- Ensure that in each session, the hint how to create new connections is...

- Ensure that in each session, the hint how to create new connections is displayed until the user has managed to create three of them.
- (Side note): The current implementation cannot distinguish connections created interactively by the user, and connections created by a model-transformations. However, we can assume that a user who is able to issue a model-transformation also knows how to create a channel in the GUI.
refs 2229

org.fortiss.tooling.base.ui/trunk/src/org/fortiss/tooling/base/ui/editor/DiagramEditorBase.java

@@ -42,7 +42,11 @@ import org.eclipse.draw2d.ColorConstants;
 import org.eclipse.draw2d.IFigure;
 import org.eclipse.draw2d.geometry.Dimension;
 import org.eclipse.draw2d.geometry.Point;
+import org.eclipse.emf.common.notify.Adapter;
+import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.common.util.TreeIterator;
 import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.util.EContentAdapter;
 import org.eclipse.gef.EditDomain;
 import org.eclipse.gef.EditPart;
 import org.eclipse.gef.EditPartFactory;
@@ -86,6 +90,7 @@ import org.eclipse.ui.IEditorSite;
 import org.eclipse.ui.ISelectionListener;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.PartInitException;
+import org.fortiss.tooling.base.model.element.IConnection;
 import org.fortiss.tooling.base.model.element.IConnector;
 import org.fortiss.tooling.base.model.element.IHierarchicElement;
 import org.fortiss.tooling.base.ui.dnd.gef.ElementCompositionDropTargetListener;
@@ -135,13 +140,52 @@ public class DiagramEditorBase<T extends EObject> extends GEFEditorBase<T> imple
 	/** A container for editor actions. */
 	private final ActionRegistry actionRegistry = new ActionRegistry();
 
+	/**
+	 * Number of {@link IConnection}s to be created until the respective hint how to
+	 * create connections using the GUI is hidden.
+	 */
+	private static int numberOfConnectionsToBeCreatedUntilCreationHintIsHidden = 3;
+
+	/**
+	 * Adapter to watch for added {@link IConnection}s (used to update
+	 * {@link #numberOfConnectionsToBeCreatedUntilCreationHintIsHidden}).
+	 */
+	private static final Adapter addConnectionAdapter = new EContentAdapter() {
+		@Override
+		public void notifyChanged(Notification notification) {
+
+			super.notifyChanged(notification);
+			int eventType = notification.getEventType();
+
+			if(eventType == Notification.REMOVING_ADAPTER) {
+				return;
+			}
+
+			// Only count the notification by the IHierarchicElement owning the new IConnection
+			Object newValue = notification.getNewValue();
+			if(eventType == Notification.ADD && newValue instanceof IConnection &&
+					notification.getNotifier() == ((EObject)newValue).eContainer()) {
+
+				if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
+					numberOfConnectionsToBeCreatedUntilCreationHintIsHidden--;
+				} else if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden <= 0) {
+					// Hints will no longer be displayed: remove adapter
+					EObject rootObj = (EObject)notification.getNotifier();
+					while(rootObj.eContainer() != null) {
+						rootObj = rootObj.eContainer();
+					}
+					rootObj.eAdapters().remove(addConnectionAdapter);
+					for(TreeIterator<EObject> iter = rootObj.eAllContents(); iter.hasNext();) {
+						EObject obj = iter.next();
+						obj.eAdapters().remove(addConnectionAdapter);
+					}
+				}
+			}
+		}
+	};
+
 	/** Selection listener used to update selection actions. */
 	private final ISelectionListener selectionListener = new ISelectionListener() {
-		/** A counter for the selection. */
-		private int selectionCount = 0;
-
-		/** The number of times the hints about creating connections should be displayed. */
-		private final int HINTS_COUNT = 2;
 
 		/** {@inheritDoc} */
 		@Override
@@ -149,16 +193,18 @@ public class DiagramEditorBase<T extends EObject> extends GEFEditorBase<T> imple
 			EditPart ep = SelectionUtils.checkAndPickFirstSafe(selection, EditPart.class);
 			if(ep != null) {
 				Control control = ep.getViewer().getControl();
-				if(ep.getModel() instanceof IConnector && selectionCount < HINTS_COUNT) {
-					control.setToolTipText("Link two connectors by pressing ALT and dragging from source to target.");
-					selectionCount++;
-				} else if(ep.getModel() instanceof IHierarchicElement &&
-						selectionCount < HINTS_COUNT) {
-					control.setToolTipText("Create a connection by pressing ALT and dragging.");
-					selectionCount++;
-				} else {
-					control.setToolTipText("");
+				Object model = ep.getModel();
+
+				String hint = "";
+				if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
+					if(model instanceof IConnector) {
+						hint =
+								"Link two connectors by pressing ALT and dragging from source to target.";
+					} else if(model instanceof IHierarchicElement) {
+						hint = "Create a connection by pressing ALT and dragging.";
+					}
 				}
+				control.setToolTipText(hint);
 			}
 			updateActions(selectionActions);
 		}
@@ -172,6 +218,18 @@ public class DiagramEditorBase<T extends EObject> extends GEFEditorBase<T> imple
 		getSite().getWorkbenchWindow().getSelectionService()
 				.addSelectionListener(selectionListener);
 
+		// Install adapter to top-most object to watch for addition of IConnections.
+		if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
+			EObject model = getEditedObject();
+			EObject obj = model;
+			while(obj != null) {
+				obj = obj.eContainer();
+			}
+
+			if(!model.eAdapters().contains(addConnectionAdapter)) {
+				model.eAdapters().add(addConnectionAdapter);
+			}
+		}
 	}
 
 	/** {@inheritDoc} */