topic Re: epressionManager property in ProcessEngineConfiguration in Alfresco Archive

epressionManager property in ProcessEngineConfiguration

ptriller — Wed, 09 Feb 2011 11:48:18 GMT

Hello,I am trying to give the Tasks in the engine a few context services which I can call from scripts and ELExpression,for this I set an expressionManager inmy activity.cfg.xmlbut after debuggingaround in the code a bit, I saw, that the manager is not used,Is this italways uses the createElContext

Re: epressionManager property in ProcessEngineConfiguration

frederikherema1 — Wed, 09 Feb 2011 11:56:40 GMT

Hi,

The expression-manager is only used for resolving 'Expressions'. The Scripting uses another mechanism to introduce variables to the script-context, the Bindings (org.activiti.engine.impl.scripting.ExecutionBindings).

These bindings are created "ScriptEngines", and currently don't have an easy access-point to add custom things, related issues:
http://jira.codehaus.org/browse/ACT-97
http://jira.codehaus.org/browse/ACT-438

Re: epressionManager property in ProcessEngineConfiguration

ptriller — Wed, 09 Feb 2011 12:13:41 GMT

thanks for your quick answer.

Any workaround you can think of, so I can call service methods in Juel ?

If I use groovy scripts in Script Tasks, I can just use static methods, so that is managable,
but Juel does not allow that IIRC, so putting the result of some mehtod calls
in Forms is not possible, I just want to put some live status into the form
of a user task which is obtained by a service call.

Any idea ?

Re: epressionManager property in ProcessEngineConfiguration

frederikherema1 — Wed, 09 Feb 2011 12:57:17 GMT

Hi,

Only workaround I can think of is this:
You can plug in your own FormEngine (pointer on this here: http://forums.activiti.org/en/viewtopic.php?f=6&t=759&p=3305&hilit=formengine#p3305).

Your form-engine should use ScriptEngineManager instead of the Activiti ScriptEngines (take a look in the ScriptEngines.evaluate()), this way you can pass custom "bindings" including your services you want to expose. Offcourse, this way you bypass the activiti way of evaluating scripts, and just use JSR-223.

Hope this helps

Re: epressionManager property in ProcessEngineConfiguration

ptriller — Wed, 09 Feb 2011 13:23:18 GMT

Ok, thanks, maybe I'll look into that later,

for now I will just inject a serializable "context" java class into the process that wraps the service calls I need
with an execution listener. Not the most elegant solution, but it works.

Re: epressionManager property in ProcessEngineConfiguration

frederikherema1 — Wed, 09 Feb 2011 13:38:13 GMT

Smuggling services in using a Serializable? Sneaky

Re: epressionManager property in ProcessEngineConfiguration

tombaeyens — Thu, 10 Feb 2011 12:49:27 GMT

I will be revisiting this and your request should be tackled in this release.