Worklet Selector Custom YAWL Service User Manual
Contents
1. Workitem Spec ID Casualty Treatment Workitem Task ID Treat Workitem Case ID 4 3 Running Worklet TreatRash Worklek Case ID 5 Figure 12 Message Dialog Offering to Replace the Running Worklet If the Yes button 1s 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 The Service URI specified in the Rules Editor configuration dialog is valid and Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 16 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 to the Rules Editor similar to Figure 13 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 43 3 Treat and has case id 6 Figure 13 Result of Replace Request Dialog Figure 14 shows the main Rules Editor screen with the new rule added in the correct place in the tree wit2. The YAWL Project For more information and progress on the YAWL project visit the YAWL Homepage www yawl system com YAWL Architecture The following image depicts the interaction between components of the YAWL Engine Apache Tomcat Web Service yawlWSInvoker war y o 246 ee gt 2 Browser http localhost 3080 worklist Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 2 Creating Worklet Enabled Specifications Fundamentally a worklet is simply 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 perform a particular task at runtime while sub nets are statically assigned at design time So rather than being forced to define all possible branches in a specification 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 The first thing you need to do to make use of the service is to create a number of YAWL specifications one which acts 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 an
3. false Pash O true false Wound O true false Name Iva Payne x Abdominal Pain true false Fracture Otrue E false Figure 20 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 with the worklet 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 methods 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 a 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 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 trea
4. Work page and check out all three workitems di Go to the Checked Out Work page If you are logged in as admin you ll see something like Figure 30 Edit each of the Get_Bob workitems and modify the values as you wish for this walkthrough 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 1f 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 User Manual Beta 7 Worklet_User_Man_v0 7 doc 27 T Woarkflo TAWL Home Aadministrate li Available Work Checked Cut Work Logout Specifications Welcome to YAWL admin Checked Out Work Items if Task Descrotlon Enablement Tine Start Tine 42 3 Werfy_list Verity_list Dec 18 12 36 54 Dec 18 12 36 56 7 1 2 Get Bob Two Get Bob Two Dec 15 12 36 59 Dec 18 12 45 15 4 4 3 Verify_list Verity_list Dec 18 12 36 54 Dee ts 1236156 5 1 2_Get_Bob One Get _Bob One Dee 18 12 36 57 Qec 18 12 45 14 4 3 3 Verity_list Verity_list Dec 18 12 36 54 Dec 18 12 36 56 6 1 2 Get Bob Three Get_Bob_Three Dec 18 12 36 58 Dec 18 12 45 16 Edit Work Item Add New Instance suspend Task Figure 30 The User and Worklet Service Checked Out Items After the third workite
5. for the case that was the catalyst for the rule addition must be located and loaded into the Rules Editor From the Add New Rule screen click the Open button to load the selection information from file The File Open dialog that displays should open in the selected folder of the repository Select the appropriate file for the case in question then click OK For example selecting 4 3 3_Treat TreatRash xws means that case instance 4 3 had selected for the Treat task the worklet TreatRash Note that the file chosen must be a selection 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 arule set that has no relation to the xws file opened here If the specifications don t match an error will display Figure 10 shows the Add New Rule screen with the file 4 3 3_Treat TreatRash 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 The New Rule Node panel is where the details of the new rule are 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 t
6. UIEmMen Sa 2 TS YAW WY les OC Ohop idad 3 YAWLEAr Nte UTS o betta iain atesaieeantaaeubennnbetee 3 2 Creating Worklet Enabled SpecifiCati0DS ooooccccccccnnnnonncnnnnnnncnnonancnnnnnnnnnnnnnnos 4 Top levelor Parent SpeciliCatiOns us pais lid dedito ida 4 WY OFEKICE SPECILICAUIONS nascia a 6 3 TNE Work let Rules Edi it 9 Worker RUE Sa 9 O ION 10 Browsing an Existing Rule Seu aaa 11 Addins a New Rear iailc s 13 Dynamic Replacement of an Executing Worklet ccccoooooooocccccnncnos 16 Ceann a New Rule Solasean a 18 4 Walkthrough Using the Worklet Service cccoooooonocnccncnnnonononnncnnnnnnnnnnnnos 20 A Worklet Enabled Atomic Task Example ooccccccccnncnoocccnnnnnnonnnncnnnnnnnnnos 20 B Worklet Enabled Multiple Instance Atomic Task Example 29 Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 111 1 Welcome to the YAWL Worklet Service 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 interact with each other in order to delegate work or to signal the creation of workitems or a change of status of existing workitems Custom YAWL services interact with the YAWL engine through XML HTTP messages via certain endpoint
7. Worklet Selector Custom YAWL Service User Manual Beta 7 Release QUT Faculty of A information Technology Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc Document Control 18 Dec 2005 Michael Adams Initial Draft Preface This manual contains instructions for using the Worklet Dynamic Process Selection 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 7 release This icon indicates a hands on method or instruction Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 11 Contents PCT AC A E o A A E AAT A E A N 11 1 Welcome to the YAWL Worklet Service oooccccccccoononoccconnnononononoccnnnnnnnnnnnnos l What is a Custom YA WL SOIVICE lin is l Whatis the YAW Wo rklet Servi lia l Obtaining the Latest Version of the Worklet Service oocccccoononoccccnnnnnnnss 2 Software REQ
