n-th attempt to display in a relevant manner the hint on connecting diagram elements

refs 2334

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

@@ -38,6 +38,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.conqat.ide.commons.ui.selection.SelectionUtils;
+import org.eclipse.core.runtime.Platform;
 import org.eclipse.draw2d.ColorConstants;
 import org.eclipse.draw2d.IFigure;
 import org.eclipse.draw2d.geometry.Dimension;
@@ -116,7 +117,7 @@ import org.fortiss.tooling.kernel.ui.service.IEditPartFactoryService;
  * @author hoelzl
  * @author $Author: aravantinos $
  * @version $Rev: 13954 $
- * @ConQAT.Rating YELLOW Hash: 12D04B9F7350EF3487A8E98778EE8424
+ * @ConQAT.Rating YELLOW Hash: A015DFFF58B1950E95D81CE8D7E39435
  */
 abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<T> implements
 		IPostSelectionProvider, ContextMenuContextProvider {
@@ -143,10 +144,15 @@ abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<
 	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.
+	 * Number of times the hint was displayed until we assume the user knows how to draw a
+	 * connection.
 	 */
-	private static int numberOfConnectionsToBeCreatedUntilCreationHintIsHidden = 3;
+	private static int numberOfHintDisplays = 1;
+
+	/** Returns numberOfHintDisplays *and decrements it*. */
+	private static boolean shouldDisplayHint() {
+		return numberOfHintDisplays-- >= 0;
+	}
 
 	/** Constructor. */
 	public CommonDiagramEditorBase(GraphicalViewer viewer, EditPartFactory factory) {
@@ -155,8 +161,8 @@ abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<
 	}
 
 	/**
-	 * Adapter to watch for added {@link IConnection}s (used to update
-	 * {@link #numberOfConnectionsToBeCreatedUntilCreationHintIsHidden}).
+	 * Adapter to watch for added {@link IConnection}s (used to update {@link #numberOfHintDisplays}
+	 * ).
 	 */
 	private static final Adapter addConnectionAdapter = new EContentAdapter() {
 		@Override
@@ -173,10 +179,7 @@ abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<
 			Object newValue = notification.getNewValue();
 			if(eventType == Notification.ADD && newValue instanceof IConnection &&
 					notification.getNotifier() == ((EObject)newValue).eContainer()) {
-
-				if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
-					numberOfConnectionsToBeCreatedUntilCreationHintIsHidden--;
-				} else if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden <= 0) {
+				if(!shouldDisplayHint()) {
 					// Hints will no longer be displayed: remove adapter
 					EObject rootObj = (EObject)notification.getNotifier();
 					while(rootObj.eContainer() != null) {
@@ -204,13 +207,16 @@ abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<
 				Object model = ep.getModel();
 
 				String hint = "";
-				if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
+				if(shouldDisplayHint()) {
+					String key = Platform.getOS().equals(Platform.OS_LINUX) ? "Ctrl" : "Alt";
+					String commonStr = " by pressing " + key + " and dragging";
 					if(model instanceof IConnector) {
-						hint =
-								"Link two connectors by pressing ALT and dragging from source to target.";
+						hint = "Link two connectors" + commonStr + "from source to target";
 					} else if(model instanceof IHierarchicElement) {
-						hint = "Create a connection by pressing ALT and dragging.";
+						hint = "Create a connection" + commonStr;
 					}
+					hint +=
+							" (select anything on the diagram to prevent further display of this message).";
 				}
 				control.setToolTipText(hint);
 			}
@@ -227,7 +233,7 @@ abstract class CommonDiagramEditorBase<T extends EObject> extends GEFEditorBase<
 				.addSelectionListener(selectionListener);
 
 		// Install adapter to top-most object to watch for addition of IConnections.
-		if(numberOfConnectionsToBeCreatedUntilCreationHintIsHidden > 0) {
+		if(shouldDisplayHint()) {
 			EObject model = getEditedObject();
 			EObject obj = model;
 			while(obj != null) {