### Eclipse Workspace Patch 1.0
#P org.eclipse.core.databinding
Index: src/org/eclipse/core/databinding/TargetsListener.java
===================================================================
RCS file: src/org/eclipse/core/databinding/TargetsListener.java
diff -N src/org/eclipse/core/databinding/TargetsListener.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/org/eclipse/core/databinding/TargetsListener.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,162 @@
+/*******************************************************************************
+ * Copyright (c) 2009 IBM Corporation and others.
+ * 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:
+ *     IBM Corporation - initial API and implementation
+ ******************************************************************************/
+
+package org.eclipse.core.databinding;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.eclipse.core.databinding.observable.ChangeEvent;
+import org.eclipse.core.databinding.observable.IChangeListener;
+import org.eclipse.core.databinding.observable.IObservable;
+import org.eclipse.core.databinding.observable.list.IListChangeListener;
+import org.eclipse.core.databinding.observable.list.IObservableList;
+import org.eclipse.core.databinding.observable.list.ListChangeEvent;
+import org.eclipse.core.databinding.observable.list.ListDiff;
+import org.eclipse.core.databinding.observable.list.ListDiffEntry;
+
+/**
+ * A TargetListener listens to changes of any target of any
+ * ValidationStatusProvider in the given context.
+ * 
+ * @since 1.2
+ * 
+ */
+public class TargetsListener {
+	/**
+	 * Creates a TargetsListener. Once when any target changes the listener will
+	 * be notified and the TargetsListener will be disposed.
+	 * 
+	 * @param context
+	 * @param listener
+	 * @return The TargetsListener is returned so it can be disposed even if no
+	 *         change occurs. It should not be used for anything else.
+	 */
+	public static TargetsListener listenOnce(DataBindingContext context, final IChangeListener listener) {
+		final TargetsListener targetsListener = new TargetsListener(context);
+		targetsListener.addChangeListener(new IChangeListener() {
+			public void handleChange(ChangeEvent event) {
+				listener.handleChange(event);
+				targetsListener.dispose();
+			}
+		});
+		return targetsListener;
+	}
+
+	private final DataBindingContext context;
+	private final List changeListeners = new ArrayList();
+
+	private IChangeListener targetListener = new IChangeListener() {
+		public void handleChange(ChangeEvent event) {
+			Iterator iterator = changeListeners.iterator();
+			while (iterator.hasNext()) {
+				IChangeListener listener = (IChangeListener) iterator.next();
+				listener.handleChange(event);
+			}
+		}
+	};
+	private IListChangeListener validationStatusProvidersListener = new IListChangeListener() {
+		public void handleListChange(ListChangeEvent event) {
+			ListDiff diff = event.diff;
+			ListDiffEntry[] differences = diff.getDifferences();
+			for (int i = 0; i < differences.length; i++) {
+				ListDiffEntry listDiffEntry = differences[i];
+				ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) listDiffEntry
+						.getElement();
+				IObservableList targets = validationStatusProvider.getTargets();
+				if (listDiffEntry.isAddition()) {
+					targets.addListChangeListener(validationStatusProviderTargetsListener);
+					for (Iterator it = targets.iterator(); it.hasNext();) {
+						((IObservable) it.next()).addChangeListener(targetListener);
+					}
+				} else {
+					targets.removeListChangeListener(validationStatusProviderTargetsListener);
+					for (Iterator it = targets.iterator(); it.hasNext();) {
+						((IObservable) it.next()).removeChangeListener(targetListener);
+					}
+				}
+			}
+		}
+	};
+	private IListChangeListener validationStatusProviderTargetsListener = new IListChangeListener() {
+		public void handleListChange(ListChangeEvent event) {
+			ListDiff diff = event.diff;
+			ListDiffEntry[] differences = diff.getDifferences();
+			for (int i = 0; i < differences.length; i++) {
+				ListDiffEntry listDiffEntry = differences[i];
+				IObservable target = (IObservable) listDiffEntry.getElement();
+				if (listDiffEntry.isAddition()) {
+					target.addChangeListener(targetListener);
+				} else {
+					target.removeChangeListener(targetListener);
+				}
+			}
+		}
+	};
+
+	/**
+	 * A TargetListener listens to changes of any target of any
+	 * ValidationStatusProvider in the given context.
+	 * 
+	 * @param context
+	 */
+	public TargetsListener(DataBindingContext context) {
+		this.context = context;
+		IObservableList validationStatusProviders = context.getValidationStatusProviders();
+		validationStatusProviders.addListChangeListener(validationStatusProvidersListener);
+		for (Iterator iter = validationStatusProviders.iterator(); iter.hasNext();) {
+			ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) iter.next();
+			IObservableList targets = validationStatusProvider.getTargets();
+			targets.addListChangeListener(validationStatusProviderTargetsListener);
+			for (Iterator it = targets.iterator(); it.hasNext();) {
+				((IObservable) it.next()).addChangeListener(targetListener);
+			}
+		}
+	}
+
+	/**
+	 * Adds the {@link IChangeListener} to the list of target listeners.