8. a 7 Worklet_User_Man_v0 7 doc 6 TreatFever Test Fever Treat Fever Figure 4 The TreatFever worklet process 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 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 need to be defined as net level variables in the worklet specification Figure 5 shows the net level variables for the TreatFever task Update Net Decomposition Treatrever Het Decomposition Label Tre atF ewen Het Decomposition Variables Mame Type Usage Fever boolean Input Only Input Output PatientID Figure 5 Net level variables for the TreatFever specification Note the following Only a sub set of the variables defined in the parent Treat task are defined here see Figure 2 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 workle
9. d editing YAWL specifications and the definition of data variables and parameters for tasks and specifications 1s 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 the Worklet Service Installation Manual 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 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 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 an individual task and any number of tasks in a particular specification can be associated
10. d operators and sub expressions may be parenthesised The following operators are supported Arithmetic Comparison Logical AND Logical OR Logical NOT All conditions must finally evaluate to a Boolean value To make the condition for the new rule more appropriate the condition YE HeartRate 190 should be edited to 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 Worklet field of the New Rule Node panel refer Figure 10 This input is a drop down list that contains the name of all the worklets in the worklets folder of the worklet repository An appropriate worklet for this rule may be chosen from the list or 1f none are suitable a new worklet specification can be created Clicking the New button next to the worklets list will open the YAWL Editor so YE that a new 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 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 When the new worklet is saved and the Y AWL Editor is closed the name of the newly created worklet will be displayed and selected in
11. d 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 17 3 The Worklet Dynamic Process Selection Service for YAWL Microsoft Internet Explorer File Edit View Favorites Tools Help ay pack O AAA Aseh Favorites 2 O Ly Links E vawL Diary El Java API 4 JFileChooser Java 2 Platform SE v1 4 0 Mars Address El http localhost 8080 workletSelector ib v Go O The Power of Expressiveness Welcome to the Worklet Dynamic Process Selection Service for YAWL ow This service provides the abilty 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 4 repertoire or catalog of worklets is maintained 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 allow
12. e service ON AD 10 The Power of Expressiveness ae workfl YTAWL Home Administrate es Available Work Checked Out Work Logout Specifications 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 21 New Case Launched by the Worklet Service Note that the case id for the Test Fever workitem is different to the case id of the parent process 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 22 D Go back to the Available Work page check out the Test Fever workitem and then YE edit it in the Checked Out Work page Note that if you are logged in as admin you Il also see the checked out Treat workitem on this page this workitem should not be edited as it has been checked out by the worklet service Any workitems checked out by external services will only appear here if you are logged in as admin The Test Fever workitem has mapped the patient name and id values and the particular symptom fever from the Treat workitem checked out by the worklet service In addition it has a Notes field where a medical practitioner can enter Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 23 observations about the patient s condition Figure 23 Enter some informa
13. e Rules Editor Configuration Dialog Some checks will be made 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 the rule set for each worklet enabled task in a particular specification to add new rules to the current rule set and to create a new rule set for a new specification Browsing an Existing Rule Set To load a rule set into the Rules Editor click on the File menu then select YE Open The File Open Dialog should open with the rules folder of the repository selected Select the file you wish to open and then click OK Figure 9 shows the main screen with the rule set for the Casualty Treatment specification loaded On this screen you may browse through each node of the rule set tree and view the various parts of each node Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 11 Worklet Rules Editor Casualty Treatment Fie Rule Options Help Task Treat AOR Tree Cornerstone Case PatientID 3457687 Ses M DiastolicBP 80 Height 1 8 Hearthate 2 SustolicbP 120 Fracture false Fever tue Fash false Wound false Name Buster Legg Selected Node Node ID Parent Node ID E Condition Fever tue worklet TreatFever Description basic worklet for a fewer Figure 9 Rules Editor Main Screen The screen s title bar s
14. ed from the root node along the branches each node having its condition evaluated If a Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 9 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 1s evaluated When a terminal node is reached 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 Of course to maintain a rule set of any complexity by directly editing the XML formatted file would be daunting to say the least To make things much easier a Rules Editor tool is available and can be found in the rulesEditor folder of the worklet repository It can be run directly from there no further installation 1s required depending on the requirements below The Rules Editor The 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
