Unable to create edges

[hsd-dev]

I am updating the java-emf-theia example to be able to add transitions. I have updated the EMFNotationGModelFactory as follows

public class MyGLSPGModelFactory extends EMFNotationGModelFactory {

	@Override
	protected void fillRootElement(EObject semanticModel, Diagram notationModel, GModelRoot newRoot) {
		// TODO Auto-generated method stub
		TaskList taskList = TaskList.class.cast(semanticModel);
		GGraph graph = GGraph.class.cast(newRoot);

		if (notationModel.getSemanticElement() != null
				&& notationModel.getSemanticElement().getResolvedSemanticElement() != null) {
			for (Iterator<Task> iterator = taskList.getTasks().iterator(); iterator.hasNext();) {
				Task task = (Task) iterator.next();
				GNodeBuilder builder = new GNodeBuilder(DefaultTypes.NODE).size(60, 20)
						.id(idGenerator.getOrCreateId(task)).addCssClass("minimal-node")
						.add(new GLabelBuilder(DefaultTypes.LABEL).text(task.getName()).build());

				applyShapeData(task, builder);
				graph.getChildren().add(builder.build());
			}

			for (Iterator<Transition> iterator = taskList.getTransitions().iterator(); iterator.hasNext();) {
				Transition transition = (Transition) iterator.next();
				String sourceId = transition.getSource().getId();
				String targetId = transition.getTarget().getId();

				GModelElement sourceNode = findGNodeById(graph.getChildren(), sourceId);
				GModelElement targetNode = findGNodeById(graph.getChildren(), targetId);

				GEdgeBuilder builder = new GEdgeBuilder(DefaultTypes.EDGE).source(sourceNode).target(targetNode)
						.id(idGenerator.getOrCreateId(transition));
				applyEdgeData(transition, builder);
				graph.getChildren().add(builder.build());
			}
		}
	}

	protected GModelElement findGNodeById(EList<GModelElement> eList, String elementId) {
		return eList.stream().filter(node -> elementId.equals(node.getId())).findFirst().orElse(null);
	}
}

and created a AbstractEMFCreateEdgeOperationHandler as follows

ublic class MyGLSPCreateEdgeHandler extends AbstractEMFCreateEdgeOperationHandler {

	@Inject
	protected EMFNotationModelState modelState;

	@Inject
	protected EMFIdGenerator idGenerator;

	public MyGLSPCreateEdgeHandler() {
		super(DefaultTypes.EDGE);
	}

	@Override
	public Optional<Command> createCommand(CreateEdgeOperation operation) {
		// TODO Auto-generated method stub

		TaskList taskList = modelState.getSemanticModel(TaskList.class).orElseThrow();
		Diagram diagram = modelState.getNotationModel();
		EditingDomain editingDomain = modelState.getEditingDomain();

		String sourceId = operation.getSourceElementId();
		String targetId = operation.getTargetElementId();

		Task sourceTask = findTaskById(taskList.getTasks(), sourceId);
		Task targetTask = findTaskById(taskList.getTasks(), targetId);

		Transition newTransition = createTransition(sourceTask, targetTask);
		Command transitionCommand = AddCommand.create(editingDomain, taskList,
				ModelPackage.Literals.TASK_LIST__TRANSITIONS, newTransition);

		Edge newEdge = createEdge(idGenerator.getOrCreateId(newTransition));
		Command edgeCommand = AddCommand.create(editingDomain, diagram, NotationPackage.Literals.DIAGRAM__ELEMENTS,
				newEdge);

		CompoundCommand compoundCommand = new CompoundCommand();
		compoundCommand.append(transitionCommand);
		compoundCommand.append(edgeCommand);
		return Optional.of(compoundCommand);
	}

	@Override
	public String getLabel() {
		return "Edge";
	}

	protected Task findTaskById(EList<Task> tasks, String elementId) {
		return tasks.stream().filter(task -> elementId.equals(task.getId())).findFirst().orElse(null);
	}

	protected NotationElement findGNodeById(EList<NotationElement> eList, String elementId) {
		return eList.stream().filter(node -> elementId.equals(node.getSemanticElement().getElementId())).findFirst()
				.orElse(null);
	}

	protected void setInitialName(final Transition transition) {
		Function<Integer, String> nameProvider = i -> "New" + transition.eClass().getName() + i;
		int edgeCounter = modelState.getIndex().getCounter(GraphPackage.Literals.GEDGE, nameProvider);
		transition.setName(nameProvider.apply(edgeCounter));
	}

	protected Transition createTransition(Task sourceTask, Task targetTask) {
		Transition newTransition = ModelFactory.eINSTANCE.createTransition();
		newTransition.setId(UUID.randomUUID().toString());
		setInitialName(newTransition);
		newTransition.setSource(sourceTask);
		newTransition.setTarget(targetTask);
		return newTransition;
	}

	protected Edge createEdge(final String elementId) {
		Edge newEdge = NotationFactory.eINSTANCE.createEdge();
		SemanticElementReference reference = NotationFactory.eINSTANCE.createSemanticElementReference();
		reference.setElementId(elementId);
		newEdge.setSemanticElement(reference);
		return newEdge;
	}
}

