Logging Optimistic Concurrency Exceptions: org.hibernate.StaleObjectStateException and JBPM

When it is running in a cluster configuration, the jBPM synchronizes with the database by using optimistic locking. This means that each operation is performed in a transaction and if, at the end, a collision is detected, then the transaction in question is rolled back and has to be handled with a retry. This can cause org.hibernate.StateObjectStateException exceptions. When this happens, Hibernate will log the exceptions with a simple message: optimistic locking failed

Hibernate can also log the StateObjectStateException with a stack trace:

15:35:07,123 [DispatcherThread] ERROR [AbstractFlushingEventListener] Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [org.jbpm.pvm.internal.job.TimerImpl#960071]
 at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1769)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2412)
 at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2312)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2612)
 at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:96)
 at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
 at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
 at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
 at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
 at org.jbpm.pvm.internal.tx.HibernateSessionResource.prepare(HibernateSessionResource.java:56)
 at org.jbpm.pvm.internal.tx.StandardTransaction.commit(StandardTransaction.java:107)
 at org.jbpm.pvm.internal.tx.StandardTransaction.complete(StandardTransaction.java:64)
 at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:57)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
 at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)
 at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.acquireJobs(DispatcherThread.java:126)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.run(DispatcherThread.java:67)

To remove these stack traces, set the org.hibernate.event.def.AbstractFlushingEventListener class to FATAL. Do so in log4j by using the following configuration:

log4j.logger.org.hibernate.event.def.AbstractFlushingEventListener=FATAL

Remember, this exception will not affect your process execution!, you can ignore it :)

Source: http://docs.redhat.com/docs/en-US/JBoss_Enterprise_SOA_Platform/5/html/JBPM_Reference_Guide

JBPM and Clustering

I'll be precise: "Can JBPM be deployed in a Distributed environment?"
In other words, Can I deploy multiple instances of JBPM? (but I want only 1 JVM to control all the executions)

My answer is Yes, you can have that mode! Just need to disable the JobExecutor on the other instances (by altering the configuration file)

<jbpm-configuration> <import resource="jbpm.businesscalendar.cfg.xml" /> <import resource="jbpm.console.cfg.xml" /> <import resource="jbpm.default.cfg.xml" /> <import resource="jbpm.identity.cfg.xml" /> <import resource="jbpm.task.lifecycle.xml" /> <import resource="jbpm.tx.hibernate.cfg.xml" /> <import resource="jbpm.variable.types.xml" /> <import resource="jbpm.bpmn.cfg.xml" /> <import resource="jbpm.bpmn.flownodes.xml" /> <import resource="jbpm.jpdl.cfg.xml" /> <!-- (start) --> <!-- Comment this entry on Clustered environments, enable this entry in ONE single JVM though and disable it on the others (4 JVMs in total: Enable it in 1 JVM and Disable it in 3) --> <process-engine-context> <job-executor threads="5" idle-max="60000" lock-millis="840000"/> </process-engine-context> <!-- (end) --> </jbpm-configuration>
Otherwise, you'll see this exception on your consoles (If your JVM's fight for the JOB's):

15:51:55,379 [DispatcherThread] ERROR [AbstractFlushingEventListener] Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [org.jbpm.pvm.internal.job.TimerImpl#385014]
 at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1769)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2412)
 at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2312)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2612)
 at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:96)
 at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
 at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
 at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
 at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
 at org.jbpm.pvm.internal.tx.HibernateSessionResource.prepare(HibernateSessionResource.java:56)
 at org.jbpm.pvm.internal.tx.StandardTransaction.commit(StandardTransaction.java:107)
 at org.jbpm.pvm.internal.tx.StandardTransaction.complete(StandardTransaction.java:64)
 at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:57)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
 at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)
 at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.acquireJobs(DispatcherThread.java:126)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.run(DispatcherThread.java:67)

If you're too lazy to have specific configuration per JVM, and you don't care about those exceptions, you're good to go (because that exception does not impact the Execution of your process instance), however, you can hide it by using Log4J (I'll explain that in another post)

Delegate to Seam the management of my JBPM4 engine

The problem was really simple, it's just implement a Singleton without writing it :P

I have a simple class, but I just need it to be loaded when the app starts, because my class will load the JBPM4 engine (and that should be done only once - this process may take up to 4 seconds, which will make really slow the first request coming to my End-Point)
But let me write more code and less words
Just add to your class these tags @Name("rtcapProcessExecutor") @Scope(ScopeType.APPLICATION) @Startup @BypassInterceptors @Install(precedence = Install.APPLICATION) public final class RtcapProcessRunner { .... }
Define which method will be your Creation method (Initialization method), on my case the one which will load the Engine @Create public void startup() { try{ log.info("Creating JBPM process engine using configuration file ("+GenericConstants.JBPM_CONFIG_FILE+") and Loading process definition ("+GenericConstants.PROCESS_DEFINITION_FILE+")"); this.processEngine = new Configuration().setResource(GenericConstants.JBPM_CONFIG_FILE).buildProcessEngine(); this.repositoryService = this.processEngine.getRepositoryService(); this.executionService = this.processEngine.getExecutionService(); this.repositoryService.createDeployment().addResourceFromClasspath(GenericConstants.PROCESS_DEFINITION_FILE).setName(GenericConstants.RTCAP).setTimestamp(new Date().getTime()).deploy(); }catch (Exception ex) { log.fatal("Error while loading RTCAP process definition and configuration file",ex); } }
Now the one which will Destroy your class (shutdown my JBPM4 engine) and release resources @Destroy public void shutdown() { log.info("Destroying JBPM process engine"); if (this.processEngine != null) { this.processEngine.close(); } }
and optionally, your Constructor @Constructor public RtcapProcessRunner(){ log.debug("Creating instance of RtcapProcessRunner"); }

