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Spring bean access in tasks and muiltiple ProcessEngines

Question asked by bwd on Apr 6, 2011
Latest reply on Apr 8, 2011 by frederikheremans1
Hi,

We're taking the approach of running multiple ProcessEngines in a single app server (each with a DataSource pointing to a different database schema) to provide multi-tenant support in an application.  We need to spin up engines on demand as customers come in, so we can't pre-configure them beforehand in the Spring configuration files.

I'm now able to build the ProcessEngines programatically instead of through Spring configuration, but i'm now finding that the Spring beans that I was previously accessing in BPMN expressions are no longer available.

Example configuration:

   <userTask activiti:candidateUsers="${groupBean.getCandidateUsers(execution,'blah')}" …

Example output when test is run:

Caused by: org.activiti.engine.impl.javax.el.PropertyNotFoundException: Cannot resolve identifier 'groupBean'
   at org.activiti.engine.impl.juel.AstIdentifier.eval(AstIdentifier.java:83)
   at org.activiti.engine.impl.juel.AstMethod.invoke(AstMethod.java:79)
   at org.activiti.engine.impl.juel.AstMethod.eval(AstMethod.java:75)
        …

The error makes sense:  Spring can't inject the beans used in the expression as it isn't creating the ProcessEngine instance.

Question:  Is there another 'blessed' programatic way to make a ProcessEngine aware of such beans if the Spring approach is no longer available?

I looked through the Activiti source and found the following method on org.activiti.spring.ProcessEngineFactoryBean:

  public ProcessEngine getObject() throws Exception

The implementation of this makes the following call

      processEngineConfiguration.setExpressionManager(
        new SpringExpressionManager(applicationContext, processEngineConfiguration.getBeans()));

which looks like it might do the trick, but when I add this to my code that builds the ProcessEngine, it still can't see the beans.

FYI - I'm using Activiti 5.4.

Thanks,

bwd

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