Data

Table of Contents

• Instance Data
• Item Data
• Data Scope
• Query on Data
• input/Output Data

Instance Data

Instance Data can be manipulated in several ways:

As Input to Engine calls

    const input={ model: 'Thunderbird', needsRepairs: false, needsCleaning: false };
    response = await engine.invoke({items: { id: itemId } }, input );

Expressions

keeping in mind that the bpmn definition defines conditional flow as such:

    <bpmn:sequenceFlow id="flow_gw1_clean" sourceRef="gateway_1" targetRef="task_clean">
      <bpmn:conditionExpression xsi:type="bpmn:tExpression"><![CDATA[
      (this.needsCleaning=="Yes")
      ]]></bpmn:conditionExpression>
    </bpmn:sequenceFlow>

Part of Script and Service Task

    <bpmn2:scriptTask id="task_reminder" name="Issue Reminder">
      <bpmn2:incoming>SequenceFlow_1h10gv4</bpmn2:incoming>
      <bpmn2:outgoing>SequenceFlow_0cokf0m</bpmn2:outgoing>
      <bpmn2:script><![CDATA[
            let data = this.token.data;
            console.log("sending a reminder scirpt");
            console.log(data);
            
            if (typeof data.reminderCounter === 'undefined') {
              data['reminderCounter']=0;
            }            
            
            data['reminderCounter']=data['reminderCounter']+1;
            this.token.log('testing from the inside: ');
      ]]></bpmn2:script>
    </bpmn2:scriptTask>

AppDelegate

Similar to Script and Service AppDelegate can manupilate Instance data.

Script Extensions

Script Extensions are supported in release 1.1 and later, allowing you to add a script to any node.

In this example we are adding a script to bpmn:startEvent

    <bpmn:startEvent id="StartEvent_1ohx91b">
      <bpmn:extensionElements>
        <camunda:script event="start"><![CDATA[
        console.log("This is the start event");
          this.applyInput({records:[1,2,3]});
          console.log(this.data);
          console.log("This is the start event");]]></camunda:script>
      </bpmn:extensionElements>
      <bpmn:outgoing>Flow_18xinq3</bpmn:outgoing>
    </bpmn:startEvent>
    

Item Data

In Release 1.3.22 added item.vars to store any variables related to the item as follows

Setting item.vars

You can set item.vars Inside your service logic :

  async service1(input, context) {
  ...
  item.vars= input;
 ...
}

or by having an event-listener such as:

MongoDB:

As a result MongoDB stores item.vars

Using findItems:

            query = { "data.caseId": caseId, "items.vars.param1": 'value1' };
            items = await server.dataStore.findItems(query);
            console.log('items count',items);

Data Scope

The entire execution will have one data scope object, shared among all nodes, except the following will have own item part of the data object

• SubProcess
• and Loops (Multi-instances)

However, for SubProcess and Loop elements a seperate scope

Query on Data

You can use Instance data as part of your query for Instances or Items For Details on Query see Data Query

Input-Output Data

Input and output is used in the following scenarios:

• Subprocess (input/output)
• Service Tasks (input/output)
• Call Tasks (input/output)
• Throw Message/Signal (input)
• Catch Message/Signal (output)

Input/Output using Scripts

variable	description
item.data	refers to Instance Data or the token data for multi-instance tokens
item.input	refers to input variable into the called task/event
item.output	is the output of the called task/event

    <bpmn2:serviceTask id="Activity_00ticbc" name="Add 2 Using scripts" implementation="add" camunda:delegateExpression="add">
        <bpmn2:extensionElements>
        <camunda:executionListener event="start">
          <camunda:script scriptFormat="JavaScript">

            item.input.v1=33;
            item.input.v2=25;

          </camunda:script>
        </camunda:executionListener>
        <camunda:executionListener event="end">
          <camunda:script scriptFormat="JavaScript">
            
            item.data.result2= item.output + 100;

          </camunda:script>
        </camunda:executionListener>
      </bpmn2:extensionElements>

Input/Output using Camunda Extension of Input/Output Parameter

    <bpmn2:serviceTask id="Task_0xh2iwa" name="service1" implementation="service1">
      <bpmn2:extensionElements>
        <camunda:inputOutput>
          <camunda:inputParameter name="repeat">item.data.count</camunda:inputParameter>
          <camunda:outputParameter name="sequence">this.output.seq</camunda:outputParameter>
          <camunda:outputParameter name="returnText">'out text:'+this.output.text</camunda:outputParameter>
        </camunda:inputOutput>
      </bpmn2:extensionElements>

• parameter name is the name of variable
• value is a JavaScript expression

| Scenario | before call | caller Syntax| after call| |--|--|--|--|--| | Throw Msg| parameters.var1= '123';
output.var1 | throw(msg,parameters)| - | | Catch Msg| - | catch(msg,parameters)| data.var1= parameters.var1;| | Call Process| parameters.var1= '123'; | result=call(parameters)|data.var1= result.var1; | | Service Call | parameters.var1= '123'; | result=call(parameters)| data.var1= result.var1;| | Start Event| -| start(parameters)| data.var1= parameters.var1;
data.var1=input.var1;|

• Call specs:

    input:
        var1    ->  data.myVar1
        var2    ->  5
  
    output:
        scenario 1:
        result  ->  <nothing>
        scenario 2:
        result  ->  output.result
  

  on-entry: item.input.var1= 51;

  on-run: item.output=call fun(item.input)

  on-exit:

    scenario 1:
    data.result  = item.output;
    scenario 2:
    data.result  = item.output.result;
  

• Throw

  specs:

  output:

        caseId  ->  data.caseId
  

  on-entry:

     item.output.caseId= data.caseId;
  

  on-call:

    throw (signal,item.output)
  

• Catch

  specs: none

  start trigger:

        data.caseId=input.caseId;
  

• Start

  specs: none

  start trigger:

        data.caseId=input.caseId;