Simple, Isnt' it?
Now you can inject this Seam Component using Injection into another Seam Component, just like this
@In(value="rtcapProcessExecutor", create=true, required=true) private RtcapProcessRunner rtcapProcessRunner; ... //And invoke any public method of that instance, just like this this.rtcapProcessRunner.executeProcessInstance(variablesMap, messageEntity); //And always will be the same instance (a Singleton!)

Fix javax.ejb.NoSuchEJBException: Could not find stateful bean on Seam and JBPM4

When I was using Google to look for answers to my problem, I found a lot of posts asking for a solution, just like me, but not a concrete answer (IMHO, JBoss has really poor documentation, compared with Spring, even their forums have less information), like this case

But I got a solution!!! (u_u)
Let me tell you my story...

On one of my Handlers I was using a ServiceImpl, just like this: public class UpdateStudentActionHandler extends BaseCustomJbpm4Handler implements ActivityBehaviour { private static final long serialVersionUID = 2971366515413177358L; private static Logger log = Logger.getLogger(UpdateStudentActionHandler.class); private IStudentDetailsService studentDetailsService; public void execute(ActivityExecution activityExecution) throws Exception { .... this.studentDetailsService = (IStudentDetailsService) this.getSeamComponentInstance("studentDetailsServiceBean"); try{ result = this.studentDetailsService.updateStudentDetails(studentDetails, enrollmentDetails); }catch (Exception ex) { .... } .... } }
This is my ServiceImpl @Name("studentDetailsServiceBean") @AutoCreate public class StudentDetailsServiceImpl implements IStudentDetailsService { private static Logger log = Logger.getLogger(StudentDetailsServiceImpl.class); @In(value="userDAO", create=true) private UserDAO userDAO; @In(value="studentIdLookupDAO", create=true) private StudentIdLookupDAO studentIdLookupDAO; @In(value="countryCodeDAO", create=true) private CountryCodeDAO countryCodeDAO; @In(value="deltakProductDAO", create=true) private DeltakProductDAO deltakProductDAO; @In(value="courseAccessHomeService", create=true) private CourseAccessHome courseAccessHomeService; @In(value="userCourseAccessDAO", create=true) private UserCourseAccessDAO userCourseAccessDAO; @In(value="productMixDAO", create=true) private ProductMixDAO productMixDAO; @In(value="componentAccessDAO", create=true) private ComponentAccessDAO componentAccessDAO; @In(value="courseAccessStatusDAO", create=true) private CourseAccessStatusDAO courseAccessStatusDAO; @In(value="courseAccessHsgDAO", create=true) private CourseAccessHsgDAO courseAccessHsgDAO; /* * Service method which will handle the Transaction */ @Transactional(TransactionPropagationType.REQUIRED) public Boolean updateStudentDetails(StudentDetails studentDetails, EnrollmentDetails enrollmentDetails) throws Exception { Boolean result = false; try{ User user = this.userDAO.lookupUserById(studentDetails.getUserId()); //Update user related data user = this.updateDpsTables(user, studentDetails, enrollmentDetails); //This one is common for Save and Update! CourseAccess courseAccess = this.saveCourseAccessData(user, enrollmentDetails); //For this phase we only SAVE enrollments/couseAccess - no need to update result = true; //Populate courseAccessId by reference enrollmentDetails.setCourseAccessId(courseAccess.getId()); }catch (Exception ex) { log.error("Error while Updating StudentDetails [studentId="+studentDetails.getStudentId()+", enrollmentId="+enrollmentDetails.getEnrollmentId()+"] into DB",ex); throw ex; } return result; } }
And my getSeamComponentInstance method protected Object getSeamComponentInstance(final String componentName){ //For Asyc Calls we have to do this to avoid "IllegalStateException: No event context active" when using Component.getInstance() if (!Contexts.isApplicationContextActive() && !Contexts.isEventContextActive() && !Contexts.isSessionContextActive()){ Lifecycle.beginCall(); } return Component.getInstance(componentName); }

As you can see, this doesn't have anything really weird, I just injecting a Bean into another class, and invoke one its methods! Simple (pure DI)

When you test it, it works! After it's been deployed, it works again, but...