But as soon as I click on the target node in the theia ide, I get the following error

[GLSP-Server] Could not process message:ActionMessage [action=createEdge, clientId=my-glsp-diagram:file:///home/ipa-hsd/projects/kogrob2/urdf/glsp_tests/glsp-examples/project-templates/java-emf-theia/glsp-client/workspace/example.tasklist]
Could not initialize class org.eclipse.emf.edit.command.AddCommand
java.lang.NoClassDefFoundError: Could not initialize class org.eclipse.emf.edit.command.AddCommand
	at org.eclipse.glsp.example.handler.MyGLSPCreateEdgeHandler.createCommand(MyGLSPCreateEdgeHandler.java:59)
	at org.eclipse.glsp.example.handler.MyGLSPCreateEdgeHandler.createCommand(MyGLSPCreateEdgeHandler.java:32)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:38)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.lambda$getCommand$0(EMFOperationHandler.java:79)
	at java.base/java.util.Optional.flatMap(Optional.java:294)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:79)
	at org.eclipse.glsp.server.emf.EMFOperationActionHandler.executeOperation(EMFOperationActionHandler.java:35)
	at org.eclipse.glsp.server.operations.OperationActionHandler.executeAction(OperationActionHandler.java:53)
	at org.eclipse.glsp.server.operations.OperationActionHandler.executeAction(OperationActionHandler.java:31)
	at org.eclipse.glsp.server.actions.AbstractActionHandler.execute(AbstractActionHandler.java:53)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.runAction(DefaultActionDispatcher.java:193)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.handleAction(DefaultActionDispatcher.java:172)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.handleNextAction(DefaultActionDispatcher.java:159)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.runThread(DefaultActionDispatcher.java:145)
	at java.base/java.lang.Thread.run(Thread.java:829)

In fact I get a similar error even for creating nodes, even though the implementation of AbstractEMFCreateNodeOperationHandler is the same as that from the example. My intuition is that I am doing something wrong here

			for (Iterator<Transition> iterator = taskList.getTransitions().iterator(); iterator.hasNext();) {
				Transition transition = (Transition) iterator.next();
				String sourceId = transition.getSource().getId();
				String targetId = transition.getTarget().getId();

				GModelElement sourceNode = findGNodeById(graph.getChildren(), sourceId);
				GModelElement targetNode = findGNodeById(graph.getChildren(), targetId);

				GEdgeBuilder builder = new GEdgeBuilder(DefaultTypes.EDGE).source(sourceNode).target(targetNode)
						.id(idGenerator.getOrCreateId(transition));
				applyEdgeData(transition, builder);
				graph.getChildren().add(builder.build());
			}

[planger]

@ndoschek or @martin-fleck-at, can you please take a look? Thanks!

[hsd-dev]

Not sure if it is related, but when I first start the server, and when I move an existing node in Theia, I get an error:

java.lang.ExceptionInInitializerError
	at org.eclipse.glsp.server.emf.notation.EMFChangeBoundsOperationHandler.updateShape(EMFChangeBoundsOperationHandler.java:61)
	at org.eclipse.glsp.server.emf.notation.EMFChangeBoundsOperationHandler.lambda$createCommand$0(EMFChangeBoundsOperationHandler.java:50)
	at java.base/java.util.Optional.map(Optional.java:265)
	at org.eclipse.glsp.server.emf.notation.EMFChangeBoundsOperationHandler.createCommand(EMFChangeBoundsOperationHandler.java:50)
	at org.eclipse.glsp.server.emf.notation.EMFChangeBoundsOperationHandler.createCommand(EMFChangeBoundsOperationHandler.java:38)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:38)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.lambda$getCommand$0(EMFOperationHandler.java:79)
	at java.base/java.util.Optional.flatMap(Optional.java:294)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:79)
	at org.eclipse.glsp.server.emf.EMFCompoundOperationHandler.getNestedCommand(EMFCompoundOperationHandler.java:47)
	at org.eclipse.glsp.server.emf.EMFCompoundOperationHandler.lambda$createCommand$0(EMFCompoundOperationHandler.java:40)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.eclipse.glsp.server.emf.EMFCompoundOperationHandler.createCommand(EMFCompoundOperationHandler.java:40)
	at org.eclipse.glsp.server.emf.EMFCompoundOperationHandler.createCommand(EMFCompoundOperationHandler.java:31)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:38)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.lambda$getCommand$0(EMFOperationHandler.java:79)
	at java.base/java.util.Optional.flatMap(Optional.java:294)
	at org.eclipse.glsp.server.emf.EMFOperationHandler.getCommand(EMFOperationHandler.java:79)
	at org.eclipse.glsp.server.emf.EMFOperationActionHandler.executeOperation(EMFOperationActionHandler.java:35)
	at org.eclipse.glsp.server.operations.OperationActionHandler.executeAction(OperationActionHandler.java:53)
	at org.eclipse.glsp.server.operations.OperationActionHandler.executeAction(OperationActionHandler.java:31)
	at org.eclipse.glsp.server.actions.AbstractActionHandler.execute(AbstractActionHandler.java:53)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.runAction(DefaultActionDispatcher.java:193)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.handleAction(DefaultActionDispatcher.java:172)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.handleNextAction(DefaultActionDispatcher.java:159)
	at org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher.runThread(DefaultActionDispatcher.java:145)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.util.MissingResourceException: The string resource '_UI_SetCommand_label' could not be located
	at org.eclipse.emf.common.util.DelegatingResourceLocator.delegatedGetString(DelegatingResourceLocator.java:578)
	at org.eclipse.emf.common.util.DelegatingResourceLocator.getString(DelegatingResourceLocator.java:450)
	at org.eclipse.emf.common.util.DelegatingResourceLocator.getString(DelegatingResourceLocator.java:424)
	at org.eclipse.emf.edit.command.SetCommand.<clinit>(SetCommand.java:368)
	... 27 more

