[GEF] Use GEF EditPart interface where possible in WB Core

Our `EditPart` implementation has been aligned close enough to the GEF
interface that we can use it directly, rather than our own type. This
avoids several type-casts and should eventually allow us to mix
WindowBuilder and non-WindowBuilder edit-parts.

Author: ptziegler

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/gef/GenericContainersLayoutEditPolicyFactory.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -14,7 +14,6 @@
 
 import org.eclipse.wb.core.gef.policy.layout.ILayoutEditPolicyFactory;
 import org.eclipse.wb.core.model.JavaInfo;
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.graphical.policies.LayoutEditPolicy;
 import org.eclipse.wb.internal.core.gef.policy.layout.generic.FlowContainerLayoutEditPolicy;
 import org.eclipse.wb.internal.core.gef.policy.layout.generic.SimpleContainerLayoutEditPolicy;
@@ -23,6 +22,8 @@
 import org.eclipse.wb.internal.core.model.generic.SimpleContainer;
 import org.eclipse.wb.internal.core.model.generic.SimpleContainerFactory;
 
+import org.eclipse.gef.EditPart;
+
 import java.util.List;
 
 /**

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/requests/ChangeBoundsRequest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2024 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,11 +12,10 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.core.requests;
 
-import org.eclipse.wb.gef.core.EditPart;
-
 import org.eclipse.draw2d.geometry.Dimension;
 import org.eclipse.draw2d.geometry.Point;
 import org.eclipse.draw2d.geometry.Rectangle;
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.requests.DropRequest;
 import org.eclipse.gef.requests.GroupRequest;
 

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/requests/DragPermissionRequest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,8 +12,7 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.core.requests;
 
-import org.eclipse.wb.gef.core.EditPart;
-
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.Request;
 
 /**

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/tools/CreationTool.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2023 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,11 +12,11 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.core.tools;
 
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.core.IEditPartViewer;
 import org.eclipse.wb.gef.core.requests.CreateRequest;
 import org.eclipse.wb.gef.core.requests.ICreationFactory;
 
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.Request;
 
 /**
@@ -87,7 +87,7 @@ protected void selectAddedObjects() {
 		if (model != null) {
 			IEditPartViewer viewer = getCurrentViewer();
 			if (viewer != null) {
-				EditPart editPart = (EditPart) viewer.getEditPartRegistry().get(model);
+				EditPart editPart = viewer.getEditPartRegistry().get(model);
 				if (editPart != null) {
 					viewer.select(editPart);
 				}

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/tools/PasteTool.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2024 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,10 +12,10 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.core.tools;
 
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.core.IEditPartViewer;
 import org.eclipse.wb.gef.core.requests.PasteRequest;
 
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.Request;
 import org.eclipse.jface.viewers.StructuredSelection;
 
@@ -74,7 +74,7 @@ protected void selectAddedObjects() {
 		{
 			PasteRequest request = (PasteRequest) getTargetRequest();
 			for (Object model : request.getObjects()) {
-				editParts.add((EditPart) viewer.getEditPartRegistry().get(model));
+				editParts.add(viewer.getEditPartRegistry().get(model));
 			}
 		}
 		// select EditPart's

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/tools/SelectEditPartTracker.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2025 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,9 +12,9 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.core.tools;
 
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.core.IEditPartViewer;
 
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.RequestConstants;
 import org.eclipse.gef.requests.SelectionRequest;
 import org.eclipse.swt.SWT;

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/graphical/handles/MoveHandle.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2025 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -13,13 +13,13 @@
 package org.eclipse.wb.gef.graphical.handles;
 
 import org.eclipse.wb.draw2d.border.LineBorder;
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.core.tools.DragEditPartTracker;
 import org.eclipse.wb.gef.core.tools.Tool;
 import org.eclipse.wb.gef.graphical.GraphicalEditPart;
 
 import org.eclipse.draw2d.Cursors;
 import org.eclipse.draw2d.Locator;
+import org.eclipse.gef.EditPart;
 
 /**
  * A Handle used for moving {@link EditPart}s.

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/graphical/handles/ResizeHandle.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2023 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -13,11 +13,11 @@
 package org.eclipse.wb.gef.graphical.handles;
 
 import org.eclipse.wb.draw2d.RelativeLocator;
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.graphical.GraphicalEditPart;
 
 import org.eclipse.draw2d.Cursors;
 import org.eclipse.draw2d.Locator;
+import org.eclipse.gef.EditPart;
 
 /**
  * A Handle used to resize a {@link EditPart}s.

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/graphical/handles/SquareHandle.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,13 +12,13 @@
  *******************************************************************************/
 package org.eclipse.wb.gef.graphical.handles;
 
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.graphical.GraphicalEditPart;
 
 import org.eclipse.draw2d.ColorConstants;
 import org.eclipse.draw2d.Graphics;
 import org.eclipse.draw2d.Locator;
 import org.eclipse.draw2d.geometry.Rectangle;
+import org.eclipse.gef.EditPart;
 import org.eclipse.swt.graphics.Color;
 
 /**

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/graphical/policies/GraphicalEditPolicy.java

@@ -13,12 +13,12 @@
 package org.eclipse.wb.gef.graphical.policies;
 
 import org.eclipse.wb.draw2d.Layer;
-import org.eclipse.wb.gef.core.EditPart;
 import org.eclipse.wb.gef.core.IEditPartViewer;
 import org.eclipse.wb.gef.core.policies.EditPolicy;
 import org.eclipse.wb.gef.graphical.GraphicalEditPart;
 
 import org.eclipse.draw2d.IFigure;
+import org.eclipse.gef.EditPart;
 import org.eclipse.gef.LayerConstants;
 import org.eclipse.gef.editparts.LayerManager;