After some period of inactivity... Boooom! The same line of code (the one where I invoke one of the methods of my ServiceImpl) was throwing an this

javax.ejb.NoSuchEJBException: Could not find stateful bean: 4sg5nl-4371oh-gsvwkdiv-1-gsvwst2j-1b
 at org.jboss.ejb3.cache.simple.SimpleStatefulCache.get(SimpleStatefulCache.java:492)
 at org.jboss.ejb3.cache.simple.SimpleStatefulCache.get(SimpleStatefulCache.java:443)
 at org.jboss.ejb3.stateful.StatefulInstanceInterceptor.invoke(StatefulInstanceInterceptor.java:61)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
 at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:106)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.stateful.StatefulContainer.localInvoke(StatefulContainer.java:204)
 at org.jboss.ejb3.stateful.StatefulLocalProxy.invoke(StatefulLocalProxy.java:117)
 at $Proxy81.afterTransactionRollback(Unknown Source)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
 at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:32)
 at org.jboss.seam.intercept.ClientSideInterceptor$1.proceed(ClientSideInterceptor.java:76)
 at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
 at org.jboss.seam.intercept.ClientSideInterceptor.invoke(ClientSideInterceptor.java:54)
 at org.javassist.tmp.java.lang.Object_$$_javassist_seam_5.afterTransactionRollback(Object_$$_javassist_seam_5.java)
 at org.jboss.seam.transaction.UTTransaction.rollback(UTTransaction.java:70)
 at org.jboss.seam.util.Work.workInTransaction(Work.java:68)
 at org.jboss.seam.transaction.TransactionInterceptor.aroundInvoke(TransactionInterceptor.java:91)
 at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
 at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
 at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
 at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
 at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185)
 at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103)
 at com.kaplan.service.impl.StudentDetailsServiceImpl_$$_javassist_seam_11.updateStudentDetails(StudentDetailsServiceImpl_$$_javassist_seam_11.java)
 at com.kaplan.jbpm.action.integration.jbpm4.UpdateStudentActionHandler.execute(UpdateStudentActionHandler.java:44)
 at org.jbpm.pvm.internal.wire.usercode.UserCodeActivityBehaviour.execute(UserCodeActivityBehaviour.java:42)
 at org.jbpm.pvm.internal.model.op.ExecuteActivity.perform(ExecuteActivity.java:60)
 at org.jbpm.pvm.internal.model.ExecutionImpl.performAtomicOperationSync(ExecutionImpl.java:672)
 at org.jbpm.pvm.internal.model.op.ExecuteActivityMessage.executeVoid(ExecuteActivityMessage.java:45)
 at org.jbpm.pvm.internal.job.MessageImpl.execute(MessageImpl.java:46)
 at org.jbpm.pvm.internal.job.MessageImpl.execute(MessageImpl.java:32)
 at org.jbpm.pvm.internal.cmd.ExecuteJobCmd.execute(ExecuteJobCmd.java:79)
 at org.jbpm.pvm.internal.cmd.ExecuteJobCmd.execute(ExecuteJobCmd.java:41)
 at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)
 at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:50)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
 at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)
 at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
 at org.jbpm.pvm.internal.jobexecutor.JobParcel.run(JobParcel.java:48)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
 at java.lang.Thread.run(Thread.java:619)

WTF!!!

What!!! I'm not even using stateful beans!!!, I'm using plain POJO's not even stateless!
This is how it works Seam, when you inject a Component using Components.getInstance, you just get a Proxy, and that proxy references the REAL instance of the class you want to invoke, but for any weird reason, that instance it has been removed! Then, why the freaking Proxy points to a nonexistent object? No idea (u_u).

Let's force Seam to create a new instance if it doesn't exist and specify that I don't want a Stateful bean by passing the scope Stateless (you can try with another one, but Stateless seems to be working just fine) and this is it
protected Object getSeamComponentInstance(final String componentName, final ScopeType scopeType){ //For Asyc Calls we have to do this to avoid "IllegalStateException: No event context active" when using Component.getInstance() if (!Contexts.isApplicationContextActive() || !Contexts.isEventContextActive() || !Contexts.isSessionContextActive() || !Contexts.isConversationContextActive() || !Contexts.isMethodContextActive()){ Lifecycle.beginCall(); } return Component.getInstance(componentName, scopeType, true); } public class UpdateStudentActionHandler extends BaseCustomJbpm4Handler implements ActivityBehaviour { private static final long serialVersionUID = 2971366515413177358L; private static Logger log = Logger.getLogger(UpdateStudentActionHandler.class); private IStudentDetailsService studentDetailsService; public void execute(ActivityExecution activityExecution) throws Exception { .... this.studentDetailsService = (IStudentDetailsService) this.getSeamComponentInstance("studentDetailsServiceBean", ScopeType.STATELESS); try{ result = this.studentDetailsService.updateStudentDetails(studentDetails, enrollmentDetails); }catch (Exception ex) { .... } .... } }

And after 1 night of inactivity, the error was gone (one for the team!)

StaleObjectStateException on JBPM4

When I was doing some testing to my recently implemented JBPM4 process, I faced a really ugly error, which ended abruptly my process :(

Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [org.jbpm.pvm.internal.job.TimerImpl#17]

After researching on Jboss.org, I just found very few bread crumbs instead of the whole slice of bread:
StaleObjectException on Timer execution
My process was different, because mine was completely ASYNC, then I realize, what would happen if I make SYNC just the WAIT state (which was causing the problem) and keep ASYNC my other states. After my first test, I got what I was expecting :D

Migrating to JBPM4

As you well know, I was using for one of my projects JBPM3, but then I decided to to jump into something more stable and even cool! (which will give me more automatization and the ability to recover from server crashes - in other words, restart a process previously interrupted :) )

The API changed completely, some classes were renamed others were removed, methods are not the same, configuration is different, in a few words "It doesn't have any relation with the previous version"

Cons:

