Change constructor of OverviewOutlinePage

- It only needs the ScalableFreeformRootEditPart which AbstractDiagramEditor can supply and check it's not null

- Also add some null checks

Author: Phillipus

com.archimatetool.editor/src/com/archimatetool/editor/diagram/AbstractDiagramEditor.java

@@ -1004,10 +1004,11 @@ public <T> T getAdapter(Class<T> adapter) {
         }
 
         /*
-         * Return the singleton Outline Page
+         * Return the Outline Page
          */
-        if(adapter == IContentOutlinePage.class && getGraphicalViewer() != null) {
-            return adapter.cast(new OverviewOutlinePage(this));
+        if(adapter == IContentOutlinePage.class && getGraphicalViewer() != null
+                                                && getGraphicalViewer().getRootEditPart() instanceof ScalableFreeformRootEditPart editPart) {
+            return adapter.cast(new OverviewOutlinePage(editPart));
         }
 
         /*
@@ -1034,7 +1035,7 @@ public <T> T getAdapter(Class<T> adapter) {
 
         // Find/Replace Provider
         if(adapter == IFindReplaceProvider.class) {
-            if(fFindReplaceProvider == null) {
+            if(fFindReplaceProvider == null && getGraphicalViewer() != null) {
                 fFindReplaceProvider = new DiagramEditorFindReplaceProvider(getGraphicalViewer());
             }
             return adapter.cast(fFindReplaceProvider);
@@ -1087,5 +1088,6 @@ public void dispose() {
         fDiagramModel = null;
 
         fContextActivation = null;
+        fFindReplaceProvider = null;
     }
 }

com.archimatetool.editor/src/com/archimatetool/editor/diagram/OverviewOutlinePage.java

@@ -9,7 +9,6 @@
 import org.eclipse.draw2d.MarginBorder;
 import org.eclipse.draw2d.Viewport;
 import org.eclipse.draw2d.parts.ScrollableThumbnail;
-import org.eclipse.gef.EditPart;
 import org.eclipse.gef.LayerConstants;
 import org.eclipse.gef.editparts.ScalableFreeformRootEditPart;
 import org.eclipse.help.HelpSystem;
@@ -36,52 +35,48 @@
  */
 public class OverviewOutlinePage extends Page implements IContentOutlinePage, IContextProvider {
 
-    private Canvas fCanvas;
-    private ScrollableThumbnail fThumbnail;
-    private ScalableFreeformRootEditPart fEditPart;
+    private ScalableFreeformRootEditPart editPart;
+    private Canvas canvas;
+    private ScrollableThumbnail thumbnail;
 
     public static String HELP_ID = "com.archimatetool.help.outlineViewHelp"; //$NON-NLS-1$
 
     /**
-     * Creates a new OverviewOutlinePage instance.
-     * @param abstractDiagramEditor 
+     * Creates a new OverviewOutlinePage instance for editPart
      */
-    public OverviewOutlinePage(IDiagramModelEditor editor) {
-        fEditPart = (ScalableFreeformRootEditPart)editor.getAdapter(EditPart.class);
+    public OverviewOutlinePage(ScalableFreeformRootEditPart editPart) {
+        this.editPart = editPart;
     }
 
     @Override
     public void createControl(Composite parent) {
-        if(fEditPart == null) {
-            return;
-        }
-        
-        // create canvas and lws
-        fCanvas = new Canvas(parent, SWT.NONE);
-        LightweightSystem lws = new LightweightSystem(fCanvas);
+        // Create Canvas and LWS
+        canvas = new Canvas(parent, SWT.NONE);
+        LightweightSystem lws = new LightweightSystem(canvas);
 
-        fThumbnail = new ScrollableThumbnail((Viewport)fEditPart.getFigure());
-        fThumbnail.setUseScaledGraphics(false);
-        fThumbnail.setSource(fEditPart.getLayer(LayerConstants.PRINTABLE_LAYERS));
-        fThumbnail.setBorder(new MarginBorder(3));
-        lws.setContents(fThumbnail);
+        // Thumbnail is contents of LWS
+        thumbnail = new ScrollableThumbnail((Viewport)editPart.getFigure());
+        thumbnail.setUseScaledGraphics(false);
+        thumbnail.setSource(editPart.getLayer(LayerConstants.PRINTABLE_LAYERS));
+        thumbnail.setBorder(new MarginBorder(3));
+        lws.setContents(thumbnail);
 
         // Help
-        PlatformUI.getWorkbench().getHelpSystem().setHelp(fCanvas, HELP_ID);
+        PlatformUI.getWorkbench().getHelpSystem().setHelp(canvas, HELP_ID);
     }
 
     @Override
     public void dispose() {
-        if(fThumbnail != null) {
-            fThumbnail.deactivate();
-            fThumbnail = null;
+        if(thumbnail != null) {
+            thumbnail.deactivate();
+            thumbnail = null;
         }
         super.dispose();
     }
 
     @Override
     public Control getControl() {
-        return fCanvas;
+        return canvas;
     }
 
     @Override