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jBPM5 Community Training Module #5: Domain Specific Processes


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This modules covers two different aspects that we need to understand to customize our business processes to specific business situations. The first concept that we need to understand is the Service Task activity defined in the BPMN v2 specification. Once we understand the nature of external system interactions we need to understand the mechanisms implemented in jBPM5 to provide these extension points.
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jBPM5 Community Training Module #5: Domain Specific Processes

  1. 1.    jBPM5 Community Training Sponsored by Plugtree
  2. 2. Module 5: jBPM5 Domain Specific Processes jBPM5 Community Training version: 1.0-SNAPSHOT Release Date: 03/01/2011Under The Creative Common License
  3. 3. Module 5: Domain Specific ProcessesjBPM5 Community Training Course by Mauricio "Salaboy" Salatino and Esteban Aliverti is licensed under a Creative Commons Attribution 3.0 Unported License.Based on a work at salaboy.wordpress. com. Permissions beyond the scope of this license may be available at http: //
  4. 4. AgendaDomain Specific Processes Introduction BPMN2 Service Tasks Work Item Concept inside jBPM5Work Items characteristicsWork Item Handlers Implementing Custom Handlers Controlling Flow ExecutionExamples
  5. 5. IntroductionBPMS are domain agnostic, thats good but... We need to extend them in order to represent specific business situations Our processes needs to represent domain specific behavior The activities inside our processes reflect how people work in a specific domain Different systems behaves differently and we need to represent this particular behavior in our processes
  6. 6. IntroductionThe BPMN2 Standard Specification Service Task It provides a generic way to interact with external servicesSpec: "A Service Task is a Task that uses some sort ofservice, which could be a Web service or an automatedapplication."We can use the Service Task concept as extension point toplug domain specific behavior and to handle externalinteractions
  7. 7. IntroductionInside jBPM5 the concept of Work Item is used forextension points Any external interaction from the process perspective is done via a Work Item The work item is executed outside the process scope A Work Item Handler needs to be defined to technically specify the execution behavior At runtime we can plug different implementations for different environments
  8. 8. Work Items CharacteristicsWork Items Represent a unit of work executed outside the process engine Main Characteristics: Domain-specific Declarative: what, not how High-level: no code Customizable to the context
  9. 9. Service Task relationship with WorkItemsService Task relationship with WorkItems The Service Task Activity inside BPMN2 exposes an atribute called: implementation: this attribute can be used to specify which implementation will be called when a specific service task is reached by the process execution. In jBPM5 this implementation attribute will be bond to a specific Work Item Handler that will contain the technical specification about how to interact with an external entity
  10. 10. Service Task relationship with WorkItemsService Task relationship with WorkItems (cont.) The Service Task activity define the information that will be required by the external interaction and how it will be copied from the process scope to the task scope The Service Task activity define the information that will be generated by the external interaction and needs to be copied back to the process scope
  11. 11. Service Task relationship with WorkItemsService Task relationship with Work Items (cont.) For each Service Task that we define in our process we need to have at least one WorkItemHandler implementation that must be bound before we execute our process At runtime we can choose which implementation will be used for each Service Task
  12. 12. WorkItems and WorkItemHandlersWorkItem and WorkItemHandlers For each external interaction that our process execute we need to know that a WorkItem will be executed The engine provides some built in work item handlers for common use cases Human Task WorkItemHandler is in charge of handling the human task creations in the Human Task Server Email WorkItemHandler is in charge of getting the information and interacts with an email server to send an email
  13. 13. WorkItemHandler InterfaceWorkItemHandler Interface org.drools.runtime.process.WorkItemHandler Its located inside an org.drools package because Drools and jBPM5 share the same mechanism for external interactions Force us to implement only two methods: public void executeWorkItem(WorkItem wi, WorkItemManager wim); public void abortWorkItem(WorkItem wi, WorkItemManager wim);
  14. 14. WorkItemHandler InterfaceWorkItemHandler Interface We can choose and define the behavior of the interaction inside the executeWorkItem(...) method The interaction can be synchronous or asynchrnous We usually do the following things inside the executeWorkItem(...) method: We get the information required by the interaction using the WorkItemManager We execute the interaction with an External (to the process) Service We complete the workItem syncronously or we delegate the completion to the external asynchronous system
  15. 15. WorkItemHandler BindingWorkItemHandler Binding We need to get the WorkItemManager from our Knowledge Session and register our WorkItemHandlers implementations ksession.getWorkItemManager() .registerWorkItemHandler(key,impl); When a running process hits and activity that specify the implementation registered (key) the work item handler will be executed (the executeWorkItem(...) method).
