Problem with retrieving properties of task form via REST API

mprzycho — Mon, 22 Aug 2011 06:47:47 GMT

I tried to get properties of task from via:http://localhost:8080/activiti-rest/service/form/{taskId}/propertiesI got following exception:WARNING: Exception or error caught in resourcejava.lang.NullPointerException at org.codehaus.jackson.node.ObjectNode.toString(ObjectNode.java:344) at

Re: Problem with retrieving properties of task form via REST API

frederikherema1 — Wed, 24 Aug 2011 08:07:22 GMT

What properties does the task exactly have (keys + values) you were trying to get?

Re: Problem with retrieving properties of task form via REST API

mprzycho — Wed, 24 Aug 2011 12:05:31 GMT

Process definition looks like that:



<?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="http://www.activiti.org/test">
  <process id="FormPropertiesTest" name="FormPropertiesTest">
    <documentation>Place documentation for the 'FormPropertiesTest' process here.</documentation>
    <startEvent id="startevent1" name="Start"></startEvent>
    <endEvent id="endevent1" name="End"></endEvent>
    <userTask id="usertask1" name="User Task" activiti:assignee="kermit" activiti:formKey="test.form">
      <extensionElements>


        <activiti:formProperty id="name" name="name" type="string" required="true" readable="true" writable="true"></activiti:formProperty>


      </extensionElements>
    </userTask>
    <sequenceFlow id="flow1" name="" sourceRef="startevent1" targetRef="usertask1"></sequenceFlow>
    <sequenceFlow id="flow2" name="" sourceRef="usertask1" targetRef="endevent1"></sequenceFlow>
  </process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_FormPropertiesTest">
    <bpmndi:BPMNPlane bpmnElement="FormPropertiesTest" id="BPMNPlane_FormPropertiesTest">
      <bpmndi:BPMNShape bpmnElement="startevent1" id="BPMNShape_startevent1">
        <omgdc:Bounds height="35" width="35" x="110" y="180"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="endevent1" id="BPMNShape_endevent1">
        <omgdc:Bounds height="35" width="35" x="380" y="200"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
        <omgdc:Bounds height="55" width="105" x="211" y="160"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="flow1" id="BPMNEdge_flow1">
        <omgdi:waypoint x="145" y="197"></omgdi:waypoint>
        <omgdi:waypoint x="263" y="215"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
        <omgdi:waypoint x="316" y="187"></omgdi:waypoint>
        <omgdi:waypoint x="380" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</definitions>

and the problem occurs. When I did couple of changes it worked:

I had to add script before this task and initialize variable, e.g. nameVar.
then I set expression of this task to "${nameVar}".
Now the proper value was returned.


<?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="http://www.activiti.org/test">
  <process id="FormPropertiesTest" name="FormPropertiesTest">
    <documentation>Place documentation for the 'FormPropertiesTest' process here.</documentation>
    <startEvent id="startevent1" name="Start"></startEvent>
    <endEvent id="endevent1" name="End"></endEvent>
    <userTask id="usertask1" name="User Task" activiti:assignee="kermit" activiti:formKey="test.form">
      <extensionElements>

        <activiti:formProperty id="name" name="name" type="string" expression="${nameVar}" required="true" readable="true" writable="true"></activiti:formProperty>

      </extensionElements>
    </userTask>
    <sequenceFlow id="flow1" name="" sourceRef="startevent1" targetRef="scripttask1"></sequenceFlow>
    <sequenceFlow id="flow2" name="" sourceRef="usertask1" targetRef="endevent1"></sequenceFlow>
    <scriptTask id="scripttask1" name="Script Task" scriptFormat="javascript">

      <script><![CDATA[execution.setVariable("nameVar", "")]]></script>

    </scriptTask>
    <sequenceFlow id="flow3" name="" sourceRef="scripttask1" targetRef="usertask1"></sequenceFlow>
  </process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_FormPropertiesTest">
    <bpmndi:BPMNPlane bpmnElement="FormPropertiesTest" id="BPMNPlane_FormPropertiesTest">
      <bpmndi:BPMNShape bpmnElement="startevent1" id="BPMNShape_startevent1">
        <omgdc:Bounds height="35" width="35" x="110" y="180"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="endevent1" id="BPMNShape_endevent1">
        <omgdc:Bounds height="35" width="35" x="380" y="200"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
        <omgdc:Bounds height="55" width="105" x="211" y="160"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="scripttask1" id="BPMNShape_scripttask1">
        <omgdc:Bounds height="55" width="105" x="190" y="260"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="flow1" id="BPMNEdge_flow1">
        <omgdi:waypoint x="127" y="215"></omgdi:waypoint>
        <omgdi:waypoint x="190" y="287"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
        <omgdi:waypoint x="316" y="187"></omgdi:waypoint>
        <omgdi:waypoint x="380" y="217"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow3" id="BPMNEdge_flow3">
        <omgdi:waypoint x="295" y="287"></omgdi:waypoint>
        <omgdi:waypoint x="263" y="215"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</definitions>

Is it neccessary to both initialize variables (this way or by passing it through start step) and declare task formProperties to get this service done?

Re: Problem with retrieving properties of task form via REST API

frederikherema1 — Wed, 24 Aug 2011 12:11:50 GMT

If you set the variable attr readable to "true", the variable SHOULD exist when the task props are fetched, it expect a variable with that name…

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