15. ent process Discharge to execute Go to the Available Work page and you ll see that the Discharge workitem is YE avallable Figure 25 Edit 1t 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 1123456 E Notes bitten by spider i Pharmacy aspirin twice a day Name va Payne a Treatment jant yenene K Submit Figure 25 Discharge Workitem with Data Mapped from TreatFever Worklet B Worklet Enabled Multiple Instance Atomic Task Example This walkthrough takes the List Maker example from the YAWL Editor User Manual pp 46 47 and worklet enables the Verify List task to show how multiple instance atomic tasks are handled by the worklet service 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 26 shows the specification Quist maken 72 1 done Verfylist Show list Create list items Figure 26 The wListMaker specification Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 25 Go to the Administrate page and upload the wListMaker specification from the YE 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 Figu
16. for the Casualty_Treatment xml Y AWL process specification Figure 6 shows an excerpt from that file atl Version TiO Pracodiig Uert a gt spec gt lt Lask name Treat gt lt ruleNode gt lt id gt O lt id gt lt parent gt 1 lt parent gt e lt trueChild gt 1 lt trueChild gt lt falseChild gt 1 lt falseCchild gt lt condition gt True lt condition gt lt conce lusion gt null lt conclusion gt lt cornerstone gt lt cornerstone gt lt description root level default node lt s description gt lt ruleNode gt lt ruleNode gt lt id gt i lt id gt lt parent gt O lt parent gt lt trueChild gt 1 lt truechild gt lt falseChild gt 2 lt falsechild gt lt condition gt Fever true lt condition gt lt conce lusion gt TreatFever lt conclusion lt cornerstone gt Figure 6 Excerpt of rule set file Casualty_Treatment xrs Notice that the file specifies a set of ruleNodes 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 1s 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 A worklet rule set is a set of modified Ripple Down Rules RDR which maintains a rule hierarchy in a binary tree structure The tree is travers
17. h the current case data becoming the Cornerstone Case for the new rule Worklet Rules Editor Casualty_Treatment File Rule Options Help Task Treat ROA Tree Cornerstone Case PatientID 374 99 Sex bl DiastolicBP 80 Height 1 8 HeartRate 190 Systolic BF 120 Fracture false Rash true Wound false Name Patty Ticker Selected Node Mode ID 5 Parent Node ID 5 Condition HeartRate gt 175 Worklet TreatHighHeartRate Description m worklet will be used to treat a very fast heart rate Figure 14 Main Screen after Addition of New Rule Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 17 Creating a New Rule Set When a new specification has been created that contains a worklet enabled task or a task in an existing specification 1s modified to become worklet enabled a new rule set needs to also be created to accommodate the task To create a new rule set click the File menu then select New If there is a rule YE set currently opened 1t must first be closed by clicking File then Close before a new rule set can be created Figure 15 shows the Create New Rule Set screen Worklet Rules Editor Create New Rule Set Process Identifiers Cornerstone Case Data Specification Hame Task Mame Add Cornerstone Data Data Label Data Value Add gt Mew Rule 1 Node Node ID 1 Parent Node ID 0 Condition We orkler BobFive sd New De
18. he case number Check out the Admit workitem then go to the Checked Out Work page select the workitem and click the Edit Work Item button 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 addition to the patient name and id specified earlier there are a number of fields containing some medical data about the patient Each field has some default data to save time but you may edit any fields as you wish Figure 19 When done click the Submit button Admit Weight Diastolic BP SER Patient ID 123456 Height 5 Heart Rate 72 Systolic BP 120 Name Iva Payne Age Figure 19 Editing the Admit Workitem detail Go back to the Available Work page and check out the next workitem Triage YE Then go to the Checked Out Work page and edit the workitem Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 21 The 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 problem One field should be set to True the others to False Let s assume the patient has a fever Set the Fever field to True the rest to False YE and then submit it Figure 20 Triage Patient ID 123456 As Fever true
19. hile the correct choice based on the current rule set is an inappropriate choice for a particular 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 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 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 to open the initially blank Add New Rule screen Every time the worklet service selects a worklet to execute as a substitute for a specification instance s workitem a file 1s created that contains certain descriptive data about the 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 are named according to the following format Caseid Taskid workletname xws For example 4 3 3_Treat TreatRash xws xws for Xml Worklet Selection The case 1d and task 1d refer to the substituted work item not the worklet case instance Thus to add a new rule after an inappropriate selection the particular file
