Features by Examples

Service Task

In Process definition (.bpmn file), use implementation attribute to define name of JavaScript/TypeScript Method to perform the Task:

    <bpmn:serviceTask id="serviceTask" name="Service Task" implementation="service1">
    ...
    </bpmn:serviceTask>

class AppServices {

    async service1(item,input) {
        seq++;
        await delay(3000 -(seq * 100) , 'test');
        item.log("SERVICE 1" + item.token.currentNode.id);
    }
}

Script Task

    <bpmn2:scriptTask id="Activity_06typtl" name="script" scriptFormat="JavaScript">
      <bpmn2:script>

       this.log('testing from &lt;testing&gt; the inside: '+data.loopKey);
      </bpmn2:script>
 ..
    </bpmn2:scriptTask>

Conditional Flow

  <bpmn:sequenceFlow>    

   <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression" language="JavaScript">
      (data.needsCleaning=="Yes")
   </bpmn:conditionExpression>
  ..

Form Input Fields

    <bpmn:userTask id="task_Buy" name="Buy">
      <bpmn:extensionElements>
        <camunda:formData>
          <camunda:formField id="needsRepairs" label="Repairs Required?" type="boolean" />
          <camunda:formField id="needsCleaning" label="Cleaning Required?" type="boolean" />
        </camunda:formData>
      </bpmn:extensionElements>
        ...
    </bpmn:userTask>    

Multiple Start Event

When a definition/process has multiple start node, you need to specify the start node when starting the process:

From the Web UI:

From API:

    response = await api.engine.start('invoice', 
        { reminderCounter: 0, caseId: caseId}, user, {startNodeId:'StartEvent_AP'});

Business Rule Task

BPMN-Server supports Business Rules implemented through DMN-Engine Business Rules can be defined as a Decision Table as in this example:

Decision Table is called through

    <bpmn2:businessRuleTask id="Task_1lcamp6" name="Vacation"  camunda:decisionRef="Vacation">

This will load the file 'Vacation.json' form the Processes folder as defined in configuration.js

Script Extensions

Scripts can be added to listen to two events: - Start before the Task is executed - End after the task is executed

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

    <bpmn2:extensionElements>
      <camunda:executionListener event="start">
        <camunda:script scriptFormat="JavaScript">

           console.log("This is the start event");
          data.records=[1,2,3];
          console.log(data);

        </camunda:script>
      </camunda:executionListener>
      <camunda:executionListener event="end">
        <camunda:script scriptFormat="JavaScript">

          console.log("This is the end event");          


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

Timer Event

    <bpmn:intermediateCatchEvent id="Event_timer">
      <bpmn:incoming>Flow_1sg7v2d</bpmn:incoming>
      <bpmn:outgoing>Flow_1nku8og</bpmn:outgoing>
      <bpmn:timerEventDefinition id="TimerEventDefinition_07xu06a">
        <bpmn:timeDuration xsi:type="bpmn:tExpression">PT2S</bpmn:timeDuration>
      </bpmn:timerEventDefinition>
    </bpmn:intermediateCatchEvent>

More on timers

Multi-instances Tasks

    <bpmn:scriptTask id="scriptTask" name="Script Task">
      <bpmn:incoming>Flow_159xzcz</bpmn:incoming>
      <bpmn:outgoing>Flow_0t7z2os</bpmn:outgoing>
      <bpmn:multiInstanceLoopCharacteristics isSequential="true" 
        camunda:collection="$(data.records)" />
      <bpmn:script><![CDATA[this.log('testing from the inside: '+data.loopKey);]]></bpmn:script>
    </bpmn:scriptTask>

For Multi-instance data handling see

Call Process

    <bpmn:callActivity id="activity_call" name="Call Task" calledElement="loop">
    ...
    </bpmn:callActivity>

In the above example 'loop' is the name of process to be called.

Throwing and Cathcing Messages

In this example, we will demonstrate how can two seperate processes communicate through "Messages"

1 Throw a message with data

When a process throw a message, bpmn-server checks if there is another process that can catch this message before dispatching it to AppDelegate.

    <bpmn2:intermediateThrowEvent id="throw_msg1" name="msg1">
      <bpmn2:messageEventDefinition id="messageEventDef1" messageRef="Msg1" />
      <bpmn2:extensionElements>
        <camunda:script event="start"><![CDATA[
        input.caseId= data.caseId;
        this.messageMatchingKey={'data.caseId': data.caseId };
        ]]></camunda:script>
      </bpmn2:extensionElements>
      ...
    </bpmn2:intermediateThrowEvent>

The above will through a messsage as follows: - Message Id: Msg1 - Message Output: caseId: <someValue>

2 Catch a message with data

The second process defines a start event to catch the message Msg1

    <bpmn2:startEvent id="StartEvent_1w66wpl" name="msg1">
      ...
      <bpmn2:messageEventDefinition id="messageEventDef4" messageRef="Msg1" />
    </bpmn2:startEvent>

Therefore, the system will create a new instance of the second process and assign the Message output data, namely, the caseId

3 Throw a message with data and a Key

In addition, the second process sends a confirmation message Confirm1 to the first process

    <bpmn2:intermediateThrowEvent id="throw_confirm1" name="confirm1">
      <bpmn2:messageEventDefinition id="messageEventDef2" messageRef="Confirm1" />
      <bpmn2:extensionElements>
        <camunda:script event="transformOutput"><![CDATA[

        this.output.confirm=true;
        this.context.messageMatchingKey={'data.caseId': this.token.data.caseId };

        ]]></camunda:script>
      </bpmn2:extensionElements>
        ...
    </bpmn2:intermediateThrowEvent>

Howerver, the challenge here is that make sure the message is sent to the specific instance, that is where the Matching key is used - Message Id: Confirm1 - Message Output: confirm: true - Message Matching Keyt: 'data.caseId': this.token.data.caseId

Input and Output Data Handling

this for details