You won't be able to keep your logs or comments on your tables, no more Transient variables, no more stoping process due to Exceptions, no more suspend or resume process (using the API), poor history of each execution - but it really helps what you see (if you want more details, I recommend you to use wisely your Log4J), if you don't believe me, look at my base handler after I migrated
public abstract class BaseCustomJbpm4Handler { /** * Retrieve a variable from the context * * @param name * @param executionContext * @return Object */ protected final Object getVariableFromContext(final String name, OpenExecution openExecution){ return openExecution.getProcessInstance().getVariable(name); } /** * Add a variable into the context<br> * <b>All variables to be added into the Context MUST Implement <code>java.io.Serializable</code> Interface</b> * * @param name * @param executionContext * @return Object */ protected final void setVariableIntoContext(final String name, Object value, OpenExecution openExecution){ openExecution.getProcessInstance().setVariable(name, value); } /** * Add a variable into the context and Keep track of it on JBPM4_HIST_VAR table<br> * <b>All variables to be added into the Context MUST Implement <code>java.io.Serializable</code> Interface</b> * * @param name * @param executionContext * @return Object */ protected final void createVariable(final String name, Object value, OpenExecution openExecution){ ((ExecutionImpl)openExecution).createVariable(name, value, "string", true); } /** * Retrieve a Transient variable from the context.<br>Transient variables are not stored in DB. * * @param name * @param executionContext * @return Object */ protected final Object getTransientVariableFromContext(final String name, OpenExecution openExecution){ return this.getVariableFromContext(name, openExecution);//Transient Variables NOT AVAILABLE on JBPM4 } /** * Add a Transient variable into the context.<br>Transient variables are not stored in DB.<br> * <b>All variables to be added into the Context MUST Implement <code>java.io.Serializable</code> Interface</b> * * @param name * @param executionContext * @return Object */ protected final void setTransientVariableIntoContext(final String name, Object value, OpenExecution openExecution){ this.setVariableIntoContext(name, value, openExecution);//Transient Variables NOT AVAILABLE on JBPM4 } /** * Retrieves a reference to a Seam session bean component stub, * which can then be used to remotely execute methods against your component.<br> * This method returns a singleton for the specified component, * so calling it twice in a row with the same component name * will return the same instance of the component.<br> * If the component doesn't exist, by default we're telling Seam to create a new instance. * * @param componentName * @param scopeType * @return Object */ protected Object getSeamComponentInstance(final String componentName, final ScopeType scopeType){ //For Asyc Calls we have to do this to avoid "IllegalStateException: No event context active" when using Component.getInstance() if (!Contexts.isApplicationContextActive() || !Contexts.isEventContextActive() || !Contexts.isSessionContextActive() || !Contexts.isConversationContextActive() || !Contexts.isMethodContextActive()){ Lifecycle.beginCall(); } return Component.getInstance(componentName, scopeType, true); } }

Pros:

Process definition is the same file which describes de Diagram spec (no more hidden files), configuration file is much simpler (the default params work really nice - It's almost ready for production out of the box), hibernate configuration is much easy to read, process could be started easily by using code (FEWER lines that in JBPM3), ASYNC process really work!, resume processes interrupted, you can define a business key for each execution - look into table JBPM4_HIST_PROCINST, Timer really works! - you'll see it on my process definition

