topic How to create a variable JavaServiceTask ? in Alfresco Archive

How to create a variable JavaServiceTask ?

vire7777 — Tue, 20 Nov 2012 16:18:02 GMT

Hi people I'm creating a new workflow with our cool activiti stuff and wondering if that's possible to create a javaServiceTask with a variable activiti class to be used in multiple workflow instance with different goals. For example, the first workflow instance would initialize "myVariable" to ca

Re: How to create a variable JavaServiceTask ?

ronald_van_kuij — Tue, 20 Nov 2012 19:27:46 GMT

You can try if it works when turning of validation. Might be that it is ' just' a problem in the xsd

Re: How to create a variable JavaServiceTask ?

vire7777 — Wed, 21 Nov 2012 09:45:35 GMT

Nope ! it told me :

GRAVE: Error while closing command context
org.activiti.engine.ActivitiException: couldn't instantiate class ${testVariable}

Well maybe that's impossible

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Wed, 21 Nov 2012 09:50:04 GMT


activiti:class="${testVariable}"

activiti:class should be a string literal, containing a class-name… If you want to have a dynamic JavaDelegate, take a look at activiti:expression en activiti:delegateExpression in the user guide.

Re: How to create a variable JavaServiceTask ?

vire7777 — Wed, 21 Nov 2012 11:02:58 GMT

I ve seen them but don't know how to use them (maybe i don't really understand)… It seems they don't call for java classes…

Could you just give me an example of a very simple workflow with two javaServiceTask ?
- The first javaServiceTask would call a class with activiti:class where you create a process variable "toto" which contains "org.activiti.MyClass". Like :

public class SetterTest implements JavaDelegate {

 private static final String VARIABLE_NAME = "toto";

 public void execute(DelegateExecution execution) {
  String var = "org.activiti.MyClass";
  execution.setVariable(VARIABLE_NAME, var);
 }
}

- And the second javaServiceTask would call the toto variable class.

If you can do it, you would resolve my problem because i'm really out of ideas right now

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Wed, 21 Nov 2012 11:39:46 GMT

What are you trying to do? Add a POJO as a variable to your process, and call it later on?

In that case, add a POJO instance as a process-variable (make sure it implements Serializable) instead of the classname. Afterwards, use activiti:delegateExpression="${myVariable.doStuff()}" (supposing the POJO has a doStuff method).

Please note, using a serializable as variable works, but not sure what your use case would be…

Re: How to create a variable JavaServiceTask ?

vire7777 — Wed, 21 Nov 2012 12:17:46 GMT

Woooowww, so cool :=)
It works as it enters my code but after executing it, i have an error !

GRAVE: Error while closing command context
org.activiti.engine.ActivitiException: Delegate expression ${myVariable.execute()} did not resolve to an implementation of interface org.activiti.engine.impl.pvm.delegate.ActivityBehavior nor interface org.activiti.engine.delegate.JavaDelegate

That s strange because my class MyClass.java which is stored in myVariable implements serializable (as you told me) and JavaDelegate…
Where is the problem so ?

One other question : If i want to pass process or task parameters to my method doStuff(), can i do it by creating them in the task or process and just call : activiti:delegateExpression="${myVariable.doStuff(param1, param2, …)}" or do i have to do something different ?

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Wed, 21 Nov 2012 12:47:57 GMT

don't do the ${myVariable.execute()}, just point to the delegate: ${myVariable} and it will work…

Re: How to create a variable JavaServiceTask ?

vire7777 — Wed, 21 Nov 2012 12:55:16 GMT

Already done and i have the same error message. In addition, it doesn't enter the method "execute" however when i wrote : ${myVariable.test()}, it enters the method "test".

public class ManagerTest implements Serializable, JavaDelegate {

 /**
  * 
  */
 private static final long serialVersionUID = 1L;

 @Override
 public void execute(DelegateExecution arg0) throws Exception {
  int a = 1;
 }

        public void test() throws Exception {
  int a = 1;
 }
}

I m really sorry for all that work i m giving to you, i really feel as a newb :'(

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Thu, 22 Nov 2012 08:55:19 GMT

Please consult the user guide regarding JavaDelegates. If you're pointing to a JavaDelegate instance, use activiti:delegateExpression="${myVar}". When using alternative method, use activiti:expression="${myVar.test()}"

Re: How to create a variable JavaServiceTask ?

vire7777 — Thu, 22 Nov 2012 10:23:47 GMT

I m sorry guys but nothing explains how to solve my problem in the user guide as there is just a really little sentence for "activiti:delegateExpression"

In addition, as i told, when i use :
activiti:delegateExpression="${myVar}"

It doesn't enter my method

@Override
   public void execute(DelegateExecution arg0) throws Exception {
      int a = 1;
   }

But when i use :
activiti:delegateExpression="${myVar.execute()}"

It enters my other method :

@Override
   public void execute() throws Exception {
      int a = 2;
   }

In all cases i have the error message :

GRAVE: Error while closing command context
org.activiti.engine.ActivitiException: Delegate expression ${myVar.execute()} (or ${myVar} for the first example) did not resolve to an implementation of interface org.activiti.engine.impl.pvm.delegate.ActivityBehavior nor interface org.activiti.engine.delegate.JavaDelegate

Then, i ll try with "activiti:expression" but really i would prefer doing it with the delegateExpression…

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Thu, 22 Nov 2012 12:09:49 GMT

A delegateExpression can be used when the expression resolves to an instance of a JavaDelegate-implementing class. Nothing more, nothing less. If it doesn't work, it means there is something wrong with your class. What "JavaDelegate" are you implementing?

