topic Re: Custom task listener and deleteCandidateGroup() in Alfresco Archive

Custom task listener and deleteCandidateGroup()

mandas — Wed, 03 Oct 2012 12:21:28 GMT

Hi,I 've implemented a task listener for the 'create' event in order to change the candidate groups according to runtime data (I 'm not using spring, so adding an expression to 'candidateGroups' I think it's not supported otherwise). Inside the task listener I do:delegateTask.deleteCandidateGroup("f

Re: Custom task listener and deleteCandidateGroup()

jbarrez — Thu, 04 Oct 2012 06:38:58 GMT

Could you post your whole Delegate class?

Re: Custom task listener and deleteCandidateGroup()

mandas — Thu, 04 Oct 2012 07:24:41 GMT

import org.activiti.engine.delegate.DelegateTask;
import org.activiti.engine.delegate.TaskListener;

public class MyTaskListener implements TaskListener {

@Override
public void notify(DelegateTask delegateTask) {
delegateTask.deleteCandidateGroup("foo");
delegateTask.addCandidateGroup("bar");
}

}

Re: Custom task listener and deleteCandidateGroup()

frederikherema1 — Thu, 04 Oct 2012 07:39:33 GMT

Is the candidate-group "foo" defined in the bpmn20.xml?

Re: Custom task listener and deleteCandidateGroup()

mandas — Thu, 04 Oct 2012 07:49:04 GMT

If you are referring to candidate group task property, yes. I debugged this class, and the IdentityLinkEntity of 'foo' was in delegateTask.getCandidates()

Re: Custom task listener and deleteCandidateGroup()

frederikherema1 — Thu, 04 Oct 2012 07:54:54 GMT

It would be great if you should create a simple unit-test highlighting this issue (see the sticky in the forum with good tops on how to do this).

Re: Custom task listener and deleteCandidateGroup()

michj_74 — Thu, 11 Jul 2013 09:08:02 GMT

I'm running into the same issue now. Has this been resolved?

Thanks,Mike

Re: Custom task listener and deleteCandidateGroup()

jbarrez — Fri, 12 Jul 2013 07:21:15 GMT

Are you still seeing the issue?
I think some work has been done in that area, but without a Jira issue in this post its hard to know if it has been fixed or not

Re: Custom task listener and deleteCandidateGroup()

michj_74 — Fri, 12 Jul 2013 14:43:11 GMT

Hi,

yes, I'm still seeing it, I'm using activiti 5.12.1. The process definition is:

<code>
<?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" xmlnsmgdc="http://www.omg.org/spec/DD/20100524/DC" xmlnsmgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://www.activiti.org/test">
<collaboration id="Collaboration">
    <participant id="pool1" name="test-NPP-MAIN-NPP" processRef="process_pool15"></participant>
</collaboration>
<process id="process_pool15" name="test-NPP-MAIN-NPP-1" isExecutable="true">
    <laneSet id="laneSet_process_pool15">
      <lane id="groupid.pmnpp" name="groupid.pmnpp">
        <flowNodeRef>startevent1</flowNodeRef>
        <flowNodeRef>usertask1</flowNodeRef>
      </lane>
      <lane id="marketing" name="Marketing">
        <flowNodeRef>usertask3</flowNodeRef>
        <flowNodeRef>endevent1</flowNodeRef>
      </lane>
    </laneSet>
    <startEvent id="startevent1" name="Start"></startEvent>
    <userTask activiti:candidateGroups="groupid.pmnpp" id="usertask1" name="Create New Product" activiti:formKey="myFormKey"><extensionElements><activiti:taskListener event="create" class="com.mycompany.MyTaskAssigner" /></extensionElements></userTask>
    <sequenceFlow id="flow2" sourceRef="startevent1" targetRef="usertask1"></sequenceFlow>
    <sequenceFlow id="flow3" sourceRef="usertask1" targetRef="usertask3"></sequenceFlow>
    <userTask activiti:candidateGroups="groupid.pmnpp" id="usertask3" name="Verify Product" activiti:async="true" activiti:formKey="myFormKey"><extensionElements><activiti:taskListener event="create" class="com.mycompany.MyTaskAssigner" /></extensionElements></userTask>
    <endEvent id="endevent1" name="End"></endEvent>
    <sequenceFlow id="flow4" sourceRef="usertask3" targetRef="endevent1"></sequenceFlow>
</process>
<bpmndi:BPMNDiagram id="BPMNDiagram_Collaboration">
    <bpmndi:BPMNPlane bpmnElement="Collaboration" id="BPMNPlane_Collaboration">
      <bpmndi:BPMNShape bpmnElement="pool1" id="BPMNShape_pool1">
        <omgdc:Bounds height="520.0" width="500.0" x="110.0" y="70.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="groupid.pmnpp" id="BPMNShape_groupid.pmnpp">
        <omgdc:Bounds height="260.0" width="480.0" x="130.0" y="70.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="marketing" id="BPMNShape_marketing">
        <omgdc:Bounds height="260.0" width="480.0" x="130.0" y="330.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="startevent1" id="BPMNShape_startevent1">
        <omgdc:Bounds height="35.0" width="35.0" x="180.0" y="198.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
        <omgdc:Bounds height="71.0" width="145.0" x="320.0" y="180.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask3" id="BPMNShape_usertask3">
        <omgdc:Bounds height="55.0" width="105.0" x="310.0" y="390.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="endevent1" id="BPMNShape_endevent1">
        <omgdc:Bounds height="35.0" width="35.0" x="470.0" y="400.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
        <omgdi:waypoint x="215.0" y="215.0"></omgdi:waypoint>
        <omgdi:waypoint x="320.0" y="215.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow3" id="BPMNEdge_flow3">
        <omgdi:waypoint x="392.0" y="251.0"></omgdi:waypoint>
        <omgdi:waypoint x="362.0" y="390.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow4" id="BPMNEdge_flow4">
        <omgdi:waypoint x="415.0" y="417.0"></omgdi:waypoint>
        <omgdi:waypoint x="470.0" y="417.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
</bpmndi:BPMNDiagram>
</definitions>
</code>