This is how I started my process (due to my process is ASYNC, it doesn't wait until process is completed to return a response - which is great for Fire and Forget, obviously the first request will be the one which takes longer, because it will have to wait until everything is loaded but the next request will be super fast! - I've seen and Avg. of 70ms)
@Name("rtcapProcessExecutor") @Scope(ScopeType.APPLICATION) @Startup @BypassInterceptors @Install(precedence = Install.APPLICATION) public final class RtcapProcessRunner { private static Logger log = Logger.getLogger(RtcapProcessRunner.class); private ProcessEngine processEngine; private RepositoryService repositoryService; private ExecutionService executionService; /** * Initiates the jBPM Context * */ @Create public void startup() { try{ String jbpmConfigFile = GenericConstants.JBPM_RTCAP_DISABLED_CONFIG_FILE; if(BooleanUtils.toBoolean(System.getProperty(GenericConstants.RTCAP_ENABLED, "false"))){//Verify if JobExecutor is enabled in order to determine which config file to load jbpmConfigFile = GenericConstants.JBPM_RTCAP_ENABLED_CONFIG_FILE; } log.info("Creating JBPM process engine using configuration file ("+jbpmConfigFile+") and Loading process definition ("+GenericConstants.PROCESS_DEFINITION_FILE+")"); this.processEngine = new Configuration().setResource(jbpmConfigFile).buildProcessEngine(); this.repositoryService = this.processEngine.getRepositoryService(); this.executionService = this.processEngine.getExecutionService(); this.repositoryService.createDeployment().addResourceFromClasspath(GenericConstants.PROCESS_DEFINITION_FILE).setName(GenericConstants.RTCAP).setTimestamp(new Date().getTime()).deploy(); }catch (Exception ex) { log.fatal("Error while loading RTCAP process definition and configuration file",ex); } } /** * Close JBPM process engine */ @Destroy public void shutdown() { log.info("Destroying JBPM process engine"); if (this.processEngine != null) { this.processEngine.close(); } } @Constructor public RtcapProcessRunner(){ log.debug("Creating instance of RtcapProcessRunner"); } /** * Execute the process by creating a new ProcessInstance per call * * @param variablesMap * @param message */ public Boolean executeProcessInstance(Map<String, Object> variablesMap, MessageEntity message){ RtcapLogger.info(log, "Starting process instance for "+GenericConstants.ENROLLMENT_ID+"="+message.getEnrollmentId(), message.getMsgId()); Boolean result = false; ProcessInstance processInstance = null; try{ processInstance = this.executionService.startProcessInstanceByKey(GenericConstants.RTCAP, variablesMap, variablesMap.get(GenericConstants.ENROLLMENT_ID)+""); //Keep track of some variables on JBPM4_HIST_VAR table - Shows an error on console (which doesn't stop the execution): org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [org.jbpm.pvm.internal.model.ExecutionImpl#] this.executionService.createVariable(processInstance.getId() ,GenericConstants.MESSAGE_ID, variablesMap.get(GenericConstants.MESSAGE_ID), true); this.executionService.createVariable(processInstance.getId() ,GenericConstants.SYSTEM_NAME, variablesMap.get(GenericConstants.SYSTEM_NAME), true); }catch (Exception ex) { RtcapLogger.warn(log, "Error while starting process instance for "+GenericConstants.ENROLLMENT_ID+"="+message.getEnrollmentId(), ex, message.getMsgId()); message.setErrorMessage("Error while starting process instance for "+GenericConstants.ENROLLMENT_ID+"="+message.getEnrollmentId()+". Please contact System Administrator: "+ex.getMessage()); } if(processInstance!=null){ message.setProcessInstanceId(processInstance.getId()); message.setProcessDefinitionId(processInstance.getProcessDefinitionId()); } RtcapLogger.debug(log, "Control over the process delegated to JBPM engine", message.getMsgId()); return result; } }
My process definition is cleaner and I really like it <?xml version="1.0" encoding="UTF-8"?> <process key="RTCAP" name="myRTCAPv4" xmlns="http://jbpm.org/4.4/jpdl"> <start g="60,12,48,48" name="start"> <transition g="-53,-18" name="toVerifyParameters" to="Verify Parameters"/> </start> <end g="1224,576,48,48" name="end"/> <end-error g="781,180,169,52" name="end-error_EnrollmentNotEligible"/> <end-cancel g="60,456,169,52" name="end-cancel_ExistingEnrollment"/> <end-cancel g="516,36,48,48" name="end-cancel_MaxNumberAttemptsReached"/> <end-error g="768,456,48,48" name="end-error_ExceptionOnProcess"/> <custom class="com.kaplan.jbpm.action.integration.jbpm4.VerifyParamsActionHandler" continue="async" g="24,144,121,52" name="Verify Parameters"> <transition g="-76,-18" name="toEnrollmentExists?" to="Enrollment Exists?"/> </custom> <decision continue="async" g="60,288,48,48" name="Enrollment Exists?"> <handler class="com.kaplan.jbpm.decision.integration.jbpm4.EnrollmentExistDecisionHandler" /> <transition g="-60,-18" name="ExistingEnrollment" to="end-cancel_ExistingEnrollment"/> <transition g="-33,-22" name="NewEnrollment" to="Wait"/> </decision> <decision continue="async" g="516,144,60,48" name="Enrollment Details Available?"> <handler class="com.kaplan.jbpm.decision.integration.jbpm4.EnrollmentDetailsAvailableDecisionHandler" /> <transition g="288,169:-53,-18" name="NotAvailable" to="Wait"/> <transition g="637,167;637,62:-7,-70" name="Available" to="Is Eligible for Integration?"/> <transition g="-112,-2" name="maxNumberAttemptsReached" to="end-cancel_MaxNumberAttemptsReached"/> </decision> <state continue="async" g="240,288,97,52" name="Wait"> <transition g="288,408:9,-22" name="toRetrieveEnrollmentDetails" to="Retrieve Enrollment Details"> <timer duedate="10 minutes"/> <event-listener class="com.kaplan.jbpm.action.integration.jbpm4.WaitEventListener"/> </transition> </state> <custom class="com.kaplan.jbpm.action.integration.jbpm4.RetrieveEnrollmentDetailsActionHandler" continue="async" g="444,384,193,52" name="Retrieve Enrollment Details"> <transition g="-65,-17" name="toVerifyEnrollmentDetails" to="Enrollment Details Available?"/> </custom> <decision continue="async" g="781,36,97,52" name="Is Eligible for Integration?"> <handler class="com.kaplan.jbpm.decision.integration.jbpm4.EnrollmentEligibleDecisionHandler" /> <transition g="-53,-18" name="EnrollmentNotEligible" to="end-error_EnrollmentNotEligible"/> <transition g="-53,-18" name="EnrollmentEligible" to="Retrieve Student Details"/> </decision> <custom class="com.kaplan.jbpm.action.integration.jbpm4.RetrieveStudentDetailsActionHandler" continue="async" g="973,37,169,52" name="Retrieve Student Details"> <transition g="-93,-16" name="toStudentExists?" to="Student Exists?"/> </custom> <decision continue="async" g="1032,203,48,48" name="Student Exists?"> <handler class="com.kaplan.jbpm.decision.integration.jbpm4.StudentExistDecisionHandler" /> <transition g="907,281:-60,-18" name="NewStudent" to="Save Student Details"/> <transition g="1200,287:-8,-18" name="ExistingStudent" to="Update Student Details"/> </decision> <decision continue="async" g="1032,456,48,48" name="Course Access Is Available?"> <handler class="com.kaplan.jbpm.decision.integration.jbpm4.CourseAccessAvailableDecisionHandler" /> <transition g="-58,-16" name="courseAccessNotAvailable" to="end-error_ExceptionOnProcess"/> <transition g="-69,-18" name="courseAccessAvailable" to="Bulk Post"/> </decision> <custom class="com.kaplan.jbpm.action.integration.jbpm4.SaveStudentActionHandler" continue="async" g="831,324,152,52" name="Save Student Details"> <transition g="-136,-25" name="toCourseAccessAvailableFromSave" to="Course Access Is Available?"/> </custom> <custom class="com.kaplan.jbpm.action.integration.jbpm4.UpdateStudentActionHandler" continue="async" g="1127,324,152,52" name="Update Student Details"> <transition g="-53,-26" name="toCourseAccessAvailableFromUpdate" to="Course Access Is Available?"/> </custom> <custom class="com.kaplan.jbpm.action.integration.jbpm4.BulkPostActionHandler" continue="async" g="1008,576,97,52" name="Bulk Post"> <transition g="-47,-18" name="toEnd" to="end"/> </custom> </process>

