Bug 516725 - Show/Hide Status Bar context menu not updated I20170524-0800I20170523-2000

The proposed change fixes the bug by refreshing the menu label when the
status bar changes its visibility. The change works also when there are
multiple workbench windows.

Change-Id: If00b2ba2c3e7b23672bdfb80dd4459b8debcafb6
Signed-off-by: Patrik Suzzi <psuzzi@gmail.com>

1 files changed, 52 insertions, 10 deletions

diff --git a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/handlers/ToggleStatusBarHandler.java b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/handlers/ToggleStatusBarHandler.java
index d105aec61c0..109d96f7586 100644
--- a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/handlers/ToggleStatusBarHandler.java
+++ b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/handlers/ToggleStatusBarHandler.java
@@ -14,8 +14,9 @@ import java.util.HashMap;
 import java.util.Map;
 import org.eclipse.core.commands.AbstractHandler;
 import org.eclipse.core.commands.ExecutionEvent;
-import org.eclipse.core.commands.ExecutionException;
+import org.eclipse.e4.core.services.events.IEventBroker;
 import org.eclipse.e4.ui.model.application.ui.MUIElement;
+import org.eclipse.e4.ui.workbench.UIEvents;
 import org.eclipse.e4.ui.workbench.modeling.EModelService;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.commands.ICommandService;
@@ -26,6 +27,8 @@ import org.eclipse.ui.internal.WorkbenchWindow;
 import org.eclipse.ui.internal.services.IWorkbenchLocationService;
 import org.eclipse.ui.menus.UIElement;
 import org.eclipse.ui.services.IServiceScopes;
+import org.osgi.service.event.Event;
+import org.osgi.service.event.EventHandler;
 
 /**
  * Toggle the visibility of the status bar. Implementation of the
@@ -36,29 +39,68 @@ public class ToggleStatusBarHandler extends AbstractHandler implements IElementU
 
 	public static final String COMMAND_ID_TOGGLE_STATUSBAR = "org.eclipse.ui.window.togglestatusbar"; //$NON-NLS-1$
 
-	// id of the statusbar, as defined in the LegacyIDE.e4xmi
+	// id of the status bar, as defined in the LegacyIDE.e4xmi
 	private static final String BOTTOM_TRIM_ID = "org.eclipse.ui.trim.status"; //$NON-NLS-1$
 
+	// keep references of event handlers and brokers per each window
+	private HashMap<IWorkbenchWindow, EventHandler> eventHandlers = new HashMap<>();
+	private HashMap<IWorkbenchWindow, IEventBroker> eventBrokers = new HashMap<>();
+
 	@Override
-	public Object execute(ExecutionEvent event) throws ExecutionException {
+	public Object execute(ExecutionEvent event) {
 		IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindow(event);
 		if (!(window instanceof WorkbenchWindow))
 			return null;
+		// initialize event handler
+		if (!eventHandlers.containsKey(window)) {
+			initializeEventHandler(window);
+		}
+		// perform operation
 		MUIElement trimStatus = getTrimStatus((WorkbenchWindow) window);
-
 		if (trimStatus != null) {
 			// toggle statusbar visibility
 			trimStatus.setVisible(!trimStatus.isVisible());
-			// refresh menu item label, triggering updateElement()
-			ICommandService commandService = window.getService(ICommandService.class);
-			Map<String, WorkbenchWindow> filter = new HashMap<>();
-			filter.put(IServiceScopes.WINDOW_SCOPE, (WorkbenchWindow) window);
-			commandService.refreshElements(COMMAND_ID_TOGGLE_STATUSBAR, filter);
 		}
 		return null;
 	}
 
 	/**
+	 * @param window
+	 */
+	private void initializeEventHandler(IWorkbenchWindow window) {
+		final IEventBroker eventBroker = window.getService(IEventBroker.class);
+		eventBrokers.put(window, eventBroker);
+		EventHandler eventHandler = new EventHandler() {
+			@Override
+			public void handleEvent(Event event) {
+				Object element = event.getProperty(UIEvents.EventTags.ELEMENT);
+				// if the current-window trim is the event element
+				if (element != null && element == getTrimStatus((WorkbenchWindow) window)) {
+					// refresh menu item label, triggering updateElement()
+					ICommandService commandService = window.getService(ICommandService.class);
+					Map<String, WorkbenchWindow> filter = new HashMap<>();
+					filter.put(IServiceScopes.WINDOW_SCOPE, (WorkbenchWindow) window);
+					commandService.refreshElements(COMMAND_ID_TOGGLE_STATUSBAR, filter);
+				}
+			}
+		};
+		eventHandlers.put(window, eventHandler);
+		eventBroker.subscribe(UIEvents.UIElement.TOPIC_VISIBLE, eventHandler);
+	}
+
+	@Override
+	public void dispose() {
+		for (IWorkbenchWindow w : eventHandlers.keySet()) {
+			IEventBroker eventBroker = eventBrokers.get(w);
+			EventHandler eventHandler = eventHandlers.get(w);
+			if (eventBroker != null && eventHandler != null) {
+				eventBroker.unsubscribe(eventHandler);
+			}
+		}
+		super.dispose();
+	}
+
+	/**
 	 * Updates the visibilty status of the element.
 	 */
 	@Override
@@ -76,7 +118,7 @@ public class ToggleStatusBarHandler extends AbstractHandler implements IElementU
 		}
 	}
 
-	/* Get the MUIElement representing the status bar */
+	/* Get the MUIElement representing the status bar for the given window */
 	private static MUIElement getTrimStatus(WorkbenchWindow window) {
 		EModelService modelService = window.getService(EModelService.class);
 		MUIElement searchRoot = window.getModel();