This does not happen when I use the existing java-emf-theia example.

[ndoschek]

Hi @ipa-hsd!

Thanks for the provided code, it looks very good to me and I used that code and added it to the current java-emf-theia example to test the behavior. With registering the handler and adding the type hint for the edge, the example works great for me!
I added my state to a separate branch here: https://github.com/eclipse-glsp/glsp-examples/tree/java-emf-theia/transitions

Can you tell me if it works for you as well, and if not, which base did you use for your example and if you still get this errors?
Thanks!

[hsd-dev]

thanks @ndoschek for the response and happy to know that the code was usable :)

The code works if I modify the existing example java-emf-theia. But just to understand the concepts better, I started from the minimal example and updated the source model to EMF. The only thing I changed on the client side are these 2 lines

    diagramType: 'minimal-diagram',
    fileExtensions: ['.minimal']

to

    diagramType: 'tasklist-diagram',
    fileExtensions: ['.tasklist']

So I think I am missing something.

[ndoschek]

Hi again!
Basically, the tasklist example differs from the minimal example mainly that it contains an additional notation model (file extension .notation), which is repsonsible for the graphical information like positioning and sizing of diagram elements.
On the client side there should not be any more changes needed.
Also, the diagram type in the DiagramModule has to match on the server if you change it on the client side.

On the server you could take a look at the TaskListDiagramModule. It extends the EMFNotationDiagramModule which provides basic implementations for the use case with the additional notation model.
It adds for example the necessary EMFChangeBoundsOperationHandler if using the notation model and could explain that the moving does not work in your case (if you use the notation model too).

HTH in the meantime and let me know if there are still gaps I can help out with,
Nina

[hsd-dev]

Thanks again for your response! let me know if I have understood correctly about how the notation elements are mapped to the graphical nodes. In the CreateTaskNodeHandler, I see that the notation elements are created, which is also seen in .notation.

   protected Shape createShape(final String elementId, final Optional<GPoint> relativeLocation) {
      Shape newTask = NotationFactory.eINSTANCE.createShape();
      newTask.setPosition(relativeLocation.orElse(GraphUtil.point(0, 0)));
      newTask.setSize(GraphUtil.dimension(60, 25));
      SemanticElementReference reference = NotationFactory.eINSTANCE.createSemanticElementReference();
      reference.setElementId(elementId);
      newTask.setSemanticElement(reference);
      return newTask;
   }

While creating the GModel, this shape information is used here in applyShapeData

   protected GNode createTaskNode(final Task task) {
      GNodeBuilder taskNodeBuilder = new GNodeBuilder(TaskListModelTypes.TASK)
         .id(idGenerator.getOrCreateId(task))
         .addCssClass("tasklist-node")
         .add(new GLabelBuilder(DefaultTypes.LABEL).text(task.getName()).build())
         .layout(GConstants.Layout.HBOX, Map.of(GLayoutOptions.KEY_PADDING_LEFT, 5));

      applyShapeData(task, taskNodeBuilder);
      return taskNodeBuilder.build();
   }

Is that correct? In that case why an additional notation model is necessary? Can't the GModel itself store the graphical information?

[ndoschek]

Yes that is absolutely correct!
Basically, the generated GModel holds the information from both of these models.
It combines the semantic model information (e.g. the task name) and the notation model information (e.g. the task shape position).
In the minimal example, it is the case that all information is combined into one model data structure, you can compare it with this example model file.

However, there are use cases, where the two models (semantic and notation) should be separated (e.g. if there is an additional model representation via a tree editor where the notation information is irrelevant).

Please also take a look at our documentation, there are different project templates that try to meet different needs in regards to setting up a diagram editor.

[hsd-dev]

Thanks a lot Nina! This makes total sense now.