Finally, let me show you a couple of Handlers, except for a few changes, I didn't change them a lot compared with my original JBPM3 code :) Cool beans!
public class CourseAccessAvailableDecisionHandler extends BaseCustomJbpm4Handler implements DecisionHandler { private static final long serialVersionUID = -4617542811826572467L; private static Logger log = Logger.getLogger(CourseAccessAvailableDecisionHandler.class); @Override public String decide(OpenExecution openExecution) { String messageId = (String)this.getVariableFromContext(GenericConstants.MESSAGE_ID, openExecution); StudentDetails studentDetails = (StudentDetails)this.getVariableFromContext(GenericConstants.STUDENT_DETAILS_KEY, openExecution); EnrollmentDetails enrollmentDetails = (EnrollmentDetails)this.getVariableFromContext(GenericConstants.ENROLLMENT_DETAILS_KEY, openExecution); String enrollmentId = (String)this.getVariableFromContext(GenericConstants.ENROLLMENT_ID, openExecution); String decision = null; RtcapLogger.debug(log, "Verify if Save or Update Student Details was executed successfully for "+studentDetails.toStringMinimal()+" and "+GenericConstants.ENROLLMENT_ID+"="+enrollmentId, messageId); if(StringUtils.isEmpty(enrollmentDetails.getCourseAccessId())){ RtcapLogger.warn(log, "CourseAccessId is NOT AVAILABLE, which means there was an error on the process", messageId); decision = GenericConstants.COURSE_ACCESS_NOT_AVAILABLE; }else{ RtcapLogger.info(log, "CourseAccessId is AVAILABLE, no errors during the process execution yet", messageId); decision = GenericConstants.COURSE_ACCESS_AVAILABLE; } RtcapLogger.debug(log, "Deciding what to do for "+studentDetails.toStringMinimal()+" and "+GenericConstants.ENROLLMENT_ID+"="+enrollmentId+"::Decision taken=" + decision, messageId); return decision; } }
public class SaveStudentActionHandler extends BaseCustomJbpm4Handler implements ActivityBehaviour { private static final long serialVersionUID = 6927651964198687636L; private static Logger log = Logger.getLogger(SaveStudentActionHandler.class); private IStudentDetailsService studentDetailsService; public void execute(ActivityExecution activityExecution) throws Exception { Boolean result = false; StudentDetails studentDetails = (StudentDetails)this.getVariableFromContext(GenericConstants.STUDENT_DETAILS_KEY, activityExecution); EnrollmentDetails enrollmentDetails = (EnrollmentDetails)this.getVariableFromContext(GenericConstants.ENROLLMENT_DETAILS_KEY, activityExecution); String messageId = (String)this.getVariableFromContext(GenericConstants.MESSAGE_ID, activityExecution); RtcapLogger.debug(log, "Execute for " +studentDetails, messageId); this.studentDetailsService = (IStudentDetailsService) this.getSeamComponentInstance("studentDetailsServiceBean"); try{ RtcapLogger.info(log, "Saving "+studentDetails.toStringMinimal(), messageId); result = this.studentDetailsService.saveStudentDetails(studentDetails, enrollmentDetails); }catch (Exception ex) { RtcapLogger.error(log, GenericConstants.ERROR_MSG_STUDENT_DETAILS_BEAN+" [studentId="+studentDetails.getStudentId()+","+GenericConstants.ENROLLMENT_ID+"="+enrollmentDetails.getEnrollmentId()+"]", ex, messageId); this.raiseException(activityExecution, new Exception(GenericConstants.ERROR_MSG_STUDENT_DETAILS_SAVING+" [studentId="+studentDetails.getStudentId()+","+GenericConstants.ENROLLMENT_ID+"="+enrollmentDetails.getEnrollmentId()+"] In "+SaveStudentActionHandler.class.getName(), ex.getCause())); } if(!result){ RtcapLogger.fatal(log, GenericConstants.ERROR_MSG_STUDENT_DETAILS_SAVING+" [studentId="+studentDetails.getStudentId()+","+GenericConstants.ENROLLMENT_ID+"="+enrollmentDetails.getEnrollmentId()+"]", messageId); this.raiseException(activityExecution, new Exception(GenericConstants.ERROR_MSG_STUDENT_DETAILS_SAVING+" [studentId="+studentDetails.getStudentId()+","+GenericConstants.ENROLLMENT_ID+"="+enrollmentDetails.getEnrollmentId()+"]")); }else{ RtcapLogger.info(log, "StudentDetails saved successfully!", messageId); } } }