  16. 16. Synchronous WorkItemHandlerSynchronous Work Item Handler Executes the task When its finished, it can complete or abort the Work Item using the Work Item Manager methods
  17. 17. Asynchronous WorkItemHandlerAsynchronous Work Item Handler Call external service Delegate the responsibility to the external service app/service to complete or abort the Work Item For this reason the external app/service needs to have access to the session that has the Work Item Manager to complete or abort the Work Item
  18. 18. Asynchronous & Synchronous Interactions
  19. 19. Synchronous External Interactions
  20. 20. Asynchronous External Interactions
  21. 21. Async & Sync External Interactions
  22. 22. Asynchronous WorkItemHandlerOnce Asynchronous Work Item Handler Call external service Delegate the responsibility to the external service app/service to complete or abort the Work Item For this reason the external app/service needs to have access to the session that has the Work Item Manager to complete or abort the Work Item
  23. 23. Asynchronous WorkItemHandler Asynchronous Work Item Handler (cont.) We can implement a simple mechanism to keep track of the external async jobs We need to store a business key and the workItemId that needs to be finished when the application ends the async jobThis mechanism needs to have access to the knowledge sessionin order to be able to complete the related work item
  24. 24. Vehicle Tracking External Interaction
  25. 25. WorkItemHandler Information ScopeProcess execution will handle different pieces of informationWorkItemHandlers are considered to be external to theprocess scope and for that reason they have a limited scopeto handle informationWe need to manually map the information that it is requiredby the external interaction to be copied from the processscope to the WorkItemHandler scopeWhen we complete a WorkItem we get the results for theexternal interactionWe must map manually the information that needs to becopied back from the workItemHandler scope to the processscope
  26. 26. WorkItemHandler Information Mappings
  27. 27. Information Mappings in BPMN 2.0<ioSpecification> <dataInput id="_5_vehicle.typeInput" name="vehicle.type" /> <dataInput id="_5_vehicle.idInput" name="" /> <dataOutput id="_5_trackingIdOutput" name="trackingId" /> <dataOutput id="_5_trackingExecutionTimeOutput" name="trackingExecutionTime"/> <inputSet> <dataInputRefs>_5_vehicle.typeInput</dataInputRefs> <dataInputRefs>_5_vehicle.idInput</dataInputRefs> </inputSet> <outputSet> <dataOutputRefs>_5_trackingIdOutput</dataOutputRefs> <dataOutputRefs> _5_trackingExecutionTimeOutput </dataOutputRefs> </outputSet></ioSpecification>
  28. 28. Information Mappings in BPMN 2.0<dataInputAssociation> <targetRef>_5_vehicle.typeInput</targetRef> <assignment> <from xs:type="tFormalExpression">#{vehicle.type}</from> <to xs:type="tFormalExpression">_5_vehicle.typeInput</to> </assignment></dataInputAssociation><dataInputAssociation> <targetRef>_5_vehicle.idInput</targetRef> <assignment> <from xs:type="tFormalExpression">#{}</from> <to xs:type="tFormalExpression">_5_vehicle.idInput</to> </assignment></dataInputAssociation><dataOutputAssociation> <sourceRef>_5_trackingIdOutput</sourceRef> <targetRef>trackingId</targetRef></dataOutputAssociation><dataOutputAssociation> <sourceRef>_5_trackingExecutionTimeOutput</sourceRef> <targetRef>trackingExecutionTime</targetRef></dataOutputAssociation>
  29. 29. Examples Project: 02 - Emergency Service Process and Work Items Examples Key points: Synchronous Work Items Handler URL: git:// git Project: 03 - Emergency Service Process and Asynchronous Work Items Examples Key points: Asynchronous Work Items HandlerURL: git://
  30. 30. Examples: Emergency Service ProcessA new node was added: "Vehicle Tracking (GPS)"Task Activity represents a Task that needs to beperformed by an external systemYou need to register a handler for each TaskHandlers could be Synchronous or Asynchronous
  31. 31. Examples02 - Emergency Service Process and Work Items Examples: Handlers must implement org.drools.runtime.process. WorkItemHandler Handlers are registered in the Work Item Manager: ksession.getWorkItemManager(). registerWorkItemHandler( "StartTrackingSystem", trackingSystemHandler ); The handler completes the Work Item inside the executeWorkItem() method -> Synchronous behavior
  32. 32. Examples03 - Emergency Service Process and Asynchronous WorkItems Examples: Interaction between 3 different "Systems": EmergencyProcessExternalSystemsWorkItemsTest: Test application that embeds jBPM5 runtime. AsyncVehicleTrackingMockSystem: An external system in charge of tracking vehicles. ActiveWorkItemService: Service used to register and complete Work Items. This system maintains the relation between an External Job and a Work Item. The handler doesnt completes the Work Item inside the executeWorkItem() method -> Asynchronous behavior
  33. 33. HomeworkHomework Add a new output parameter to VehicleTrackingSystem task and show its value into the final report. This parameter should contain a String representation of the Date when the External Task was completed. Create an external system mock with an isAdmisible (trackingTime:long):boolean method. This method will receive the total tracking time and will return true if the total time is below a given (harcoded) threshold otherwise it will return false . Add a new "Call to Validation Service" task after VehicleTrackingSystem and create a synchronous handler that invokes the new system. The final report must contain the value returned by this system.
  34. 34. HomeworkHomework Hints: In order to define a new output parameter for a Task activity and to store its value in a process variable you need 4 steps: Create a new <itemDefinition> element. Create a new <property> in the process. Add a new <dataOutput> element in the Task Add a new <dataOutputAssociation> in the Task to map the output parameter to a process variable.
  35. 35. Homeworks SolutionsHomework Solutions Send me your homework solutions to my personal email Use the subject [JBPM5 Community Training] - Hands On labs 2 If you have doubts about the exercise, post a comment in the blog If I start receiving too much questions we can probably create a google group for answering questions or use the JBoss jBPM forum
  36. 36. ConclusionsConclusions We understand how to plug our custom domain specific behavior into our business processes We understand internal concepts that are implemented in jBPM5 that provides extension points for our external interactions We play with a couple of examples that show a very basic interaction and more realistic scenarios
  37. 37. Next ModulesStay tuned for the next modules that will explain importanttopics such as: The Business Process Modeling and Notation V2 Real Human Interactions inside our processes Task List Oriented User interfaces using different technologies etc.
  38. 38. Related LinksYou can find more information, examples, tutorials andmore in: Salaboy Blog Esteban Blog Plug Tree Blog
  39. 39.    Questions?
  40. 40. Enjoy! Questions and Feedback arealways appreciated!
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