| /******************************************************************************* |
| * Copyright (c) 2007, 2013 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.ui.internal.listeners; |
| |
| import org.eclipse.jpt.common.ui.internal.plugin.JptCommonUiPlugin; |
| import org.eclipse.jpt.common.ui.internal.swt.widgets.DisplayTools; |
| import org.eclipse.jpt.common.utility.internal.RunnableAdapter; |
| import org.eclipse.jpt.common.utility.internal.collection.SynchronizedQueue; |
| import org.eclipse.jpt.common.utility.model.event.PropertyChangeEvent; |
| import org.eclipse.jpt.common.utility.model.listener.PropertyChangeListener; |
| |
| /** |
| * Wrap another property change listener and forward events to it on the SWT |
| * UI thread, asynchronously if necessary. If the event arrived on the UI |
| * thread that is probably because it was initiated by a UI widget; as a |
| * result, we want to loop back synchronously so the events can be |
| * short-circuited. (Typically, the adapter(s) between a <em>property</em> and |
| * its corresponding UI widget are read-write; as opposed to the adapter(s) |
| * between a <em>collection</em> (or <em>list</em>) and its UI widget, which |
| * is read-only.) |
| * <p> |
| * Any events received earlier (on a non-UI thread) will be |
| * forwarded, in the order received, before the current event is forwarded. |
| */ |
| public class SWTPropertyChangeListenerWrapper |
| implements PropertyChangeListener |
| { |
| private final PropertyChangeListener listener; |
| private final SynchronizedQueue<PropertyChangeEvent> events = new SynchronizedQueue<PropertyChangeEvent>(); |
| |
| |
| public SWTPropertyChangeListenerWrapper(PropertyChangeListener listener) { |
| super(); |
| if (listener == null) { |
| throw new NullPointerException(); |
| } |
| this.listener = listener; |
| } |
| |
| public void propertyChanged(PropertyChangeEvent event) { |
| this.events.enqueue(event); |
| this.execute(new ForwardEventsRunnable()); |
| } |
| |
| /* CU private */ class ForwardEventsRunnable |
| extends RunnableAdapter |
| { |
| @Override |
| public void run() { |
| SWTPropertyChangeListenerWrapper.this.forwardEvents(); |
| } |
| } |
| |
| void forwardEvents() { |
| for (PropertyChangeEvent event : this.events.drain()) { |
| try { |
| this.listener.propertyChanged(event); |
| } catch (RuntimeException ex) { |
| JptCommonUiPlugin.instance().logError(ex); |
| } |
| } |
| } |
| |
| /** |
| * {@link DisplayTools#execute(Runnable)} seems to work OK; |
| * but using {@link DisplayTools#syncExec(Runnable)} can somtimes make things |
| * more predictable when debugging, at the risk of deadlocks. |
| */ |
| private void execute(Runnable r) { |
| DisplayTools.execute(r); |
| // SWTUtil.syncExec(r); |
| } |
| |
| @Override |
| public String toString() { |
| return "SWT(" + this.listener + ')'; //$NON-NLS-1$ |
| } |
| } |