20. hows the name of the specification associated with the currently loaded rule set Under the menu bar the Task drop down list contains the name of each worklet enabled task in the specification If there is more than one task in the list selecting a task name will show the rule set for that task The RDR Tree panel on the top left shows all of the rule nodes in this set in their binary tree structure To make things a little clearer those nodes on the True branch of a parent have a green icon those on the False branch of a parent node have a red icon By clicking on individual nodes the details of the node are displayed to the right and below the tree panel The Selected Node panel on the screen bottom shows the details of the selected node At runtime 1f the condition evaluates to true and there are no more child nodes on the true branch of this node then the worklet named will be returned as the result of this tree traversal The Cornerstone Case panel on the top right shows 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 9 the Cornerstone Case data shows that the variable Fever had a value of true while the variables Rash Wound and Fracture have value of false Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 12 Adding a New Rule There are occasions when the worklet returned for a particular case w
21. ing 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 Please read the user manual for more information YAWL is distributed under the YAWL licence l Done a Local intranet Figure 17 Welcome Page for the Worklet Service A 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 called Treat that is worklet enabled We ll run the example specification to see how worklets operate Navigate to the YAWL Administrate page and upload the Casualty Treatment YE 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 18 Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 20 Casualty Treatment Patient 10113456 sk Figure 18 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 t
22. ion that contains the task Any number of worklets can be created for a particular task For the Casualty Treatment example there are five worklets in the repertoire for the Treat task one for each of the five 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 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 1s described in the next section Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 8 3 The Worklet Rules Editor Worklet Rule Sets A specification may contain a number of tasks one or more of which may be associated with the worklet service For each specification that contains a worklet enabled task the worklet service maintains a corresponding set of rules that determine which worklet will be selected as a substitute for the task at runtime based on the current case data of that particular instance Each worklet enabled task in a specification has its own discrete rule set The rule set or sets for each specification are stored as XML data in a disk file that has the same name as the specification with an xrs extension XML Rule Set All rule set files are stored in the rules folder of the worklet repository For example the file Casualty_Treatment xrs contains the worklet rule set
23. istrate sae Available Work Checked Out Work Logout Specifications Welcome to YAWL admin Avallable Work Items iD Task Description Status enablement Time S 2 Get Bob One Get_Bob_One Enabled Dec 18 12 36 57 fie Get Bob Two Get_Bob_Two Enabled Dec 18 12 36 59 6 2 Get Bob Three Get_Bob_Three Enabled Dec 18 12 36 58 Figure 28 Workitems from each of the Three Launched Worklet Cases Go to the Workflow Specifications page to see that the BobOne BobTwo and YE BobThree specifications have been uploaded and launched by the worklet service as separate cases Figure 29 note the case numbers YAWL Home Administrate IEEE Available Work Checked Out Work Welcome to YAWL admin Active YAWL Specifications Specification ID BobThree Bob Three Worklet to enact when bob is three View BobThree BobTwo Bob Two Worklet to enact when bob is two View BobTwo BobOne Bob One Worklet to enact when bob is one View BobOne TreatFever Treat Fever Worklet to treat a fever View TreatFever List Maker Example A process to demonstrate how worklets worklet handle a multiple task enabled wListMaker View wListMaker 4 simple medical treatment process Casualty designed to test and demonstrate the Casualty Treatment DRAT ma ign Saran aire AE View Casualty Treatment Treatment Worklet Dynamic Process Selection Service within the YAWL engine Figure 29 Bob Specifications Loaded and Launched by the Worklet Service Go back to the Available
24. le Screen Clicking on the line HeartRate 190 in the Current Case panel copies that line YE to the Condition input in the New Rule Node panel Thus the condition for the new rule has been easily created 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 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 972 097 whatever worklet we decide to return for this rule see more below Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 14 Now the new rule is fine if in future cases a patient s heart rate is exactly 190 but what if itis 191 or 189 or 250 Clearly the rule needs to be amended to capture all cases where the heart rate exceeds a certain value 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 capture relevant cases The Condition input allows direct editing of the condition Conditions are expressed a strings of operands an
25. localhost8080Awar Service Documentation Worklet Dynamic Proce Add YAW IL Service Remove YAL Service Figure 3 Registering the worklet service with the YAWL Engine 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 1s executed the YAWL Engine will notify the worklet service when the worklet enabled Treat task becomes enabled The worklet service will then examine the data in the task and use 1t 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 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 Y AWL 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 4 shows a simple example worklet to be substituted for the Treat top level task when a patient complains of a fever Worklet Custom Service User Manual Bet
