How EdgeTypeHint works?

[glsp-bot]

Hello. I created simple diagram with 'Source', 'Translator' and 'Destination'. I created own edge type - 'TestEdge'. For this edge i created EdgeTypeHint with elementTypeId = 'TestEdge', sourceElementTypeIds = ['Source', 'Translator'], targetElementTypeIds = ['Translator', 'Destination']. But on the diagram i can create 'TestEdge' from destination to source.

I can return empty optional (but i get IllegalArgumentException 'Creation of connection failed for source: %s , target: %s') from edge create operation to prevent creation but then there is no graphical effects that such edge cannot be created. Do i use EdgeTypeHint right?

(Using 'next' version of glsp)

original thread by MoHcmp

[tortmayr]

At first glance it looks like you configured everything right. Did you also include the modelHintsModule on the client side? (https://github.com/eclipse-glsp/glsp-examples/blob/1100dc400a984202ca032e4ab6e9eb474dc67c41/minimal/client/minimal-glsp/src/di.config.ts#L68)

[glsp-bot]

[MoHcmp]

yes, i included modelHintsModule

[glsp-bot]

[MoHcmp]

what methods should i debug to check why edge can be connected?

[glsp-bot]

[MoHcmp]

I figured out whats wrong. I should also return shape type hints from org.eclipse.glsp.server.diagram.DiagramConfiguration.getNodeTypeHints(). Without this figures hints edge connection works wrong.

[glsp-bot]

[MoHcmp]

I need to some other things with edge creation:

1. I need to deny creation of edge from 'Translator' to 'Translator'. I can do this by checking source and target types in edge creation handler and returning empty oprional. But i get IllegalArgumentException.
2. I need to deny creation of several edges from 'Source'. I can do this by checking edges from model root and return empty optional. But i get IllegalArgumentException.
3. I need to deny creation of equal edges (example: edge source1->translator1 exists. I need to deny creation of second source1->translator1 edge). I can do this by checking edges from model root and return empty optional. But i get IllegalArgumentException.

Can i configure such edge creation rules?

[tortmayr]

Hi, it looks like you discovered a bug in our implementation of the CreateEdgeOperationHandler. Returning and empty Optional should not throw an exception. I will create an issue for this and provide a fix asap.
In the meantime, you could overwrite the 'executeOperation' method yourself and remove the part that throws an exception if the optional is empty. (https://github.com/eclipse-glsp/glsp-server/blob/370719caebe10c8709ff5c03d19b2631efe792e1/plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/operations/gmodel/CreateEdgeOperationHandler.java#L56)

[tortmayr]

I have created #195 to track this

[glsp-bot]

[MoHcmp]

As i understood i can deny edges from creation in CreateEdgeOperationHandlers, but i cannot do 'Cannot connect' animation on client?
Example: I need to deny creation of edge from 'Translator' to 'Translator' - check types in create operation and return empty optional. But client side did not have any feedback (edge just not created)

[tortmayr]

Hi, yes you are correct, there is currently no feedback for edge creation that got denied on the server side. In general there are a couple of issues with the current implementation of EdgeTypeHints and deriving client-side feeback. I have created #211 to track this