Building from source BPM Console (for JBPM4)

For some personal reasons I wanted to customize the JBPM Console, so the only way to do it is by building from source code.
The first thing I had to do is get the sources and compile them using Maven :)

If by any chance you're having a hard time with this error (like me)

[ERROR] Failed to execute goal on project gwt-console: Could not resolve dependencies for project org.jboss.bpm:gwt-console:war:2.2.3-Final: The following artifacts could not be resolved: org.timepedia.chronoscope:chronoscope:jar:2.0_jboss-SNAPSHOT, org.timepedia.chronoscope:chronoscope-api:jar:2.0_jboss-SNAPSHOT: Failure to find org.timepedia.chronoscope:chronoscope:jar:2.0_jboss-SNAPSHOT in https://repository.jboss.org/nexus/content/groups/public/ was cached in the local repository, resolution will not be reattempted until the update interval of jboss-public-repository-group has elapsed or updates are forced -> [Help 1]

Just do as I did. Go to Maven Hub and search for your missing jar, on my case I found it on Thirdparty-uploads repository (from JBoss);

Unfortunately, the version I was looking for (according to the previous error) was chronoscope:jar:2.0_jboss-SNAPSHOT and I found 2.0_jboss, I guess you know what to do now, don't you?

Just cheat Maven by installing on your local repository version "2.0_jboss" as "2.0_jboss-SNAPSHOT"

Voila!!!

As result you should get these 4 artifacts:

• Console UI: gwt-console.war
• Console Server: gwt-console-server.war
• Domain model: gwt-console-rpc.jar
• Integration Layer: gwt-console-server-integration.jar

Also, don't forget to include the bpaf-explorer jars. To avoid this:

14:52:32,728 [main] ERROR [ContainerBase] StandardWrapper.Throwable
com.google.inject.ProvisionException: Guice provision errors:

1) Error injecting constructor, java.lang.NoClassDefFoundError: org/jboss/bpm/monitor/model/metric/Timespan
  at org.jboss.errai.bus.server.service.ErraiServiceImpl.(ErraiServiceImpl.java:50)
  while locating org.jboss.errai.bus.server.service.ErraiServiceImpl
  while locating org.jboss.errai.bus.server.service.ErraiService

1 error
 at com.google.inject.InjectorImpl$4.get(InjectorImpl.java:767)
 at com.google.inject.InjectorImpl.getInstance(InjectorImpl.java:793)
 at org.jboss.errai.bus.server.servlet.AbstractErraiServlet.buildService(AbstractErraiServlet.java:117)
 at org.jboss.errai.bus.server.servlet.AbstractErraiServlet.init(AbstractErraiServlet.java:88)
 at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1161)

My first encounter with jBPM

Long story, short story. When I was working in one of my projects in Mexico, somebody mentioned something about BPM or BPEL and how practical de idea/concept was, because now we can mix the knowledge of the Business People with the Developers, by using some kind of cool diagrams to do Process Modeling.

And now I had to create a project which essentially it's a WorkFlow but we need some features like keeping the state of each execution (so we can trace it easily and resume the process if by any chance is stopped) "et all" and then, when I saw that One of the requirements was to integrate this miniworkflow with an existing App deployed on jBoss 4 with Seam 2.1 (I'd talk later about this framework, for all those like me who love Spring Framework), then I have to use jBPM 3 instead of 4 or 5 OUCH :'(
"But then, I realize that JBPM4 can work flawlessly on JBoss 4"
What do we need???
No much, Eclipse Helios (3.6)
Install these features:

• JBoss Tools - http://download.jboss.org/jbosstools/updates/development/helios (don't forget to install jBPM support!)
• Graphiti - http://download.eclipse.org/graphiti/updates/0.7.1
• BPMN2 - http://codehoop.com/bpmn2

The concept is really simple, we just need to model the flow (I'll use the Designer to do this)