Can you post you java-class and the bpmn20.xml?

Re: How to create a variable JavaServiceTask ?

vire7777 — Thu, 22 Nov 2012 13:56:27 GMT

So here's my code :

Here's the Bpmn20 :

<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:activiti="http://activiti.org/bpmn" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:smileysurprised:mgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:smileysurprised:mgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="Examples">
  <process id="MyTest" name="MyTest">
    <startEvent id="theStart" name="Start"></startEvent>
    <serviceTask id="javaService" name="Java service invocation" activiti:class="org.activiti.examples.bpmn.test.manager2.SetterTest">
      <extensionElements>
        <activiti:field name="text">
          <activiti:string>Success</activiti:string>
        </activiti:field>
      </extensionElements>
    </serviceTask>
    <serviceTask id="javaService2" name="Java service invocation" activiti:delegateExpression="${testVariable}"></serviceTask>
    <userTask id="usertask1" name="User Task" activiti:candidateGroups="user"></userTask>
    <endEvent id="theEnd" name="End"></endEvent>
    <sequenceFlow id="flow1" name="" sourceRef="theStart" targetRef="javaService"></sequenceFlow>
    <sequenceFlow id="flow2" name="" sourceRef="javaService" targetRef="javaService2"></sequenceFlow>
    <sequenceFlow id="flow4" name="" sourceRef="usertask1" targetRef="theEnd"></sequenceFlow>
    <sequenceFlow id="flow5" name="" sourceRef="javaService2" targetRef="usertask1"></sequenceFlow>
  </process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_MyTest">
    <bpmndi:BPMNPlane bpmnElement="MyTest" id="BPMNPlane_MyTest">
      <bpmndi:BPMNShape bpmnElement="theStart" id="BPMNShape_theStart">
        <omgdc:Bounds height="35" width="35" x="30" y="200"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="javaService" id="BPMNShape_javaService">
        <omgdc:Bounds height="55" width="105" x="105" y="190"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="javaService2" id="BPMNShape_javaService2">
        <omgdc:Bounds height="55" width="105" x="250" y="190"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
        <omgdc:Bounds height="55" width="105" x="395" y="190"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="theEnd" id="BPMNShape_theEnd">
        <omgdc:Bounds height="35" width="35" x="540" y="200"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="flow1" id="BPMNEdge_flow1">
        <omgdi:waypoint x="65" y="217"></omgdi:waypoint>
        <omgdi:waypoint x="105" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
        <omgdi:waypoint x="210" y="217"></omgdi:waypoint>
        <omgdi:waypoint x="250" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow4" id="BPMNEdge_flow4">
        <omgdi:waypoint x="500" y="217"></omgdi:waypoint>
        <omgdi:waypoint x="540" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow5" id="BPMNEdge_flow5">
        <omgdi:waypoint x="355" y="217"></omgdi:waypoint>
        <omgdi:waypoint x="395" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</definitions>

here's the first class :


package org.activiti.examples.bpmn.test.manager2;

import org.activiti.engine.delegate.DelegateExecution;
import org.activiti.engine.delegate.Expression;
import org.activiti.engine.delegate.JavaDelegate;

public class SetterTest implements JavaDelegate {

 private static final String VARIABLE_NAME = "testVariable";
 private Expression text;

 public void execute(DelegateExecution execution) {
  String var = (String) text.getValue(execution);

  if ("Success".equals(var)) {
   ManagerTest manager = new ManagerTest();
   execution.setVariable(VARIABLE_NAME, manager);
  }
 }

}

Here's the second class :


package org.activiti.examples.bpmn.test.manager2;

import java.io.Serializable;

import org.activiti.engine.delegate.DelegateExecution;
import org.activiti.engine.delegate.JavaDelegate;

public class ManagerTest implements Serializable, JavaDelegate {

 private static final long serialVersionUID = 1L;

 @Override
 public void execute(DelegateExecution arg0) throws Exception {
  int a = 1;
 }
}

All i want is : going to my second class and set "a" to 1

Re: How to create a variable JavaServiceTask ?

vire7777 — Thu, 22 Nov 2012 14:10:05 GMT

Ok ! you can clause this thread !
I don't know why but now it works just fine although i haven't done a thing…
Something strange happens sometimes in computers that i really can't understand

Anyway, i don't have the problem now.
So thanks a lot for all

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Thu, 22 Nov 2012 14:15:50 GMT

Glad it worked out for you…

Re: How to create a variable JavaServiceTask ?

vire7777 — Thu, 22 Nov 2012 14:20:09 GMT

just a last question (promise, this one would be quick) :

Every time i launch my activiti-explorer project with tomcat, it tries to re-create the database tables.
Then i have to delete them each time else i have many errors like "the table xxxx already exists"
How to stop it ?

Re: How to create a variable JavaServiceTask ?

frederikherema1 — Thu, 22 Nov 2012 14:34:06 GMT

Please read the user guide, sections http://activiti.org/userguide/index.html#databaseUpgrade, http://activiti.org/userguide/index.html#configurationRoot and http://activiti.org/userguide/index.html#databaseConfiguration where you can find the right properties to fiddle with to prevent this…

Re: How to create a variable JavaServiceTask ?

vire7777 — Thu, 22 Nov 2012 14:39:39 GMT

^^
Thanks a lot for all !
I have no other question for the moment