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Bug 349042

Summary: Nullpointer exception in XYLayoutEditPolicy
Product: [Modeling] GMF-Runtime Reporter: Andreas Muelder <Andreas.Muelder>
Component: GeneralAssignee: Project Inbox <gmf-runtime-inbox>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: P3 CC: an.mayer, apupier, yann.tanguy
Version: unspecified   
Target Milestone: 1.6.0   
Hardware: PC   
OS: Windows 7   
Whiteboard:
Attachments:
Description Flags
Patch for bug 349042 none

Description Andreas Muelder CLA 2011-06-10 10:43:46 EDT 
Build Identifier:  I20110519-1138

A NullpointerException is thrown when moving an EditPart from a FlowLayout or ToolbarLayout to XYLayout. 
In this case, GEFs XYLayoutEditPolicy return null in getCurrentConstraintFor()
which is not handled in GMF XYLayoutEditPolicy. This can be reproduced in GMFs logic example.

This is related to GEF bug #86473

Reproducible: Always

Steps to Reproduce:
1. Create alogic example diagram
2. Create a Logic flow with a LED in it.
3. drag the LED outside of the logic flow -> the exception is thrown.
Comment 1 Andreas Muelder CLA 2011-06-10 11:04:28 EDT 
Created attachment 197790 [details]
Patch for bug 349042

Patch attached...
Comment 2 Andreas Mayer CLA 2011-11-03 11:02:16 EDT 
There is a similar issue with edit parts that have a non-Rectangle constraint:  

java.lang.ClassCastException: org.eclipse.gmf.runtime.diagram.ui.figures.LabelLocator cannot be cast to org.eclipse.draw2d.geometry.Rectangle
	at org.eclipse.gef.editpolicies.XYLayoutEditPolicy.getCurrentConstraintFor(XYLayoutEditPolicy.java:102)
	at org.eclipse.gef.editpolicies.XYLayoutEditPolicy.getConstraintFor(XYLayoutEditPolicy.java:55)
	at org.eclipse.gef.editpolicies.ConstrainedLayoutEditPolicy.getConstraintFor(ConstrainedLayoutEditPolicy.java:244)
	at org.eclipse.gmf.runtime.diagram.ui.editpolicies.XYLayoutEditPolicy.getConstraintFor(XYLayoutEditPolicy.java:226)
	at org.eclipse.gef.editpolicies.ConstrainedLayoutEditPolicy.getAddCommand(ConstrainedLayoutEditPolicy.java:184)
	at org.eclipse.gef.editpolicies.LayoutEditPolicy.getCommand(LayoutEditPolicy.java:216)
	at org.eclipse.gef.editpolicies.ConstrainedLayoutEditPolicy.getCommand(ConstrainedLayoutEditPolicy.java:214)
	at org.eclipse.gmf.runtime.diagram.ui.editpolicies.XYLayoutEditPolicy.getCommand(XYLayoutEditPolicy.java:325)
	at org.eclipse.gef.editparts.AbstractEditPart.getCommand(AbstractEditPart.java:502)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart.access$1(GraphicalEditPart.java:1)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart$1.run(GraphicalEditPart.java:482)
	at org.eclipse.emf.transaction.impl.TransactionalEditingDomainImpl.runExclusive(TransactionalEditingDomainImpl.java:328)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart.getCommand(GraphicalEditPart.java:477)
	at org.eclipse.gmf.runtime.diagram.ui.editpolicies.DragDropEditPolicy.getDropCommand(DragDropEditPolicy.java:112)
	at org.eclipse.gmf.runtime.diagram.ui.editpolicies.DiagramDragDropEditPolicy.getDropCommand(DiagramDragDropEditPolicy.java:151)
	at org.eclipse.gmf.runtime.diagram.ui.editpolicies.DragDropEditPolicy.getCommand(DragDropEditPolicy.java:75)
	at org.eclipse.gef.editparts.AbstractEditPart.getCommand(AbstractEditPart.java:502)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart.access$1(GraphicalEditPart.java:1)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart$1.run(GraphicalEditPart.java:482)
	at org.eclipse.emf.transaction.impl.TransactionalEditingDomainImpl.runExclusive(TransactionalEditingDomainImpl.java:328)
	at org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart.getCommand(GraphicalEditPart.java:477)
	at org.eclipse.gmf.runtime.diagram.ui.tools.DragEditPartsTrackerEx.getCommand(DragEditPartsTrackerEx.java:63)
	at org.eclipse.gef.tools.DragEditPartsTracker.handleDragInProgress(DragEditPartsTracker.java:370)
	at org.eclipse.gmf.runtime.diagram.ui.tools.DragEditPartsTrackerEx.handleDragInProgress(DragEditPartsTrackerEx.java:177)
	at org.eclipse.gef.tools.AbstractTool.mouseDrag(AbstractTool.java:1114)
	at org.eclipse.gef.tools.SelectionTool.mouseDrag(SelectionTool.java:538)
	at org.eclipse.gef.EditDomain.mouseDrag(EditDomain.java:259)

You can reproduce this, for example, in the Tai Pan diagram editor:

1. Create a port and give it a name.
2. Click on the name to select it.
3. Move the cursor to the name's boundaries until the cursor changes into a cross with arrowheads.
4. Now grab the label and drag it around.
5. You will see the above ClassCastException.

This issue can be fixed by adding the following to XYLayoutEditPolicy:

    @Override
    protected Rectangle getCurrentConstraintFor(GraphicalEditPart child) {
        IFigure figure = child.getFigure();
        Object constraint = figure.getParent().getLayoutManager().getConstraint(figure);
        return constraint instanceof Rectangle 
                ? (Rectangle) constraint 
                : null;
    }
Comment 3 Aurelien Pupier CLA 2012-09-19 12:42:55 EDT 
commit done 13/03/12