule set or an existing rule set This section will describe the features of the New Rule form for adding a new rule set and describe how the process differs for existing rule sets as necessary To create a new rule set click the File menu then select New or click the New Rule toolbar button To add a new rule set make sure there is no rule set file currently open in the Editor If you are creating a new rule set a dialog will display asking for the path and file name of the specification for whic
51. ee set of an item level rule type will contain one rule tree for each task of the specification that has rules defined for it not all tasks in the specification need to have a rule tree defined S Rule Set a set of one or more tree sets representing the entire set of rules defined for a specification Each rule set is specific to a particular specification A rule set will contain one or more tree sets one for each rule type for which rules have been defined Of course to maintain a rule set of any complexity by directly editing the XML in a rule set file would be daunting to say the least To make things much easier a Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 20 Rules Editor tool has been developed and can be found in the rulesEditor folder of the worklet repository It can be run directly from there no further installation is required depending on the requirements below The Rules Editor The Worklet Rules Editor allows for the addition of new rules to existing rule sets of specifications and the creation of new rule sets It is a NET based application so has the following requirements Operating System Windows 98SE or later The Microsoft NET framework any version If you don t have the framework installed it can be downloaded free from Microsoft When the Rules Editor is run for the first time the following dialog is displayed Rules Editor First Time Configure 1 Wel
52. eeeesesaeeeeesnes 28 Figure 19 The New Rule Node Panel after a New Rule has been Defined 0 29 Figure 20 Message Dialog Offering to Replace the Running Worklet eee 29 Figure 21 Result of Replace Request Dialog e eee ecceeessececessceeeeesneeceeeeaeeeesesaeeeeenas 30 Figure 22 Main Screen after Addition of New Rule eec ec eeeesccceessneeeeeeeeeeeesesaeeeeeenes 30 Figure 23 The Specification Location Dialog c eee seceeesseeecessnceeeeesneeeessseeeeesesaeeeeeenes 31 Figure 24 The Create New Rule Set Screen e eee eeccceesssececessaceceeesaeecceesaeeeesssaeeeeeenas 32 Figure 25 Creating a New Rule Tree eee eesecccsessceeeseseeecessaceceeesaeeecsesaeeeesesaeeeeenas 33 Figure 26 The Draw Conclusion Dialog ceeeceeessccceseseeeecesssceeeeseneeeessnaeeeesesaeeeeesaes 35 Figure 27 A Conclusion Sequence shown as Text detail eee eeeesceccseeneeeeeesneeeeeenes 36 Figure 28 Welcome Page for the Worklet Service ce eeeeeeeseeeceeesneeeeeseneeeeeesaeeeeeenes 37 Figure 29 Launching a Casualty Treatment Case detail eee eeeeseecceesneeeeeeeneeeeeenes 38 Figure 30 Editing the Admit Workitem detail eeeececeseneeceeeeneeeeeesteeeeessaeeeeenes 38 Figure 31 Editing the Triage Workitem detail ee eeeeecesenccceeesneeeceesaeeeesesaeeeesaas 39 Figure 32 New Case Launched by the Worklet Service e ee eeeeccceessneeeeeeeneeeeeeseeeeeenes 40 Figure 33
53. es 31 Drawing a Conclusion Sequence ssseesesseeseesersssrerssrresssreersssrersstresssreessssreesseres 35 6 Walkthrough Using the Worklet Service ccceeeesseccesesceecesnaeeceeseneeeeestaeeeeeenacees 37 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 iii A Selection Worklet Enabled Atomic Task Example c ccesssceeeseeseeeeeseeees 37 B Selection Worklet Enabled Multiple Instance Atomic Task Example 42 C Exception Constraints Example eessccccssssceceseseececessnceeeceseeecesseeeeeenneeeeees 46 D Exception External Trigger Example eeecccceessececeeeneeeceeseeeceseneeeeseseeeeees 49 E Exception Timeout Example ernier erso anneer sata riers anaia idis 51 F Rejecting a Worklet and or Raising a New External Exception 54 Appendix A Defining New Functions for Rule Node Conditions eeceeeeeeeeeeeeeeees 57 Appendix B Sample Log generated by Walkthrough C eee eeeesceeessneeeeeeneeeeeeenaeees 61 Figures Figure 1 Worklet Repository Folder Structure eee eceeescceceesseeeeeesseeeceesaaeeeeeeneeeeeseaaes 3 Figure 2 Contents of the workletService war file 2 0 0 0 eesceecessneeeeeesseeeceeeneeeeeeeneeeeteesees 4 Figure 3 The Worklet Service s web xml file detail cccecccccccceeeeeseneeeeeeeeeesetneaees 5 Figure 4 The YAWL Engine s web xml file detail 00 seceesseeeeceeseeeeeeeneeeeeeenees 6 Figure 5 The YAWL
54. et enabled tasks each with an associated rule set and a number of associated worklets This section will step through the execution of several of these examples The first two examples feature the Selection Service the remainder the Exception Service Knowledge of how to use the YAWL system is assumed Before we begin make sure the Worklet Service is correctly installed and operational and then log into the YAWL system The easiest and best way to ensure the Worklet Service in on the air is to go to the YAWL Administrate page and click on the Worklet Service s URI link If all s well the service s welcome page will be displayed Figure 28 The Worklet Service for YAWL Microsoft Internet Explorer Je Ele Edit yiew Favorites Tools Help a Osk O BG seach grates 6 3 M O RD Address http flocalhost 8080 workletService ib v Eco Links Customize Links Free Hotmail Windows 8 Windows Marketplace 4 Windows Media 2 Log In OMe m The Power of Expressiveness Welcome to the Worklet Dynamic Process Selection and Exception Handling Service for YAWL This service provides two discrete but related features A dynamic selection service and a dynamic exception handling service The Selection Service provides the ability to substitute a workitem in a YAWL process with a dynamically selected worklet a discrete YAWL process that acts as a sub net for the task A repertoire or catalog of worklets is ma
55. form a particular task at runtime while sub nets are statically assigned at design time Also worklets can be added to the repertoire at any time during the life of a specification even while instances are running So rather than being forced to define all possible branches in a specification when it is first defined the Worklet Service allows you to define a much simpler specification that will evolve dynamically as more worklets are added to the repertoire for a particular task as different contexts arise The first thing you need to do to make use of the service is to create a number of YAWL specifications one which will act as the top level or manager or parent specification and one or more worklets which will be dynamically substituted for particular top level tasks at runtime The YAWL Editor is used to create both top level and worklet specifications A knowledge of creating and editing YAWL specifications and the definition of data variables and parameters for tasks and specifications is assumed For more information on how to use the YAWL Editor see the YAWL Editor User Manual Before opening the YAWL Editor make sure that the Worklet Service is correctly installed and that Tomcat is running see Section 2 of this document and or the YAWL Engine Installation Manual for more information First a top level specification needs to be defined Top level or Parent Specifications To define a top level specification
56. ger available S If itis an item level tree and all tasks now have trees defined for them for the selected rule type i e this was the final task of the specification for which a tree has been defined the rule type that the tree represents will be removed from the Rule Type list This approach ensures that rule trees can only be added where there are currently no trees defined for the selected specification Once the tree is added the form resets to allow the addition of another new tree as required by repeating the process above for a new rule type or rule type task name for item level trees After you have completed adding trees click the Save amp Close button to save all 8 the additions to the rule set file The Rules Editor will return to the main form Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 34 where the additional trees will immediately be able to be browsed IMPORTANT No additions will be actually saved until the Save amp Close button is clicked this is to allow you the option to discard all additions if you wish by clicking the Cancel button That is cancelling returns to the main Editor form and discards ALL additions for the session Save amp Close returns to the main form and saves all additions Drawing a Conclusion Sequence As mentioned in the Adding a New Rule section adding a conclusion to a Selection rule is simply a matter of choosing a worklet from the list or creating a new w
