1 files changed, 204 insertions, 0 deletions
diff --git a/jpa/plugins/org.eclipse.jpt.ui/src/org/eclipse/jpt/ui/internal/listeners/SWTListChangeListenerWrapper.java b/jpa/plugins/org.eclipse.jpt.ui/src/org/eclipse/jpt/ui/internal/listeners/SWTListChangeListenerWrapper.java
new file mode 100644
index 0000000000..c70b1d2977
--- /dev/null
+++ b/jpa/plugins/org.eclipse.jpt.ui/src/org/eclipse/jpt/ui/internal/listeners/SWTListChangeListenerWrapper.java
@@ -0,0 +1,204 @@
+/*******************************************************************************
+ * Copyright (c) 2007, 2010 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.ui.internal.listeners;
+
+import org.eclipse.jpt.utility.model.event.ListAddEvent;
+import org.eclipse.jpt.utility.model.event.ListChangeEvent;
+import org.eclipse.jpt.utility.model.event.ListClearEvent;
+import org.eclipse.jpt.utility.model.event.ListMoveEvent;
+import org.eclipse.jpt.utility.model.event.ListRemoveEvent;
+import org.eclipse.jpt.utility.model.event.ListReplaceEvent;
+import org.eclipse.jpt.utility.model.listener.ListChangeListener;
+import org.eclipse.swt.widgets.Display;
+
+/**
+ * Wrap another list 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.
+ */
+public class SWTListChangeListenerWrapper
+	implements ListChangeListener
+{
+	private final ListChangeListener listener;
+
+	public SWTListChangeListenerWrapper(ListChangeListener listener) {
+		super();
+		if (listener == null) {
+			throw new NullPointerException();
+		}
+		this.listener = listener;
+	}
+
+	public void itemsAdded(ListAddEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.itemsAdded_(event);
+		} else {
+			this.executeOnUIThread(this.buildItemsAddedRunnable(event));
+		}
+	}
+
+	public void itemsRemoved(ListRemoveEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.itemsRemoved_(event);
+		} else {
+			this.executeOnUIThread(this.buildItemsRemovedRunnable(event));
+		}
+	}
+
+	public void itemsMoved(ListMoveEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.itemsMoved_(event);
+		} else {
+			this.executeOnUIThread(this.buildItemsMovedRunnable(event));
+		}
+	}
+
+	public void itemsReplaced(ListReplaceEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.itemsReplaced_(event);
+		} else {
+			this.executeOnUIThread(this.buildItemsReplacedRunnable(event));
+		}
+	}
+
+	public void listCleared(ListClearEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.listCleared_(event);
+		} else {
+			this.executeOnUIThread(this.buildListClearedRunnable(event));
+		}
+	}
+
+	public void listChanged(ListChangeEvent event) {
+		if (this.isExecutingOnUIThread()) {
+			this.listChanged_(event);
+		} else {
+			this.executeOnUIThread(this.buildListChangedRunnable(event));
+		}
+	}
+
+	private Runnable buildItemsAddedRunnable(final ListAddEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.itemsAdded_(event);
+			}
+			@Override
+			public String toString() {
+				return "items added"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private Runnable buildItemsRemovedRunnable(final ListRemoveEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.itemsRemoved_(event);
+			}
+			@Override
+			public String toString() {
+				return "items removed"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private Runnable buildItemsMovedRunnable(final ListMoveEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.itemsMoved_(event);
+			}
+			@Override
+			public String toString() {
+				return "items moved"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private Runnable buildItemsReplacedRunnable(final ListReplaceEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.itemsReplaced_(event);
+			}
+			@Override
+			public String toString() {
+				return "items replaced"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private Runnable buildListClearedRunnable(final ListClearEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.listCleared_(event);
+			}
+			@Override
+			public String toString() {
+				return "list cleared"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private Runnable buildListChangedRunnable(final ListChangeEvent event) {
+		return new Runnable() {
+			public void run() {
+				SWTListChangeListenerWrapper.this.listChanged_(event);
+			}
+			@Override
+			public String toString() {
+				return "list changed"; //$NON-NLS-1$
+			}
+		};
+	}
+
+	private boolean isExecutingOnUIThread() {
+		return Display.getCurrent() != null;
+	}
+
+	/**
+	 * {@link Display#asyncExec(Runnable)} seems to work OK;
+	 * but using {@link Display#syncExec(Runnable)} can somtimes make things
+	 * more predictable when debugging, at the risk of deadlocks.
+	 */
+	private void executeOnUIThread(Runnable r) {
+		Display.getDefault().asyncExec(r);
+//		Display.getDefault().syncExec(r);
+	}
+
+	void itemsAdded_(ListAddEvent event) {
+		this.listener.itemsAdded(event);
+	}
+
+	void itemsRemoved_(ListRemoveEvent event) {
+		this.listener.itemsRemoved(event);
+	}
+
+	void itemsMoved_(ListMoveEvent event) {
+		this.listener.itemsMoved(event);
+	}
+
+	void itemsReplaced_(ListReplaceEvent event) {
+		this.listener.itemsReplaced(event);
+	}
+
+	void listCleared_(ListClearEvent event) {
+		this.listener.listCleared(event);
+	}
+
+	void listChanged_(ListChangeEvent event) {
+		this.listener.listChanged(event);
+	}
+
+	@Override
+	public String toString() {
+		return "SWT(" + this.listener.toString() + ')'; //$NON-NLS-1$
+	}
+
+}