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Bug In GEF MVC Tutorial [message #1796191]

Mon, 08 October 2018 04:03

Eclipse User

I just completed the GEF MVC tutorial and I am getting an error where it says that the "MindMapConnectionPart cannot be cast to ITransformableContentPart". This error occurs if I select the whole content and try to resize it. I cloned the GEF tutorial file from git and the error occurs in there too.

the stack:

java.lang.ClassCastException: com.itemis.gef.tutorial.mindmap.parts.MindMapConnectionPart cannot be cast to org.eclipse.gef.mvc.fx.parts.ITransformableContentPart
	at org.eclipse.gef.mvc.fx.handlers.ResizeTranslateFirstAnchorageOnHandleDragHandler.getTargetPart(ResizeTranslateFirstAnchorageOnHandleDragHandler.java:203)
	at org.eclipse.gef.mvc.fx.handlers.ResizeTranslateFirstAnchorageOnHandleDragHandler.isMultiSelection(ResizeTranslateFirstAnchorageOnHandleDragHandler.java:222)
	at org.eclipse.gef.mvc.fx.handlers.ResizeTranslateFirstAnchorageOnHandleDragHandler.isResizeTranslate(ResizeTranslateFirstAnchorageOnHandleDragHandler.java:254)
	at org.eclipse.gef.mvc.fx.handlers.ResizeTranslateFirstAnchorageOnHandleDragHandler.startDrag(ResizeTranslateFirstAnchorageOnHandleDragHandler.java:282)
	at org.eclipse.gef.mvc.fx.gestures.ClickDragGesture.press(ClickDragGesture.java:426)
	at org.eclipse.gef.mvc.fx.gestures.ClickDragGesture$1.handle(ClickDragGesture.java:106)
	at org.eclipse.gef.mvc.fx.gestures.ClickDragGesture$1.handle(ClickDragGesture.java:1)
	at com.sun.javafx.event.CompositeEventHandler$NormalEventFilterRecord.handleCapturingEvent(CompositeEventHandler.java:282)
	at com.sun.javafx.event.CompositeEventHandler.dispatchCapturingEvent(CompositeEventHandler.java:98)
	at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:223)
	at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:180)
	at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
	at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
	at javafx.event.Event.fireEvent(Event.java:198)
	at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
	at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
	at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
	at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
	at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
	at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
	at com.sun.glass.ui.View.notifyMouse(View.java:937)

Attachment: GefMindMap.jpeg
(Size: 449.11KB, Downloaded 125 times)

Re: Bug In GEF MVC Tutorial [message #1802541 is a reply to message #1796191]

Mon, 11 February 2019 12:16

Eclipse User

Hi Servan,

thank you for reporting this issue. This should not happen of course.

There are multiple underlying problems here, I believe:

1) The name of the handler in the stack trace (ResizeTranslateFirstAnchorageOnHandleDragHandler) implies that it should only be used to resize/translate a single, resizable and transformable content part for which resize/translate handles were generated for the user to interact with. I believe that the same handles that are generated for a single selection are also generated for a multi-selection. Therefore, the same handler is executed also for the multi-selection.

2) The connection part does not implement IBendableContentPart. Therefore, it will not work together nicely with the other GEF concepts w.r.t. connections (e.g. bending).

There are several options for implementing resize of a multi-selection. One option is subclassing both ResizeTranslateFirstAnchorageOnHandleDragHandler and ResizeTransformSelectedOnHandleDragHandler. The RTFAOHDH needs to be disabled for multi-selections. The RTSOHDH needs to be disabled for single selections and it needs to disregard connection parts.

Alternatively, you could make ConnectionPart implement IBendableContentPart.

Best regards,
Matthias

Re: Bug In GEF MVC Tutorial [message #1803112 is a reply to message #1802541]

Fri, 22 February 2019 10:17

Eclipse User

Hi Matthias

Thank you very much I implemented IBendableContentPart<Connection> to the ConnectionPart and now it works like a charm.

Best regards
Servan Kilec

[Updated on: Wed, 20 March 2019 04:34] by Moderator

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