57. h the rule set is being created Figure 23 E Specification Location Please select or enter the path to the specification file that the new rule set will describe Specification File C worklets repository worklets T reatFever xml ey OK Cancel Figure 23 The Specification Location Dialog Figure 24 shows the Create New Rule Set form The form allows you create a rule set one rule tree at a time for the selected specification rule type and task name On this form The Process Identifiers panel is where the names of the specification rule type and task name for the new tree are defined The Specification Name input is read only for new rule sets it is the specification chosen via the Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 31 Specification Location dialog Figure 23 for existing rule sets it is the specification for the rule set currently loaded into the Rules Editor The Rule Type drop down list contains all of the available rule types i e all the rule types for which no or incomplete tree sets exist For new rule sets all rule types are available The Task Name drop down list contains all the available tasks for the selected rule type i e tasks for which no tree exists in the tree set for this rule type The Task Name list is disabled for case level rule types p3 Worklet Rules Editor Create New Rule Set l Process Identifiers New Rule Node Specification N
58. he Worklet Service Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 4 Once the service is fully extracted and installed there are a couple of minor configuration tasks to complete Open the service s web xml file in folder webapps workletService WEB INF in any text editor Locate the parameter named Repository and change its param value to the path where you installed the worklet repository The value should include the folder repository and end with a slash as shown in Figure 3 below lt context param gt lt param name gt Repository lt param name gt lt param value gt C Worklets repository lt param value gt lt description gt The path where the worklet repository is installed lt description gt lt context param gt lt context param gt lt param name gt EnablePersistence lt param name gt lt param value gt false lt param value gt lt description gt true to enable persistence and logging falset to disable lt description gt lt context param gt Figure 3 The Worklet Service s web xml file detail If you have enabled database persistence for the YAWL Engine if necessary see the YAWL Install Manual for details about enabling persistence for the YAWL Engine then persistence should also be enabled for the Worklet Service so that case data for running processes can be persisted across Tomcat sessions To enable persistence change the param value to true for the
59. he worklet drop down list Click the OK button to confirm the selection and close the dialog Figure 19 shows the New Rule Node panel after the definition of the example new rule has been completed A value in the Description field is optional but recommended Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 28 New Rule Node Node ID 10 Parent Node ID 8 Condition HeartRate gt 175 Conclusion 1 select TreatHighHeartR ate New Description This worklet is used to treat patients with very high heart rates Figure 19 The New Rule Node Panel after a New Rule has been Defined Once all the fields for the new rule are complete and valid click the Save button to add the new rule to the rule tree Dynamic Replacement of an Executing Worklet Remember that the creation of this new rule was triggered by the selection and execution of a worklet that was deemed an inappropriate choice for the current case So when a new rule is added you are given the choice of replacing the executing inappropriate worklet instance with an instance of the worklet defined in the new rule After the Save button is clicked a message similar to the Figure 20 is shown providing the option to replace the executing worklet using the new rule The message also lists the specification and case id s of the original work item and the name and case id of the running worklet instance Replace running worklet O Do you wish t
60. hed then check the item back in Effectively the time Service allows a workitem to act as a timer on a process branch typically one or more workitems execute in parallel to the time service workitem If the deadline is reached a timeout occurs for that item Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 51 When a workitem times out the Engine notifies the Exception Service and informs it of all the workitems running in parallel with the timed out item Thus rule trees can be defined to handle timeout events for all affected workitems including the timed out item itself The specification Timeout Test 3 gives an example of how a timeout exception may be handled Figure 51 Upload the specification via the Administrate screen and then launch the case Timeout Test 3 Fill Order Bresette auth pei Archive Receive Payment Figure 51 The Timeout Test 3 Specification The first workitem Fill Order simulates a basic purchase order for a bike Check out the Fill Order workitem accept the default values and submit it Once the order has been filled the process waits for payment to be received for the order before it is archived The wait task is associated with the Time Service and so merely waits for some time span to pass For the purposes of this example the wait time is set to 5 seconds While the deadline is reached the Engine notifies the Exception Service of the timeout event The timeout tre
61. ice URI http localhost 8080 workletService Worklet Repository C Worklets repository ey Specification Paths C yawhSpecs D 4bin is YAWL Editor C Syawledito YAW LE ditor 4 jar 2 Cancel Figure 15 The Rules Editor Configuration Dialog Some checks will take place to make sure the paths are valid and you will be asked to correct any that are not Once the configuration is complete the main screen will appear This screen allows you to view each node of each rule tree defined for a particular specification From this screen you can also add new rules to the current rule set create new tree sets for an existing rule set and create entirely new rule sets for new specifications Browsing an Existing Rule Set To load a rule set into the Rules Editor click on the File menu then select Open or click on the Open toolbar button The File Open Dialog will open with the rules folder of the repository selected Select the file you wish to open and then click OK Figure 16 shows the main screen with the rule set for the Casualty Treatment specification loaded On this screen you may browse through each node of a rule tree set and view the various parts of each node The main features of the screen are explained below Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 22 oe Worklet Rules Editor lt Browse gt Casualty_Treatment File Rule Bo Options Help Current Rule Typ
62. iid oe SS Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 16 Compensate run a compensatory process i e a worklet Depending on previous primitives the worklet may execute simultaneously to the parent case or execute while the parent is C suspended or even removed The primitives Suspend All Cases Continue All Cases and Remove All Cases may be edited so that their action is restricted to ancestor cases only Ancestor cases are those in a hierarchy of worklets back to the parent case that is where a case invokes a worklet which invokes another worklet and so on An example of a definition of an exception handing process in the Rules Editor is below E Worklet Rules Editor lt New Conclusion gt BAX m TIEN Jam a An vw it ww Save Clear Cancel Figure 11 Example Handler Process in the Rules Editor When invoked this handler will suspend the current case then run a compensating worklet then continue execution of the case In the same manner as the Selection Service the Exception Service also supports data mapping from a case to a compensatory worklet and back again For example if a certain variable has a value that prevents a case instance from continuing a worklet can be run as a compensation during which a new value can be assigned to the variable and that new value mapped ba
63. intained Each time the service is invoked for a workitem a choice is made from the repertoire based on the data passed with the workitem using a set of rules to determine the most appropriate substitution The workitem is checked out of the YAWL engine then the selected worklet is launched as a separate case The data inputs of the original workitem are mapped to the inputs of the worklet When the worklet has completed its output data is mapped back to the original workitem which is then checked back into the engine allowing the original process to continue Worklets can be substituted for atomic tasks and multiple atomic tasks In the case of multiple tasks a worklet is launched for each child workitem Because each child workitem may contain different data the worklets that substitute for them are individually selected and so may all be different The Exception Service leverages off the worklet framework to also provide support for the myriad exceptions that may occur during the execution of any process instance The service addresses the traditional problems of exception events occurring during the execution of rigidly defined static process instances by allowing you to define worklets that will act as exception handling processes for parent workflow instances when certain events occur Rules are defined in much the same way as for the Selection Service but with added features that enable you to pause resume cancel or restart the task cas
