Cannot create diagram elements using Fluent Api

Camunda 7 Topics Discussion & Questions
1

I am trying to get familiar with Fluent API and using 7.7.0-alpha1 maven library. I took an example from the documents and created following class in java :

public class DataLineageImplHelper {

public static void createXml() {
    //easyExample();
    easyExampleWithDetails();
    //thirdExample();
    First();
}

public static  <T extends BpmnModelElementInstance> T createElement(BpmnModelInstance modelInstance,
                                                               BpmnModelElementInstance parentElement, String id, Class<T> elementClass) {
    T element = modelInstance.newInstance(elementClass);
    element.setAttributeValue("id", id, true);
    parentElement.addChildElement(element);
    return element;
}

public static SequenceFlow createSequenceFlow(BpmnModelInstance modelInstance, Process process, FlowNode from, FlowNode to) {
    String identifier = from.getId() + "-" + to.getId();
    SequenceFlow sequenceFlow = createElement(modelInstance, process, identifier, SequenceFlow.class);
    process.addChildElement(sequenceFlow);
    sequenceFlow.setSource(from);
    from.getOutgoing().add(sequenceFlow);
    sequenceFlow.setTarget(to);
    to.getIncoming().add(sequenceFlow);
    return sequenceFlow;
}

public static void easyExampleWithDetails() {
    // create an empty model
    BpmnModelInstance modelInstance =  Bpmn.createEmptyModel();
    Definitions definitions = modelInstance.newInstance(Definitions.class);
    definitions.setTargetNamespace("http://camunda.org/examples");
    modelInstance.setDefinitions(definitions);

    // create the process
    Process process = createElement(modelInstance, definitions, "process-with-one-task", Process.class);

    // create start event, user task and end event
    StartEvent startEvent = createElement(modelInstance, process, "start", StartEvent.class);
    UserTask task1 = createElement(modelInstance, process, "task1", UserTask.class);
    task1.setName("Process 1");
    EndEvent endEvent = createElement(modelInstance, process, "end", EndEvent.class);

    // create the connections between the elements
    createSequenceFlow(modelInstance, process, startEvent, task1);
    createSequenceFlow(modelInstance, process, task1, endEvent);

    Bpmn.validateModel(modelInstance);
    String xmlString = Bpmn.convertToString(modelInstance);
    System.out.println(xmlString);
    File file = new File("Desktop/BPMN/bpmn files/Second.bpmn");
    Bpmn.writeModelToFile(file, modelInstance);
}

}

This generates a .bpmn file without any Diagram elements. The output looks like this :

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<definitions id="definitions_0a80c816-2df6-4658-9739-7d600837fa81" targetNamespace="http://camunda.org/examples" xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL">
  <process id="process-with-one-task">
    <startEvent id="start">
      <outgoing>start-task1</outgoing>
    </startEvent>
    <userTask id="task1" name="Process 1">
      <incoming>start-task1</incoming>
      <outgoing>task1-end</outgoing>
    </userTask>
    <endEvent id="end">
      <incoming>task1-end</incoming>
    </endEvent>
    <sequenceFlow id="start-task1" sourceRef="start" targetRef="task1"/>
    <sequenceFlow id="task1-end" sourceRef="task1" targetRef="end"/>
  </process>
</definitions>

Can someone please help me what is the missing piece in the code to generate diagram elements?

2

Diagram Interchange data only gets generated when you use the fluent builder. See https://github.com/camunda/camunda-bpm-examples/tree/master/bpmn-model-api/generate-process-fluent-api for an example. Also, I recommend you switch from 7.7.0-alpha1 to 7.7.0 for additional features and bug fixes.

Cheers,
Thorben

3

Hello,
Maybe you need to add BpmnEdge and Waypoint in createSequenceFlow.

Example;

UserTask task = createElement(modelInstance, process, “task”, “GeneralUserTaskModel”, UserTask.class, plane, 50d, 50d, 75d, 100d, true);

public SequenceFlow createSequenceFlow(BpmnModelInstance modelInstance, Process process, FlowNode from, FlowNode to, BpmnPlane plane,
Integer… waypoints) {
String identifier = from.getId() + “-” + to.getId();
SequenceFlow sequenceFlow = modelInstance.newInstance(SequenceFlow.class);
sequenceFlow.setAttributeValue(“id”, identifier, true);
process.addChildElement(sequenceFlow);
sequenceFlow.setSource(from);
from.getOutgoing().add(sequenceFlow);
sequenceFlow.setTarget(to);
to.getIncoming().add(sequenceFlow);

BpmnEdge bpmnEdge = modelInstance.newInstance(BpmnEdge.class);
bpmnEdge.setBpmnElement(sequenceFlow);
for (int i = 0; i < waypoints.length / 2; i++) {
double waypointX = waypoints[i*2];
double waypointY = waypoints[i*2+1];
Waypoint wp = modelInstance.newInstance(Waypoint.class);
wp.setX(waypointX);
wp.setY(waypointY);
bpmnEdge.addChildElement(wp);
}
plane.addChildElement(bpmnEdge);

return sequenceFlow;
}

4