[news.eclipse.modeling.gmf] Problem creating link from derived class

[Martin Jacob <mj@xxxxxxxxxxxxxx>]

Hi,

I want to create a link  between nodes.
The ecore model is like this:
the nodes: 	Class A
a link:		Class B
another link 	Class BA -> Class B

I can create a link with class B but not with class BA. When I draw the connection with class BA 
than I get the following exception:

org.eclipse.core.commands.ExecutionException: While executing the operation, an exception occurred
at 
org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:519)
at org.eclipse.gmf.runtime.diagram.ui.parts.DiagramCommandStack.execute(DiagramCommandStack.java:205)
at org.eclipse.gmf.runtime.diagram.ui.parts.DiagramCommandStack.execute(DiagramCommandStack.java:168)
at org.eclipse.gmf.runtime.diagram.ui.parts.DiagramCommandStack.execute(DiagramCommandStack.java:155)
at org.eclipse.gef.tools.AbstractTool.executeCommand(AbstractTool.java:399)
at org.eclipse.gef.tools.AbstractTool.executeCurrentCommand(AbstractTool.java:411)
at 
org.eclipse.gmf.runtime.diagram.ui.tools.ConnectionCreationTool.handleCreateConnection(ConnectionCreationTool.java:341)
at 
org.eclipse.gmf.runtime.diagram.ui.tools.ConnectionCreationTool.handleButtonUp(ConnectionCreationTool.java:181)
at org.eclipse.gef.tools.AbstractTool.mouseUp(AbstractTool.java:1064)
at org.eclipse.gef.EditDomain.mouseUp(EditDomain.java:263)
at org.eclipse.gef.ui.parts.DomainEventDispatcher.dispatchMouseReleased(DomainEventDispatcher.java:374)
at org.eclipse.draw2d.LightweightSystem$EventHandler.mouseUp(LightweightSystem.java:538)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:207)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1003)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3823)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3422)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2382)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2346)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2198)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:493)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:288)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:488)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:113)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:193)
at 
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:386)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:549)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
at org.eclipse.equinox.launcher.Main.run(Main.java:1236)
at org.eclipse.equinox.launcher.Main.main(Main.java:1212)
Caused by: org.eclipse.core.runtime.AssertionFailedException: null argument:failed to create a view
at org.eclipse.core.runtime.Assert.isNotNull(Assert.java:86)
at org.eclipse.gmf.runtime.diagram.ui.commands.CreateCommand.doExecuteWithResult(CreateCommand.java:99)
at 
org.eclipse.gmf.runtime.emf.commands.core.command.AbstractTransactionalCommand.doExecute(AbstractTransactionalCommand.java:247)
at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:169)
at 
org.eclipse.gmf.runtime.common.core.command.CompositeCommand.doExecuteWithResult(CompositeCommand.java:403)
at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:135)
at 
org.eclipse.gmf.runtime.common.core.command.CompositeCommand.doExecuteWithResult(CompositeCommand.java:403)
at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:135)
at 
org.eclipse.gmf.runtime.common.core.command.CompositeCommand.doExecuteWithResult(CompositeCommand.java:403)
at org.eclipse.gmf.runtime.common.core.command.AbstractCommand.execute(AbstractCommand.java:135)
at 
org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:511)
... 37 more

I debug a bit and found that for Class BA is no ViewProvider registered but it is for class B. I 
have no idea where I could register this ViewProvider.

Does any one know how to solve the problem?

Thanks,		Martin