64. is the first task of the Cancel Order worklet What we now have is a hierarchy of worklets case 30 TimeoutTest3 is suspended pending completion of worklet case 31 Send Reminder which itself is suspended pending completion of worklet case 32 Cancel Order Worklets can invoke child worklets to any depth Notice the third part of the handling process remove ancestorCases Ancestor Cases are all cases from the current worklet case back up the hierarchy to the original parent case that began the exception chain as opposed to allCases which refers to all currently executing cases of the same specification as the case which generates the exception So when the Cancel Order worklet completes the Send Reminder case and the original parent Timeout Test 3 are both cancelled by the Exception Service F Rejecting a Worklet and or Raising a New External Exception The processes involved in rejecting a worklet launched either as a result of the Selection or the Exception Service and raising a new external exception that is an external exception which has not yet been defined formally an unexpected exception are virtually identical and so are discussed together in this section When the service launches a worklet it selects the most appropriate one based on the current case context and the current rule set for the parent case As discussed previously in this manual there may be occasions where the selected worklet does not best hand
65. ive for which a worklet has not yet been defined The primitives SuspendAllCases RemoveAllCases and ContinueAllCases may be limited to ancestor cases only by right clicking on primitives of those kinds and selecting Ancestor Cases Only from the popup menu Ancestor hierarchies occur where a worklet is invoked for a case which in turn invokes a worklet and so on When a primitive is limited to ancestor cases it applies the primitive s action to all cases in the hierarchy from the current case back to the original parent case rather than all running cases of the specification IMPORTANT No validation is done for the defined sequence besides that described above It is up to the designer of the sequence to ensure it makes sense for example that it doesn t try to continue a case it has previously removed When a valid sequence is saved you will be returned to the previous form i e either the Add Rule or New Rule form depending on where you are in the Editor The conclusion will be displayed textually as a sequential list of tasks Figure 27 for example Conclusion 1 suspend workitem 2 run worklet SendReminder 3 continue workitem Figure 27 A Conclusion Sequence shown as Text detail Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 36 6 Walkthrough Using the Worklet Service The worklet repository that comes with the Worklet Service release contains a number of example specifications with workl
66. ked explicitly to tasks as defined in the YAWL Editor and thus available whenever a worklet enabled task is executed the Exception Service is either enabled or disabled on or off when it is enabled it manages exception handling for all process instances executed by the engine explicitly linking a task or process to the service is not required Also the Selection and Exception Services can be used in combination within particular case instances to achieve dynamic flexibility and exception handling simultaneously Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 13 Exception Types This section introduces the 10 different types of exception that have been identified seven of which are supported by this version of the Worklet Service Some are related while others are more distinct Later sections will show examples of each of these When the Exception Service is enabled it is notified whenever any of these exception types occur for every process instance executed by the YAWL Engine by various means The Exception Service maintains a set of rules described in detail in Section 5 that are used to determine which exception handling process if any to invoke If there are no rules defined for a certain exception type for a specification the exception event is simply ignored by the service Thus you only need to define rules for those exception events that you actually want to handle for a particular specification Constrain
67. kfi YAWL Home Administrate arfa Available Work Checked Out Work Logout Specifications Raise Case Level Exception Case ID Specification ID 22 OrganiseConcert Select the type of exception that has occurred Support Act Breakup O Singer Tired and Emotional Guitarist Refused Visa Band Broken Up Ticket Sales Better than Expected Band Requests Backstage Refreshments New External Exception Submit Done 2 Local intranet Figure 49 Raise Case Level Exception Screen Organise Concert example Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 50 This list contains all of the external triggers either conceived when the specification was first designed or added later as new kinds of exceptional events occurred and were added to the rule set Notice that at the bottom of the list the option to add a New External Exception is provided that option is explained in detail in Walkthrough F For this example let s assume the band has requested some refreshments for backstage Select that exception trigger and submit the form When that exception is selected the conclusion for that trigger s rule is invoked by the service as an exception handling process for the current case You are immediately taken to the Available Work form where it can be seen that the parent case has been suspended and the first workitem of the compensatory worklet Organise Refreshments has been
68. lder of the worklet repository For example the file Casualty_Treatment xrs contains the worklet rule set for the Casualty_Treatment xml YAWL process specification Figure 12 shows an excerpt from that file lt ruleNode gt lt pre gt lt case gt lt constraints gt lt selection gt lt task name Treat gt lt ruleNode gt lt id gt O lt id gt lt parent gt 1 lt parent gt lt trueChild gt 1 lt trueChild gt lt falseChild gt 1 lt falseChild gt lt condition gt True lt condition gt lt conc lusion gt null lt conclusion gt lt cornerstone gt lt cornerstone gt lt description gt root level default node lt description gt lt ruleNode gt lt ruleNode gt lt id gt 1 lt id gt lt parent gt 0O lt parent gt lt trueChild gt 8 lt trueChild gt lt falseChild gt 2 lt falseChild gt lt condition gt Fever true lt condition gt lt conclusion gt lt _1 gt lt action gt select lt action gt lt target gt TreatFever lt target gt ae lt conclusion gt lt cornerstone gt Figure 12 Excerpt of Rule Set file Casualty_Treatment xrs Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 18 A rule set for a specification consists of a collection of rule trees Each rule tree represents a set of modified Ripple Down Rules RDR which maintains a rule node hierarchy in a binary tree structure When a rule tree is queried it is traversed from the root node of the tree along the branches ea
69. le the current case s context perhaps because of a new business rule or a more efficient method of achieving the goal of a task being found In any event a worker may choose to reject the worklet that was selected IMPORTANT The rejection of a selected worklet is a legitimate and expected occurrence Each rejection allows for the addition of a new exception rule or a rule on the true branch of its parent thus creating a learning system where all events are handled on line When the new rule is added as a result of the rejection it will return the correct worklet for every subsequent case that has a similar context Thus rejecting a worklet actually refines the rule set for a specification To reject a selected worklet go to the Workflow Specifications screen and click on the case id of the worklet you wish to reject At the Case Viewer screen click the Reject Worklet button see Figure 48 You will be redirected to the Reject Worklet Selection screen another Worklet Service add in screen Figure 55 This Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 54 screen displays the Specification and Case ID for the selected worklet Enter a proposed title or name for the new worklet and an explanation of reason for the rejection in plain text and then submit the form E Worklet Service Reject Worklet Selection Microsoft Internet Explorer i Vos File Edit View Favorites Tools Help ay Qe O BBG Asah geravo