The task assigner code is:

<code>
package com.mycompany;

import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;

import org.activiti.engine.delegate.DelegateTask;
import org.activiti.engine.delegate.TaskListener;
import org.activiti.engine.task.IdentityLink;

public class MyTaskAssigner implements TaskListener {

private static final long serialVersionUID = 1L;

@Override
public void notify(DelegateTask delegateTask) {
Set<IdentityLink> candidates = new HashSet<IdentityLink>();
candidates.addAll(delegateTask.getCandidates());
for (IdentityLink candidate : candidates) {
   if (candidate.getGroupId() != null) {
    if (candidate.getGroupId().contains(",")) {
     StringTokenizer t = new StringTokenizer(candidate.getGroupId(), ",");
     while (t.hasMoreTokens()) {
      delegateTask.deleteCandidateGroup(t.nextToken());
     }
    } else {
     delegateTask.deleteCandidateGroup(candidate.getGroupId());
    }
   }
}
}

}
</code>

When the process is executing I see that it jumps into the task assigner and delegateTask.deleteCandidateGroup() is being called but the assignment to the group remains unchanged. Am I doing something wrong?

Thanks,
Mike

Re: Custom task listener and deleteCandidateGroup()

frederikherema1 — Wed, 17 Jul 2013 10:32:03 GMT

The issue here is that the deleteIdentityLink() method will *try to* delete the identity-link in the database. Since the task isn't actually committed yet, the delete won't do anything. When the task-create call is done, they command-context will flush the pending entities that are created (process-instance, task and identity-links). Since the identity-links for candidate group are already queued for creation, they will be created.

This is an issue indeed and needs to be fixed. However, as a workaround (and perhaps a more valid approach for this kind of use case) I suggest using an expressions in the "activiti:candidateGroup" attribute, pointing to a bean in the context that decides what candidates are applicable for this task, at the time it's started. This will avoid having to use the listener and make use of the candidate-expression, where it was designed for. Eg. activiti:candidateGroups="${candidateChecker.getGroupsForTask(variableRelevantForDecision}".

Re: Custom task listener and deleteCandidateGroup()

michj_74 — Thu, 18 Jul 2013 14:20:48 GMT

Hi,

thanks for the info, I thought of something similar too. But anyway it's good to know that the issue is going to be fixed.

Cheers,
Mike

Re: Custom task listener and deleteCandidateGroup()

frederikherema1 — Fri, 19 Jul 2013 06:17:26 GMT

Please use https://jira.codehaus.org/browse/ACT-1749 to track progress on this…

Re: Custom task listener and deleteCandidateGroup()

xuhuisheng — Tue, 03 Sep 2013 12:42:00 GMT

create a pull request, and waiting for merge.
https://github.com/Activiti/Activiti/pull/106