26. m has been edited and submitted 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 YE the Get_Bob worklets have been mapped back to the original case Figure 31 Show List User List Bob Insert after selected Delete selected esblwo sk H O esblone fe H Figure 31 The Show List Workitem Showing the Changes to the Data Values Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 28
27. 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 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 Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 1 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 Obtaining the Latest Version of the Worklet Service As new versions of the Worklet Service are released to the public they will be available for download at the YAWL website www yawl system com Developers interested in obtaining the source code for the Worklet Service and Rules Editor can download the files from here http sourceforge net projects yawl Software Requirements The Worklet Service requires the YAWL Engine Beta 7 version or higher All other software requirements are as per the requirements of the YAWL Engine Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc
28. re 27 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 swe o h O somo Si cobltved H Figure 27 Start of wListMaker Case with Three Bob Values Entered detail Check out and edit the Create List Items workitem Since the values have already YE 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 service Since this task is a multiple instance atomic task three child instances of the task are created one for each of the Bob values entered previously The worklet service will determine that 1t is a multiple instance atomic task and will treat each child workitem instance separately and 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 YE first workitem of a separate case see Figure 28 Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 26 E workfl TAWL Home Admin
29. rocess Selection Service e Default Engine Worklist RPC Stie Web Service Invoker SMS Message Module Works if you have an account Time service allows tasks to be a timeout task Worklet Dynamic Process Selection Service Figure 2 Associating a task with the worklet service Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 5 The list of task variables in Figure 2 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 Note also that 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 Note also that the description shown of the worklet service will be the description entered into the YAWL Engine when the service was registered Figure 3 see the worklet installation manual for more details and so may differ from that shown in Figure 2 Register New YAWL Service YAWL Service URI httpy
30. rue child or false child node Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 13 Since we have the case data for the original rule and the 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 10 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 Add New Rule 4 3 3_Treat TreatKash Comerstone Case Current Case PatientID 2009810 PatientID 374 99 Sex M DiastolicbP 80 Save Height 1 8 Hearth ate 190 SystolicBP 110 4 SpstolicBP 120 Fracture false 7 Fracture false Age 43 Weight 7 Fever false Fever false Rash true S Rash true Wound false Wound false Mame Theresa Green Name Patty Ticker Cancel New Rule Node Mode ID 6 Parent Node ID 5 Condition Whorklet BobFive kd Hew Description Figure 10 Add New Ru
31. s 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 1s 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 Service for YAWL 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 workitem and so handles one specific task in a larger composite process activity An extensible repertoire or catalogue of worklets is maintained Each time the service is invoked for a workitem a choice is made from the repertoire based on the data within the workitem using a 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
32. scriptions Cancel Figure 15 The Create New Rule Set Screen On this screen The Process Identifiers panel is where the names of the specification and worklet enabled task are defined These names must exactly match the name of the specification that contains the task this rule set is being created for and the name of the task itself In the Add Cornerstone Data panel a set of cornerstone data for the new first rule can be specified Add a variable name to the Data Label input and give it a value in the Data Value input then click the Add button to add it to the set of Cornerstone Case data The New Rule Node 1 panel is virtually identical to the panel on the Add New Rule screen Here a condition and optional description can be entered and the worklet for the new rule created or selected from the list Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 18 It is only possible to add one new rule to a newly created rule set using the Rules Editor in addition to the automatically created root node This is to protect the integrity of the rule set Since each subsequent rule is 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 a rule set with one rule and then add rules as they become necessary via the Add New Rule process described earlier In this way added rules are based on real case data and so are guaranteed to be
33. t may also be defined here Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 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 variables 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 5 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 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 an instance of the same worklet specificat