70. medical data about the patient Each field has some default data to save time but you may edit any fields as you wish Figure 30 When done click the Submit button Triage task simulates that part of the process where a medical practitioner asks a patient to nominate their symptoms You ll see that the patient s name and id have again been displayed for identification purposes in addition to 5 fields which approximate the medical problem One field should be set to True the others to False Fa Go back to the Available Work page and check out the next workitem Triage The Let s assume the patient has a fever Set the Fever field to True the rest to False and then submit it Figure 31 Triage Patient ID 123456 Fever true O false Rash Otrue false wound O true false Name Iva Payne x Abdominal Pain true false Fracture Otrue false Figure 31 Editing the Triage Workitem detail There is nothing special about the first two tasks in the process they are standard YAWL tasks and operate as expected However the next task Treat has been associated using the YAWL Editor with the Worklet Selection Service The Treat task simulates that part of the process that follows the collection of patient data and actually treats the patient s problem Of course there are many medical problems a patient may present with and so there are just as many treatments and some treatment method
71. mine the data in the task and use it to determine which worklet to execute as a substitute for the task Any or all of the data in the task may also be mapped to the selected worklet case as input data Once the worklet instance has completed any or all of the available output data of the worklet case may be mapped back to the Treat task to become its output data and the top level process will continue A worklet specification is a standard YAWL process specification and as such is created in the YAWL Editor in the usual manner Each of the data variables that are required to be passed from the parent task to the worklet specification need to be defined as net level variables in the worklet specification Figure 9 shows a simple example worklet to be substituted for the Treat top level task when a patient complains of a fever F TreatFever Test Fever Treat Fever Figure 9 The TreatFever Worklet In itself there is nothing special about the TreatFever specification Even though it will be considered by the Worklet Service as a member of the worklet repertoire and may thus be considered a worklet it is a standard YAWL specification and Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 10 as such may be executed directly by the YAWL engine without any reference to the Worklet Service As mentioned previously those data values that are required to be mapped from the parent task to the worklet need to be defi
72. n 1 0 HANDLE CHECK CASE CONSTRAINT EVENT Checking constraints for start of case 20 of specification OrganiseConcert o pre case constraints defined for spec OrganiseConcert HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking pre constraints for workitem 20 BookStadium_5 o pre task constraints defined for task BookStadium HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking pre constraints for workitem 20 SellTickets_3 o pre task constraints defined for task SellTickets HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 20 1 BookStadium_5 o post task constraints defined for task BookStadium HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking pre constraints for workitem 20 DoShow_4 Workitem 20 DoShow_4 failed pre task constraints Invoking exception handling process for item 20 DoShow_4 Exception process step 1 Action suspend Target workitem Successful work item suspend 20 DoShow_4 Exception process step 2 Action compensate Target ChangeToMidVenue Worklet specification ChangeToMidVenue is already loaded in Engine Launched case for worklet ChangeToMidVenue with ID 21 HANDLE CHECK WORKITEM CONSTRAINT EVENT Checking post constraints for workitem 20 2 SellTickets_3 o post task constraints defined for task SellTickets HANDLE CHECK CASE CONSTRAINT EVENT Checking constraints for start of case 21 of specification ChangeToMidVenue o pre case constraints defined for spec ChangeToMidVenue HANDLE CHECK WORKITEM
73. nd selection rules being defined within the same rule set Directly following the pre case event the Engine notifies the Service of a PrelItemConstraint for the first workitem in the case in this case Book Stadium The pre item constraint event occurs immediately the workitem becomes enabled Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 46 i e ready to be checked out or executed Like pre case constraint rules pre item rules can be used to ensure workitems have valid data before they are executed The entire set of case data is made available to the Exception Service thus the values of any case variables may be queried in the ripple down rules for any exception type rule While there are pre item constraint rule trees defined in the rule set there are none for the Book Stadium task so this event is also ignored by the service The Book Stadium workitem may be checked out in the normal fashion This workitem captures the seating capacity cost and location of the proposed rock concert These may be changed to any valid values but for the purposes of this example just accept the default values as given Figure 43 Book Stadium venue Cost 100000 00 Seating 25000 venue Name ANZ Stadium Figure 43 The Book Stadium Workitem detail When the workitem is submitted a PostItemConstraint event is generated by the Engine There are no post item constraint rules for this workitem so again the event is just ign
74. ned as net level variables in the worklet specification Figure 10 shows the net level variables for the TreatFever task Update Net Decomposition TreatFever Net Decomposition Label TreatFever Net Decomposition Variables Name Type Usage Fever boolean Input Only Treatment string Input amp Output Notes string Input Output PatientID string Input Only Name string Input Only Pharmacy string Input amp Output Cancel Figure 10 Net level Variables for the TreatFever Specification Note the following Only a sub set of the variables defined in the parent Treat task see Figure 8 are defined here It is only necessary to map from the parent task those variables that contain values to be displayed to the user and or those variables that the user will supply values for to be passed back to the parent task when the worklet completes The definition of variables is not restricted to those defined in the parent task Any additional variables required for the operation of the worklet may also be defined here Only those variables that have been defined with an identical name and data type to variables in the parent task and with a Usage of Input Only or Input amp Output will have data passed into them from the parent task when the worklet is launched Only those variables that have been defined with an identical name and data type to v
75. ngeToMidVenue and then once the worklet has completed continue or unsuspend the workitem Following the logic of the ripple down rule if the tickets sold are also less than 50 of the capacity then we want instead to suspend the workitem run the ChangeToSmallVenue worklet and then unsuspend the workitem Finally if there has been less than 20 of the tickets sold we want instead to suspend the entire case run a worklet to cancel the show and then remove i e cancel the case In this example the first rule s condition evaluates to true for a Tickets Sold value of 12600 and a seating capacity of 25000 so the child rule node on the true branch of the parent is tested Since this node s condition evaluates to false for the case data the rule evaluation is complete and the last true node returns its conclusion The result of all this can be seen in the Available Work screen of the worklist The Do Show workitem is marked as Suspended and thus is unable to be selected for checking out while the ChangeToMidVenue worklet has been launched and its first workitem Cancel Stadium is enabled and may be checked out By viewing the log file you will see that the ChangeToMidVenue worklet is being treated by the Exception Service as just another case and so receives notifications from the Engine for pre case and pre item constraint events also Check out Cancel Stadium accept the default values and submit Notice that the worklet h
76. o immediately replace the running worklet case for workitem 12 3 3_Treat using the new rule Workitem Spec ID Casualty_Treatment Workitem Case ID 12 3 Workitem Task ID Treat Running Worklet TreatFever Worklet Case ID 13 Figure 20 Message Dialog Offering to Replace the Running Worklet If the Yes button is clicked then in addition to adding the new rule to the rule set the Rules Editor will contact the Worklet Service and request the change For this process to succeed the following must apply Tomcat is currently running and the Worklet Service is correctly installed Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 29 The Service URI specified in the Rules Editor configuration dialog is valid and The worklet originally chosen is currently running A message dialog will be shown soon after with the results of the replacement process sent from the Worklet Service back to the Rules Editor similar to Figure 21 If the No button is clicked then the new rule is simply added to the rule set Result of replace request Locating workitem 4 3 3_Treat in the set of currently handled workitems Found Cancelling running worklet case with case id 5 for workitem done Launching new replacement worklet case based on revised ruleset done The worklet TreatHighHeartRate has been launched for workitem 4 3 3_Treat and has case id 6 Figure 21 Result of Replace Request Dialog
