How to set the application context and classloader for a process engine

alexd1 — Tue, 14 Jan 2014 16:39:32 GMT

Hi,I am having an issue creating a process engine that can both see all of its classes and my beans in my application context. I noticed that the Spring process engine configuration is application context aware, but it doesn't have a way for me to set the class loader. On the other side, the org.act

Re: How to set the application context and classloader for a process engine

trademak — Tue, 14 Jan 2014 23:49:45 GMT

Do you have a specific class loader then? Could you explain a bit more why you need that.

Best regards,

Re: How to set the application context and classloader for a process engine

alexd1 — Wed, 15 Jan 2014 00:41:35 GMT

I am using activiti in an application that manages several application contexts in a cloud. The application context's class loader is the one I want. I can set it using the method above, but I don't see a way to set an application context as well.

If I don't set the classloader, activiti can't find any of its classes. If I do set the class loader, I get property not found exceptions when activiti executes delegate expressions because it doesn't know any of the beans, so it looks like to me, all it needs is the application context once it has the right class loader.

Re: How to set the application context and classloader for a process engine

alexd1 — Wed, 15 Jan 2014 00:59:42 GMT

I'm using activiti 5.14

Here's how i'm initializing the process engine. I'm doing it this way to be able to set both the classloader & the application context. It doesn't look like it using the loader I set.

<java>
SpringProcessEngineConfiguration conf = new SpringProcessEngineConfiguration();
conf.setDataSource(dataSource);
conf.setTransactionManager(transactionManager);
conf.setDatabaseSchemaUpdate("true");
conf.setJobExecutorActivate(false);
conf.setClassLoader(applicationContext.getClassLoader());
conf.setTransactionsExternallyManaged(true);
ProcessEngineFactoryBean factorybean = new ProcessEngineFactoryBean();
factorybean.setApplicationContext(applicationContext);
factorybean.setProcessEngineConfiguration(conf);

ProcessEngine processEngine = null;
try {
   processEngine = factorybean.getObject();
} catch (Exception e1) {
   logger.debug("Exception occurred while creating the process engine");
   e1.printStackTrace();
}
ProcessEngines.registerProcessEngine(processEngine);
</java>

<code>
org.activiti.engine.ActivitiException: Error while evaluating expression: #{kbaDelegate.execute(execution)}
        at org.activiti.engine.impl.el.JuelExpression.getValue(JuelExpression.java:59)
        at org.activiti.engine.impl.bpmn.behavior.ServiceTaskExpressionActivityBehavior.execute(ServiceTaskExpressionActivityBehavior.java:45)
        at org.activiti.engine.impl.pvm.runtime.AtomicOperationActivityExecute.execute(AtomicOperationActivityExecute.java:44)
        at org.activiti.engine.impl.interceptor.CommandContext.performOperation(CommandContext.java:85)
        at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperationSync(ExecutionEntity.java:535)
        at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:530)
        at org.activiti.engine.impl.pvm.runtime.AtomicOperationTransitionNotifyListenerStart.eventNotificationsCompleted(AtomicOperationTransitionNotifyListe
…
Caused by: org.activiti.engine.impl.javax.el.ELException: Could not find expression factory class
        at org.activiti.engine.impl.javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:209)
        at org.activiti.engine.impl.javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:183)
        at org.activiti.engine.impl.javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:89)
        at org.activiti.engine.impl.javax.el.BeanELResolver.getExpressionFactory(BeanELResolver.java:527)
        at org.activiti.engine.impl.javax.el.BeanELResolver.invoke(BeanELResolver.java:479)
        at org.activiti.engine.impl.javax.el.CompositeELResolver.invoke(CompositeELResolver.java:397)
        at org.activiti.engine.impl.juel.AstMethod.invoke(AstMethod.java:91)
        at org.activiti.engine.impl.juel.AstMethod.eval(AstMethod.java:75)
        at org.activiti.engine.impl.juel.AstEval.eval(AstEval.java:50)
        at org.activiti.engine.impl.juel.AstNode.getValue(AstNode.java:26)
        at org.activiti.engine.impl.juel.TreeValueExpression.getValue(TreeValueExpression.java:114)
        at org.activiti.engine.impl.delegate.ExpressionGetInvocation.invoke(ExpressionGetInvocation.java:33)
        at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:37)
        at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:25)
        at org.activiti.engine.impl.el.JuelExpression.getValue(JuelExpression.java:50)
        … 212 more
Caused by: java.lang.ClassNotFoundException: org.activiti.engine.impl.juel.ExpressionFactoryImpl
        at org.grails.plugins.tomcat.ParentDelegatingClassLoader.findClass(ParentDelegatingClassLoader.java:59)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at org.activiti.engine.impl.javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:204)
        … 226 more
</code>

Re: How to set the application context and classloader for a process engine

frederikherema1 — Wed, 15 Jan 2014 09:06:52 GMT

Why do you need a custom class loader? Are you sure the activiti-engine is on that classloader's classpath?

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How to set the application context and classloader for a process engine

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Re: How to set the application context and classloader for a process engine

Re: How to set the application context and classloader for a process engine

Re: How to set the application context and classloader for a process engine