34. the worklet drop down list Figure 11 shows the New Rule Node panel after the definition of the example new rule has been completed The Description field is optional but recommended Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 15 New Rule Node Mode ID 6 Parent Node ID 5 Condition HeartFate gt 175 Worklet TreatHighH earth ate hal New Description i worklet will be used to treat a very fast heart ratel Figure 11 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 12 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 Do vou wish bo immediately replace the running worklet case for workitem 4 3 3 Treat using the new rule
35. tion into the Notes field and then submit it Administrate Welcome to YAWL admin Active YAWL Specifications Specification id Spec Name Documentation TreatFever Treat Fever Worklet to treat a fever View TreatFever A simple medical treatment process O Casualty Treatment Casualty Treatment designed to test and demonstrate the View Casualty Treatment Worklet Dynamic Process Selection Service within the YAWL engine Figure 22 TreatFever Specification Uploaded and Launched Check out the next workitem Treat Fever and then edit 1t This workitem has two YE additional fields Treatment and Pharmacy where details about how to treat the condition can be entered Figure 24 Enter some data here and then submit it Test Fever Patient 101123456 Sa Notes bitten by spider E Fever true false Name va Payne Figure 23 Test Fever Workitem detail ae Treat Fever Patient ID 1123456 ES ES Notes bitten by spider Pharmacy jaspirin Twice a day Name Ilva Payne ES Treatment jant yenene Figure 24 Treat Fever Workitem detail Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 24 When the Treat Fever workitem is submitted the worklet case is completed The worklet service maps the output data from the worklet case to matching variables of the original Treat workitem then checks that workitem back in allowing the next workitem in the Casualty Treatm
36. tment 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 Worklet Custom Service User Manual Beta 7 Worklet_ User _Man_v0 7 doc 22 When the Triage workitem is submitted the next task in the process Treat becomes enabled Because it 1s worklet enabled the worklet service is notified The worklet 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 be 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 We have completed editing the Triage workitem and clicked the Submit button YE Go to the Available Work page Instead of seeing the next workitem listed 1 e Treat we see that Test Fever the first workitem in the TreatFever process is listed in its place Figure 21 The TreatFever process has been chosen by the worklet service to replace the Treat workitem based on the data passed to th
37. valid In a similar vein there is no option to modify or delete a rule node within a rule set tree 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 After all required fields have been entered click the Create button to create and YE save the new rule set Figure 16 shows the new rule set in the main Rules Editor screen as a result of the creation Worklet Rules Editor BookPurchase Saks File Rule Options Help Task GetBook ROR Tree Comerstone Case Rule 0 Title Breakfast of Champia e Author Kurt Vonnegut ES ISEN 586 04011 O Price 9 50 Stock Publisher Panther Books L Selected Mode Node ID 1 Parent Node ID 0 Condition Steck 0 8 Wiorklet OrderBook Description a book from the publishers when we have no stock available Figure 16 Example of a Newly Created Rule Set Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 19 4 Walkthrough Using the Worklet Service The worklet repository that comes with the worklet service release contains two example specifications with worklet enabled tasks each with an associated rule set and a number of associated worklets This section will step through the execution of these two examples A knowledge of how to use the YAWL system is assumed Before we begin make sure the worklet service is correctly installed and operational an
38. version If you don t have the framework installed it can be downloaded from Microsoft When the Rules Editor is run for the first time the following dialog is displayed Rules Editor First Time Configure Figure 7 Rules Editor First Time Use Message Clicking OK shows the Configuration dialog Figure 8 where the paths to resources the Rules Editor uses need 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 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 Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 10 YAWL Editor the path to the folder that contains the YAWL Editor 1 e the file YAWLEditor 3 jar Worklet Service URI the URI to the worklet service The default URI assumes it is installed locally If 1t is remote to the computer running the Rules Editor then that URI should be entered ensuring it ends with workletSelector Configure Paths Worklet Repository IC orkletsiepository a AML Editor CAYAMLAE ditor ne Worklet Service URI http localhost 8080 workletS elector Lancel Figure 8 Th
39. with the worklet service Worklet Custom Service User Manual Beta 7 Worklet_User_Man_v0 7 doc 4 YAWLEditor Specification Net Edit Elements Tools View Help Bely yla ala 8 Discharge Figure 1 Example Top level Specification Here we want to associate the Treat task with the worklet service To do that YE right click on the task then select Task Decomposition Detail from the popup menu The Update Task Decomposition dialog is shown Figure 2 This dialog 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 1s 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 Tre at Task Decomposition Variables Narre Type Usage Nane Input nly atientID ge ex eartRate ystolicBP iastolicBP eight Weight racture Fever boolear ash AbdominalPain ound harmacy Input Ontput reatment Notes YAWL Registered Service Detail TAWL Service Worklet bymamic P
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