77. og shows the variables defined for the task each one of these maps to a net level variable so that in this example all of the data collected from a patient in the first two tasks are made available to this task The result is that all of the relevant current case data for this process instance can be used by the Worklet Service to enable a contextual decision to be made Note that it is not necessary to map all available case data to a worklet enabled task only that data required by the Service to make an appropriate decision How this data is used will be discussed later in this manual Update Task Decomposition Treat Task Decomposition Label Treat Task Decomposition Variables Name Type Usage Name string Input Only PatientID string Input Only Age long Input Only Sex string Input Only HeartRate long Input Only SystolicBP long Input Only DiastolicBP long Input Only Height double Input Only Weight double Input Only Fracture boolean Input Only Fever boolean Input Only Rash boolean Input Only AbdominalPain boolean Input Only Wound boolean Input Only Pharmacy string Input Output Treatment string Input Output Notes string Input Output YAWL Registered Service Detail YAWL Service Worklet Dynamic Process Selection Service Default Engine Worklist RPC Style Web Service Invoker SMS Message Module Works if you have
78. oka naaa deduct eae aed caecadeilns a E Eia li C ntents assole predna TE cerry EE Sadana E R a E AET ANNET ANA iii PU BULES gt otete E a E A a a e E E E Aa iii 1 Welcome to the Worklet Service for YAWL eeeseseessssessssrrrsseressssrersssresssrreesseressseresss 1 What is a Custom YAWL Service esssesesssesessssressseressseresssstesssereessstesesseeesseressss 1 What is the YAWL Worklet Service eesseesesseseesseessreisssrresssrresserresssrreessrresseeresss 1 The Selectron Service oriee lie aaa ie saan eA EE aa da oaa O E 1 The Exception Services nisana R n ene E eee 2 Dz Inistallati omnes nia T va e A E RAA Ea C T a R A et 3 Worklet Installation Package eeecesescecesesseeecesseeeeeseeaaeecessaeeesesaeecesenaeeeeseaeeers 3 Installing the Worklet Service cc eesseeeessececeessneeeeseeacecesenaeeecesnaeeeesssaeeeeeeeeeeeeeea 3 1 Extracting and Installing the Repository ee eeescceesseceecesseeceeeseeeeeeenaeeees 3 2 Configure the Service ss scis ig e nnen a iE E a i ver iaa S 4 3 Enabling the Worklet Exception Service seeseeeeseeeersesssserrsesresssrreessreersesees 5 4 Installing the Rules Editor seeeeeseeeeeeeesessesssseessssrsrssrresserresssreessseresserresseee 6 3 Using the Worklet Selection Service eseseseeeseeseesresssrressssressstresssreersssresssrresserresssrees 8 Top level or Parent Specifications sss trr ieten riesi eria rsu rE E E ENEE ATS 8 Worklet Specifications
79. ored Then a pre item constraint notification is received for the next workitem Sell Tickets This workitem records the number of tickets sold and the price of each ticket Enter a price of 100 per ticket and 12600 as the number of tickets sold and then submit the workitem Figure 44 Sell Tickets Ticket Cost 100 He Tickets Sold 12600 Figure 44 The Sell Tickets Workitem detail Notice that the entered number of tickets sold 12600 is slightly more than 50 of the venue s seating capacity 25000 The next workitem Do Show does have a pre item constraint rule tree and so when it becomes enabled the rule tree is queried The effective composite rule for Do Show s pre item tree as viewed in the Rules Editor is Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 47 Effective Composite Rule if TicketsSold lt Seating 0 75 then suspend workitem run worklet ChangeT oMidVenue continue workitem except if TicketsSold lt Seating 0 5 then suspend workitem run worklet ChangeToSmallVenue continue workitem except if TicketsSold lt Seating 0 2 then suspend case run worklet CancelShow remove case Figure 45 Effective Composite Rule for Do Show s Pre Item Constraint Tree In other words when Do Show is enabled and the value of the case data attribute TicketsSold is less than 75 of the seating capacity of the venue we would like to suspend the workitem run the compensatory worklet Cha
80. orklet in the YAWL editor However when adding a conclusion for a rule type other than Selection i e an exception rule type an exception handling sequence needs to be defined that will manage the handling process invoked by the rule The earlier section on the Exception Service detailed the various actions that make up the available set of exception handling primitives or tasks that may be sequenced to form an entire handling process sequence easier by allowing you to create the sequence graphically Simply select the appropriate primitive from the toolbox on the left and then click on the drawing canvas to place the selected primitive Figure 26 shows an example of the Draw Conclusion dialog En The Draw Conclusion dialog makes the process of defining an exception handling Canvas Wee q T q Clear Cancel Figure 26 The Draw Conclusion Dialog Use the Arc Tool to define the sequence order First select the Arc Tool in the toolbox then click and hold on the first node drag the mouse pointer until it is over the next node in the sequence then release the mouse For a conclusion to be valid and thus allowed to be saved there must be a direct unbroken path from the start node to the end node the start and end nodes are always displayed on the Worklet Custom Service Manual Beta 8 Worklet_
81. other things in the conditional expressions of rule nodes other than the process instance s data attributes and values It is envisaged that the class s functions can be extended into areas such as process mining querying resource logs and external data sets Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 60 Appendix B Sample Log generated by Walkthrough C 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 2006 09 NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNDN LH WWWWWWWWWWWWWWWWWNNNNNNNNNNNNNNNNNNNNNNNNNNNN DN NY 216 216 ARE 2 16 iLE 2 16 2 28 2 28 128 2 28 2 28 228 His hore 256 7563 25165 756 5 256 256 35 6 756 256 7563 756 256 256 256 3565 256 so Os 202 8023 0 23 202 202 OZS 10 468 10 484 210 500 210 500 1207 S25 SLOSIS 259 281 259 281 259 281 259 296 759 437 WWWWWODWDWOCO 31 875 31 984 32 093 32 109 32 156 132 281 17 968 18 000 18 015 18 078 18 093 18 093 08 000 08 015 08 140 08 140 08 156 08 171 08 203 08 343
82. pecial variable this The Worklet Service provides a discrete class that enables developers to extend the availability of such defined functions That is a developer may define new functions that can then be used as or as part of composite conditional expressions in rule nodes That class is called RdrConditionFunctions the source code for the class can be found in the au edu qut yawl worklet support package Currently this class contains a small number of examples to give developers an indication of the kinds of things you can do with the class and how to create your own functions The class code is split into four sections S Header Execute Method Function Definitions and S Implementation To successfully add a function these rules must be followed 1 Create the function i e a normal Java method definition and add it to the function definitions section of the code Ensure the function is declared with the access modifier keywords private static and returns a value of String type 2 Add the function s name added to the array of _functionNames in the header section of the code 3 Add a mapping for the function in the execute method using the examples as a guide Once the function is added it can be used in any rule s conditional expression Let s use the max function as a simple example walkthrough to be read in conjunction with the source code for the class The first thing to do is
83. pended workitems for the case effectively continuing case execution Continue All Cases un suspends execution of all previously suspended workitems for all cases of the specification in which the workitem is defined or of which the case is an instance effectively continuing all running cases of the specification Remove Workitem removes or cancels the workitem execution ends and the workitem is marked with a status of cancelled No further execution occurs on the process path that contains the workitem Remove Case removes cancels the case Case execution ends Remove All Cases removes cancels all case instances for the specification in which the workitem is defined or of which the case is an instance Restart Workitem rewinds workitem execution back to start Resets the workitem s data values to those it had when it began execution Force Complete WorkItem completes a live workitem Execution of the workitem ends and the workitem is marked with a status of ForcedComplete which is regarded as a successful completion rather than a cancellation or failure Execution proceeds to the next workitem on the process path Force Fail Workitem fails a live workitem Execution of the workitem ends and the workitem is marked with a status of Failed which is regarded as an unsuccessful completion but not a cancellation execution proceeds to the next workitem on the process path FA