But it needs some logic inside its guts, so I'll add something called Handlers and some personalized tags (which is a really cool feture)
This is our model translated into XML <?xml version="1.0" encoding="UTF-8"?> <process-definition xmlns="urn:jbpm.org:jpdl-3.2" name="myRTCAP"> <start-state name="start"> <transition to="Verify Enrollment"/> </start-state> <state name="Verify Enrollment"> <transition to="Enrollment Exists?"> <action class="com.kaplan.rtcap.action.VerifyEnrollmentActionHandler"/> </transition> </state> <state name="Retrieve Enrollment Details"> <transition to="Save Enrollment Details"> <action class="com.kaplan.rtcap.action.SaveEnrollmentDetailsActionHandler"/> </transition> </state> <state name="Save Enrollment Details"> <transition to="Retrieve Student Details"/> </state> <state name="Retrieve Student Details"> <transition to="Student Exists?"> <action class="com.kaplan.rtcap.action.RetrieveStudentDetailsActionHandler"/> </transition> </state> <state name="Save Student Details"> <event type="node-enter"> <action class="com.kaplan.rtcap.action.SaveStudentActionHandler"/> </event> <transition to="Bulk Post"/> </state> <state name="Update Student Details"> <event type="node-enter"> <action class="com.kaplan.rtcap.action.UpdateStudentActionHandler"/> </event> <transition to="Bulk Post"/> </state> <state name="Bulk Post"> <event type="node-enter"> <action class="com.kaplan.rtcap.action.BulkPostActionHandler"/> </event> <transition to="end" /> </state> <decision name="Enrollment Exists?"> <handler class="com.kaplan.rtcap.action.decision.EnrollmentExistDecisionActionHandler"/> <transition name="ExistingEnrollment" to="end"> <action class="com.kaplan.rtcap.action.EnrollmentExistActionHandler" /> </transition> <transition name="NewEnrollment" to="Retrieve Enrollment Details" > <action class="com.kaplan.rtcap.action.RetrieveEnrollmentDetailsActionHandler"/> </transition> </decision> <decision name="Student Exists?"> <handler class="com.kaplan.rtcap.action.decision.StudentExistDecisionActionHandler"/> <transition name="NewStudent" to="Save Student Details"/> <transition name="ExistingStudent" to="Update Student Details"/> </decision> <end-state name="end"> <event type="node-enter"> <script>System.out.println("End of the process")</script> </event> </end-state> </process-definition>
On my implementation, the process will run by itself, it's going to be a "FIRE AND FORGET";

On my case the process will wait for a certain amount of time and the it will start, it'll make one decision and it will execute something and then the End :)
<state name="Wait"> <transition to="Verify Enrollment" name="toVerifyEnrollment"> <action class="com.kaplan.jbpm.action.rtcap.WaitActionHandler"> <minutes>0</minutes> <seconds>0</seconds> </action> </transition> </state>
The logic will be implemented by Implementing some Interfaces:
org.jbpm.graph.def.ActionHandler org.jbpm.graph.node.DecisionHandler
public class WaitActionHandler extends BaseCustomHandler implements ActionHandler { private static Logger log = Logger.getLogger(WaitActionHandler.class); private static final long serialVersionUID = 1L; private Integer seconds = 0; private Integer minutes = 0; public void execute(ExecutionContext executionContext) throws Exception { String enrollmentId = (String)this.getVariableFromContext(GenericConstants.ENROLLMENT_ID, executionContext); //Calculate waiting time Long time = 0L; if(minutes>0){ time = minutes*(60*1000L) + (seconds*1000L); }else{ time = seconds*1000L; } if(time>=1000){//If pause was at least 1 second show this logging message log.debug("Waiting for "+GenericConstants.ENROLLMENT_ID+"="+enrollmentId+", during "+minutes+"min "+seconds+"sec"); //Suspend (Pause) Process execution this.suspendExecution(executionContext); //Wait Thread.sleep(time); log.debug("Resuming process for "+GenericConstants.ENROLLMENT_ID+"="+enrollmentId); //Resume this.resumeExecution(executionContext); } }
public class VerifyEnrollmentActionHandler extends BaseCustomHandler implements ActionHandler { private static Logger log = Logger.getLogger(VerifyEnrollmentActionHandler.class); private static final long serialVersionUID = 1L; public void execute(ExecutionContext executionContext) throws Exception { //TODO: This class only demonstrates that the flow is being followed : Nothing important happens here! String enrollmentId = (String)this.getVariableFromContext(GenericConstants.ENROLLMENT_ID, executionContext); log.debug("Execute for "+GenericConstants.ENROLLMENT_ID+"="+enrollmentId); } }
public class StudentExistDecisionActionHandler extends BaseCustomHandler implements DecisionHandler { private static final long serialVersionUID = -902776688182390371L; private static Logger log = Logger .getLogger(StudentExistDecisionActionHandler.class); @In(value="studentIdLookupDAO") //Use Component.getInstance("purchaseDao") instead private StudentIdLookupDAO studentIdLookupDAO; public String decide(ExecutionContext executionContext) throws Exception { StudentDetailsVO studentDetails = (StudentDetailsVO)this.getVariableFromContext(GenericConstants.STUDENT_DETAILS_KEY, executionContext); String decision = null; List<StudentIdLookup> listStudentIdLookup = new ArrayList<StudentIdLookup>(); log.debug("Using Annotations: "+studentIdLookupDAO); this.studentIdLookupDAO = (StudentIdLookupDAO) Component.getInstance("studentIdLookupDAO"); log.debug("Using Seam.componentForName: "+studentIdLookupDAO); //TODO: Check if this Student already exists on STUDENT_ID_LOOKUP to determine if is NEW or EXISTING (SAVE or UPDATE) try{ listStudentIdLookup = studentIdLookupDAO.getByStudentId(studentDetails.getStudentId()); }catch (Exception ex) { log.error("Error while calling studentIdLookupDAO",ex); } if (!listStudentIdLookup.isEmpty()) { decision = GenericConstants.EXISTING_STUDENT; } else { decision = GenericConstants.NEW_STUDENT; } log.debug("Deciding what to do in for "+studentDetails+"\tDecision taken = " + decision); return decision; } } And Voila!!!

Soon I'll talk a little bit about jBoss SEAM! (How I implemented a REST Service FACILITO!)

No logging to JBPM_LOG when process instance ends | jBPM | JBoss Community

No logging to JBPM_LOG when process instance ends | jBPM | JBoss Community