84. posite Rule for Do Show s Pre Item Constraint Tree 48 The Book Ent Centre Workitem detail ccccccccccceseseseeeeseseseseeesseneeeees 48 Workflow Specifications Screen OrganiseConcert case running ee 49 Case Viewer SCreens ys ek saar a ea age E a aa i a Gees 50 Raise Case Level Exception Screen Organise Concert example 4 50 Available Work Items after External Exception Raised eesseeeeeseeeeeeees 51 The Timeout Test 3 Specification eeeeesseeesseesesrresesreersssresrsrresssrrersseresssrress 52 Rules Editor Showing Single Timeout Rule for Receive_Payment Task 53 Rule detail for Receive Reply ccceeeescecessneceeensececesnaceeesesaeeeceseaeeeesenaeeeeees 53 Available Work After CancelOrder Worklet Launched 54 Reject Worklet Selection Screenin rreri ierse iaeiei etea ieii 55 Example of a New Case Level Exception Definition eeeeeeenecreerrrreeereesrre 56 Administration Tasks Screen detail ccccccccceesceessseseeeeeeeeeeseseseeeesesenees 56 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 v 1 Welcome to the Worklet Service for YAWL What is a Custom YAWL Service An important point of extensibility of the YAWL system is its support for interconnecting external applications and services with the workflow execution engine using a service oriented approach This enables running workflow instances and external applications to
85. r the Test Fever workitem is different to the case id of the Test Fever workitem has mapped the patient name and id values and the Go back to the Available Work page and check out the Test Fever workitem The 8 particular symptom fever from the Treat workitem checked out by the Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 40 Worklet Service In addition it has a Notes field where a medical practitioner can enter observations about the patient s condition Figure 34 Enter some information into the Notes field and then submit it YAWL Home Administrate Welcome to YAWL admin Active YAWL Specifications Specification iD Spec Name Documentation XML Cases O TreatFever Treat Fever Worklet to treat a fever View TreatFever w A simple medical treatment process designed to test and demonstrate the Worklet Dynamic Process Selection Service within the YAWL engine Launch Case Reset oO Casualty Treatment Casualty Treatment View Casualty Treatment 2 Figure 33 TreatFever Specification Uploaded and Launched Check out the next workitem Treat Fever and then edit it This workitem has two additional fields Treatment and Pharmacy where details about how to treat the condition can be entered Figure 35 Enter some data here and then submit it Test Fever Patient ID 123456 Notes _ bitten by spider x Fever true O false Name Iva Payne is Figure 34
86. rating System Windows OS s 98SE or better Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 6 The Microsoft NET framework any version If you don t have the framework installed it can be downloaded for free from Microsoft http www microsoft com downloads The Rules Editor tool is found in the rulesEditor folder of the worklet repository It can be executed directly from there no further installation is required E Worklet Rules Editor lt Browse gt Casualty_Treatment la T File Rule Options Help Q Ba Rule Type Selection gt Task Name Treat z RDA Tree Cornerstone Case Rule 0 Sel 2375493 ex ag n as DiastolicBP 95 a Height 1 65 Rule 2 HeartRate 80 Rule 3 SystolicBP 140 Rule 4 Fracture false Rule 5 Rues Name Ben Dover Selected Node Node ID 2 Parent Node ID fi Condition Wound tue Conclusion 1 select TreatWound Description i worklet for a wound Figure 6 The Worklet Rules Editor For more details on the Rules Editor and how to use it refer to Section 5 Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 T7 3 Using the Worklet Selection Service Fundamentally a worklet is nothing more than a workflow specification that has been designed to perform one part of larger or parent specification However it differs from a decomposition or sub net in that it is dynamically assigned to per
87. rough we ll change the values to one five two six and three seven respectively As you edit and submit each Get_Bob workitem notice that the corresponding Verify List workitem is automatically checked in by the Worklet Service you ll only see this if you are logged in as admin Since the Bob worklets contains only one task editing and submitting this workitem also completes the worklet case Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 44 YAWL Home Administrate Welcome to YAWL admin Active YAWL Specifications Specification ID Spec Name Documentation XML Cases O BobThree Bob Three Worklet to enact when bob is three View BobThree 6 O BobTwo Bob Two Worklet to enact when bob is two View BobTwo FA O BobOne Bob One Worklet to enact when bob is one View BobOne 5 IreatFever Treat Fever Worklet to treat a fever View TreatFever List Maker o wListMaker Example 4 process to demonstrate how worklets vidi asiak A S Cworklet handle a multiple task rS enabled A simple medical treatment process Casualty designed to test and demonstrate the i Casualty Treatment wew Casualty Treatment e Casualty Treatment Treatment Worklet Dynamic Process Selection Service View Casualty Treatment within the YAWL engine Launch Case Reset Figure 40 Bob Specifications Loaded and Launched by the Worklet Service After the third workitem has been edited and submitted
88. rtes Das Address http flocalhost 8080 workletService rejectWorklet caselD 32 Eco Links Customize Links 4 Free Hotmail Windows ee ery Worklet Service Reject Worklet Selection Case ID Specification ID 32 CancelOrder Please complete each of the fields below Proposed Title Reason for Rejection a YAW Lis distributed under the LGPL Done 2 Local intranet Figure 55 Reject Worklet Selection Screen To raise an unexpected exception at the case level follow the same process to the Case Viewer screen but click the Raise Exception button On the Raise Case Level Exception screen discussed in Walkthrough D select New External Exception from the list and submit the form You will be redirected to the Define New Case Level Exception screen Enter a proposed title a description of the scenario what has happened to cause the exception and a optionally a proposal or description of how the new worklet will handle the exception in plain text and then submit the form See Figure 56 for an example using the Organise Concert specification Raising an item level exception is identical except that the Raise Exception button is clicked on the Available Work screen rather than the Case Viewer screen The information entered on the form is sent to a Worklet Service Administrator who will action the rejection or new exception by adding a new rule to the rule set and optionally
89. s are vastly different to others In a typical workflow process this is the part of the process where things could get very complicated particularly if we tried to build every possible treatment as a conditional branch into the process model The Worklet Service greatly simplifies this problem by providing an extensible repertoire of discrete workflow processes worklets which in this example each handle the treatment of a particular medical problem By examining the case data collected in the earlier tasks the Worklet Service can launch as a separate case the particular treatment process for each case Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 39 This method allows for a simple expression of the task in the parent process i e a single atomic Treat task signifies the treatment of a patient whatever the eventual treatment process may be as well as the ability to add to the repertoire of worklets at any time as new treatments become available without having to modify the original process When the Triage workitem is submitted the next task in the process Treat becomes enabled Because it is worklet enabled the Worklet Selection Service is notified The Selection Service checks to see if there is a set of rules associated with this workitem and if so the service checks out the workitem When this occurs the YAWL Engine marks the workitem as executing externally to the Engine and waits for the workitem to b
90. s stage a Process Description Find out what s needed get a couple of quotes hire the la equipment get it delivered to the venue YAWLis distributed under the LGPL 2 Local intranet Figure 56 Example of a New Case Level Exception Definition If you are logged into the YAWL worklist as an admin user and the exception service is enabled you will notice an extra link on the top menu of most of the worklist screens called Worklet Admin Tasks for example Figure 56 above This link allows administrators to view the current list of outstanding worklet rejections and requests for new exception handlers It also allows administrators to view the details of each outstanding rejection and exception request and to mark it as completed removing them from the list after it has been actioned figure 57 Worklet Service Administration Tasks Title Case ID Task Type Try Another Reminder 32 Rejected Worklet Selection Completed Figure 57 Administration Tasks Screen detail Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 56 Appendix A Defining New Functions for Rule Node Conditions In Section 5 we saw how rule conditions could be defined using a combination of arithmetic operators and operands consisting of data attributes and values found in workitems and at the case level of process instances In Walkthrough D an example of a defined function was given isNotCompleted using the s
91. se As soon as the Engine launches the case it notifies the Exception Service via a PreCaseConstraint event If the rule set for OrganiseConcert contains a rule tree for pre case constraints that tree will be queried using the initial case data to determine whether there are any pre constraints not met by the case In this example there are no pre case constraint rules defined so the notification is simply ignored Tip To follow what is happening watch the log output in the Tomcat command window both the exception and selection services log all interactions between themselves and the Engine to the Tomcat window and to a log file found in the logs folder of your Tomcat installation See Appendix B of this manual for a sample log output for this walkthrough Pre case constraints can be used amongst other things to ensure case data is valid or within certain ranges before the case proceeds can be used to run compensatory worklets to correct any invalid data or may even be used to cancel the case as soon as it starts in certain circumstances As a trivial example of the last point launch an instance of the Casualty Treatment specification discussed in Walkthrough A and enter smith for the patient name when the case starts The Casualty Treatment rule set contains a pre case constraint rule to cancel the case if the patient s name is smith presumably smith is a hypochondriac This is also an example of exception rules a
92. source reports that it is unavailable to accept the allocation This event is not currently supported by the Exception Service ConstraintViolation This event occurs when a data constraint has been violated for a workitem during execution as opposed to pre or post execution This event is not currently supported by the Exception Service Exception Handling Primitives For any exception event that occurs a handling process may be invoked Each handling process contains a number of steps or primitives in sequence and is defined graphically using the Worklet Rules Editor see Section 5 Each of the handling primitives is introduced below Suspend WorkItem suspends or pauses execution of a workitem until it is continued restarted cancelled failed or completed or its parent case is cancelled or completed Suspend Case suspends all live workitems in the current case instance a live workitem has a status of fired enabled or executing effectively suspending execution of the case Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 15 Suspend All Cases suspends all live workitems in all of the currently executing instances of the specification in which the workitem is defined effectively suspending all running cases of the specification Continue Workitem un suspends or continues execution of the previously suspended workitem Continue Case un suspends execution of all previously sus
93. stone data and a description click the Add Rule button to add the rule to the tree The new node will be displayed at the selected position on the tree with the relevant coloured node icon indicating whether it is a true or false node of its parent New potential node add points will also be displayed See Figure 25 for an example of a newly created tree that has several nodes added RDA Tree Rule 0 9 Rule 1 Rule 2 0 New True Rule I Rues Oo New True Rule f Rule 4 f Rues 0 New True Rule 0 New False Rule O New False Rule 0 New False Rule Figure 25 Creating a New Rule Tree Repeat the add rule procedure for however many rule nodes you wish to add by clicking on the appropriate yellow node note that when you click on a node other than yellow its stored details are displayed in the various form inputs Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 33 TIPS S If the number of nodes starts to get a little confusing you can check which node is the parent of the selected node by looking at its id in the Selected Node panel S If you start to add details for a new node then change your mind about adding it simply click on any other node rather than clicking on the Add Rule button doing that will immediately discard any input data values Don t click Cancel that closes the entire form without saving anything see below When you are done adding nodes click the Add Tree b
94. t Types Constraints are rules which are applied to a workitem or case immediately before or after execution of that workitem or case begins Thus there are four types of constraint exception S CasePreConstraint case level pre constraint rules are checked when each case i e instance begins execution S ItemPreConstraint item level pre constraint rules are checked when each workitem in a case becomes enabled i e ready to be checked out S ItemPostConstraint item level post constraint rules are checked when each workitem moves to a completed status and S CasePostConstraint case level post constraint rules are checked when a case completes The Exception Service receives notification from the YAWL Engine when each of these events occur then checks the rule set for the case to determine firstly if there are any rules of that type defined for the case and if so if any of the rules evaluate to true using the contextual data of the case or workitem If the rule set finds a matching rule for the exception type and data an exception process is invoked Note that for each of the constraint events an exception process is invoked for a rule when that rule s condition evaluates to true So for example if the condition of an ItemPreConstraint rule for a Triage task was PrivateInsurance false and that value of that attribute in the workitem was also false then the exception process for that rule would be invoked E
95. tion External Trigger Example It has been stated that every case instance involves some deviation from the standard process model Sometimes events occur completely removed from the actual process model itself but affect the way the process instance proceeds Typically these kinds of events are handled off system so there is no record of them or the way they were handled kept for future executions of the process specification The Worklet Exception Service allows for such events to be handled on system by providing a means for exceptions to be raised by users externally to the process itself The Organise Concert specification will again be used to illustrate how external triggers work Go to the Administrate Screen and launch another instance of the Organise Concert specification Execute and submit the first workitem To raise a case level external exception go to the Workflow Specifications screen and click on the current case id for the Organise Concert case Figure 47 Active YAWL Specifications Specification ID Spec Name Documentation XML Cases TreatFever Treat Fever Worklet to treat a fever View TreatFever ChangeToMidVenue ChangeToMidVenue Saad ftleketsales lessithan View ChangeToMidVenue 4 simple medical treatment process des Casualty Treatment Casualty Treatment _ View Casualty Treatment Example used to test workletService Exception Handling O OrganiseConcert Organise Concert View Organise
96. tion input in the New Rule Node panel Thus a condition for the new rule has been easily created based on the differing data attribute and value that has caused the original worklet selection to be invalid for this case Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 26 Note that it is not necessary to define the rule as Rash True amp HeartRate 190 as might first be expected since this new rule will be added to the true branch of the TreatRash node By doing so it will only be evaluated if the condition of its parent Rash True first evaluates to True Therefore any rule nodes added to the true branch of a parent become exception rules of the parent In other words this particular tree traversal can be interpreted as if Rash is True then return TreatRash except if HeartRate is also 190 then return where whatever worklet we decide to return for this rule see more below Now the new rule is fine if in future cases a patient s heart rate will be exactly 190 but what if it is 191 or 189 or 250 Clearly the rule needs to be amended to capture all cases where the heart rate exceeds a certain limit say 175 While selecting data items from the Current Case panel is fast and easy it is often the case that the condition needs to be further modified to correctly define the relevant rule The Condition input allows direct editing of the condition Conditions are expressed as strings of oper
97. tory refer Figure 18 An appropriate worklet for this rule may be chosen from the list or if none of the existing worklets are suitable a new worklet specification may be created ee Choose Worklet ka worklet Casualty Treatment Casualty Treatment v1 ChangeT oLargerVvenue ChangeT oMidVenue ChangeT oSmallVenue MultiT est OrganiseConcert mw New Cancel x _ Figure 18 The Choose Worklet dialog Clicking the New button on this dialog will open the YAWL Editor so that a new worklet specification can be created When defining the new worklet bear in mind that to pass data from the original work item to the worklet the names and data types of the variables to be passed must match those of the work item and be created as net level variables in the worklet specification Also all new worklets must be saved to the worklets folder of the repository so that the Worklet Service can access it TIP You may choose more than one worklet in this dialog simultaneously by holding down the Ctrl or Alt keys while clicking the mouse in the usual Windows way If you choose several worklets when this rule is invoked for a process at runtime all of the worklets chosen will be launched concurrently and the process will continue only after all the worklets launched have completed When the new worklet is saved and the YAWL Editor is closed the name of the newly created worklet will be displayed and selected in t
98. untime A brief introduction to each Service follows The Selection Service The Worklet Dynamic Process Selection Service or Selection Service enables flexibility by providing a process designer with the ability to substitute a workitem in a YAWL process at runtime with a dynamically selected worklet a discrete YAWL process that acts as a sub net for the workitem and so handles one specific task in a larger composite process activity The worklet is dynamically selected and invoked and may be created at any time unlike a static sub process that must be defined at the same time as and remains a static part of the main process model Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 1 An extensible repertoire or catalogue of worklets is maintained by the Service Each time the Service is invoked for a workitem a choice is made from the repertoire based on the contextual data values within the workitem using an extensible set of rules to determine the most appropriate substitution The workitem is checked out of the YAWL engine and then the selected worklet is launched as a separate case The data inputs of the original workitem are mapped to the inputs of the worklet When the worklet has completed its output data is mapped back to the original workitem which is then checked back into the engine allowing the original process to continue Worklets can be substituted for atomic tasks and multiple instance atomic tasks In
99. utton to add the tree you have just created to the tree set selected via the selected Rule Type and Task Name lists IMPORTANT Once you have added the newly created tree to the selected tree set using the Add Tree button you will no longer be able to add nodes to the tree via the New Rule Set form This is to protect the integrity of the rule set Since each subsequent rule will be added because of an exceptional case or where the selected worklet does not fit the context of a case the preferred method is to create the base rule set and then add rules as they become necessary via the Add Rule form as described earlier In this way added rules are based on real case data and so are guaranteed to be valid In a similar vein there is no option to modify or delete a rule node within a tree once the tree has been added to the rule set since to allow it would destroy the integrity of the rule set because the validity of child rule nodes depend on the conditions of their parents When a tree is added to the tree set S If itis a case level tree the rule type that the tree represents will be removed from the Rule Type list That is the rule type now has a tree defined for it and so is no longer available for selection on the New Rule form S If itis an item level tree the task name that the tree represents will be removed from the Task Name list That is the task now has a rule tree defined for it for the selected rule type and so is no lon
100. way they are handled is rarely recorded or in some instances the entire process must be aborted Alternately an attempt might be made to include every possible twist and turn into the process model so that when such events occur there is a branch in the process to take care of it This approach may lead to very complex models where much of the original business logic is obscured and doesn t avoid the same problems when the next unexpected exception occurs The Exception Service addresses these problems by allowing you to define worklets that will act as exception handling processes for parent workflow instances when certain events occur Rules are defined in much the same way as for the Selection Service but with added features that enable you to pause resume cancel or restart the task case or all cases of a specification that triggered the exception Because the service allows you to define exception handlers for all exception events and even to add new handlers at runtime all exception events are able to be captured on system so that the handlers are available to all future occurrences of a particular event for the same context And since the handlers are worklets the original parent process model only needs to contain the actual business logic for the process while the repertoire of handlers grows as new exceptions arise or different ways of handling exceptions are formulated IMPORTANT While the Selection Service is lin
101. workitem instances of the task are created one for each of the Bob values entered previously The Worklet Service will determine that it is a multiple instance atomic task and will treat each child workitem instance separately and will launch the appropriate worklet for each based on the data contained in each Since the data in each child instance is different in this example the Worklet Service starts 3 different worklets called BobOne BobTwo and BobThree Each of these worklets contains only one task Go to the Available Work page There are three workitems listed each one the first workitem of a separate case see Figure 39 Workflow YAWL Home Administrate Available Work Checked Out Wor Logout Specifications Welcome to YAWL admin Available Work Items iD Task Description Status Enablement Time O 5 2 Get Bob One Get_Bob_One Enabled Dec 18 12 36 57 7 2 Get Bob Two Get_Bob_Two Enabled Dec 18 12 36 59 O 6 2 Get Bob Three Get_Bob_Three Enabled Dec 18 12 36 58 Check Out Reset Figure 39 Workitems from each of the 3 Launched Worklet Cases Go to the Workflow Specifications page to see that the BobOne BobTwo and BobThree specifications have been uploaded and launched by the Worklet Service as separate cases Figure 40 note the case numbers Go back to the Available Work page and check out all three workitems Edit each of the Get_Bob workitems and modify the values as you wish for this walkth
102. xternally Triggered Types Externally triggered exceptions occur not through the case s data values but because something has happened outside of the process execution that has an affect on the continuing execution of the process Thus these events are triggered by a user depending on the actual event a particular handler will be invoked There are two types of external exceptions CaseExternalTrigger for case level Worklet Custom Service Manual Beta 8 Worklet_ Man 1 0 14 events and ItemExternalTrigger for item level events See later in this section for examples of each and how they are invoked TimeOut A timeout event occurs when a workitem is linked to the YAWL Time Service and the deadline set for that workitem is reached In this case the YAWL Engine notifies the Exception Service of the timeout event and passes to the service a reference to itself and each of the other workitems that were running in parallel with the timed out item Therefore timeout rules may be defined for each of the workitems affected by the timeout including the actual timeout workitem itself ItemAbort An ItemAbort event occurs when a workitem being handled by an external program as opposed to a human user reports that the program has aborted before completion This event is not supported by this version of Exception Service ResourceUnavailable This event occurs when an attempt has been made to allocate a workitem to a resource and the re

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