+	 * 
+	 * @param listener
+	 *            The IChangeListener that will be notified in case any target
+	 *            changes.
+	 * @since 1.2
+	 */
+	public final void addChangeListener(IChangeListener listener) {
+		changeListeners.add(listener);
+	}
+
+	/**
+	 * Removes the {@link IChangeListener} from the list of target listeners.
+	 * 
+	 * @param listener
+	 *            The IChangeListener that should no longer be notified in case
+	 *            any target changes.
+	 * @since 1.2
+	 */
+	public final void removeChangeListener(IChangeListener listener) {
+		changeListeners.remove(listener);
+	}
+
+	public void dispose() {
+		IObservableList validationStatusProviders = context.getValidationStatusProviders();
+		validationStatusProviders.removeListChangeListener(validationStatusProvidersListener);
+		for (Iterator iter = validationStatusProviders.iterator(); iter.hasNext();) {
+			ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) iter.next();
+			IObservableList targets = validationStatusProvider.getTargets();
+			targets.removeListChangeListener(validationStatusProviderTargetsListener);
+			for (Iterator it = targets.iterator(); it.hasNext();) {
+				((IObservable) it.next()).removeChangeListener(targetListener);
+			}
+		}
+	}
+}
#P org.eclipse.jface.databinding
Index: src/org/eclipse/jface/databinding/dialog/DialogPageSupport.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/dialog/DialogPageSupport.java,v
retrieving revision 1.2
diff -u -r1.2 DialogPageSupport.java
--- src/org/eclipse/jface/databinding/dialog/DialogPageSupport.java	23 Oct 2008 17:47:08 -0000	1.2
+++ src/org/eclipse/jface/databinding/dialog/DialogPageSupport.java	28 Feb 2009 01:46:09 -0000
@@ -15,21 +15,13 @@
 
 package org.eclipse.jface.databinding.dialog;
 
-import java.util.Iterator;
-
 import org.eclipse.core.databinding.AggregateValidationStatus;
 import org.eclipse.core.databinding.DataBindingContext;
-import org.eclipse.core.databinding.ValidationStatusProvider;
+import org.eclipse.core.databinding.TargetsListener;
 import org.eclipse.core.databinding.observable.ChangeEvent;
 import org.eclipse.core.databinding.observable.IChangeListener;
-import org.eclipse.core.databinding.observable.IObservable;
 import org.eclipse.core.databinding.observable.IStaleListener;
 import org.eclipse.core.databinding.observable.StaleEvent;
-import org.eclipse.core.databinding.observable.list.IListChangeListener;
-import org.eclipse.core.databinding.observable.list.IObservableList;
-import org.eclipse.core.databinding.observable.list.ListChangeEvent;
-import org.eclipse.core.databinding.observable.list.ListDiff;
-import org.eclipse.core.databinding.observable.list.ListDiffEntry;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.databinding.observable.value.IValueChangeListener;
 import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
@@ -68,55 +60,9 @@
 	private DataBindingContext dbc;
 	private IObservableValue aggregateStatus;
 	private boolean uiChanged = false;
-	private IChangeListener uiChangeListener = new IChangeListener() {
-		public void handleChange(ChangeEvent event) {
-			handleUIChanged();
-		}
-	};
-	private IListChangeListener validationStatusProvidersListener = new IListChangeListener() {
-		public void handleListChange(ListChangeEvent event) {
-			ListDiff diff = event.diff;
-			ListDiffEntry[] differences = diff.getDifferences();
-			for (int i = 0; i < differences.length; i++) {
-				ListDiffEntry listDiffEntry = differences[i];
-				ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) listDiffEntry
-						.getElement();
-				IObservableList targets = validationStatusProvider.getTargets();
-				if (listDiffEntry.isAddition()) {
-					targets
-							.addListChangeListener(validationStatusProviderTargetsListener);
-					for (Iterator it = targets.iterator(); it.hasNext();) {
-						((IObservable) it.next())
-								.addChangeListener(uiChangeListener);
-					}
-				} else {
-					targets
-							.removeListChangeListener(validationStatusProviderTargetsListener);
-					for (Iterator it = targets.iterator(); it.hasNext();) {
-						((IObservable) it.next())
-								.removeChangeListener(uiChangeListener);
-					}
-				}
-			}
-		}
-	};
-	private IListChangeListener validationStatusProviderTargetsListener = new IListChangeListener() {
-		public void handleListChange(ListChangeEvent event) {
-			ListDiff diff = event.diff;
-			ListDiffEntry[] differences = diff.getDifferences();
-			for (int i = 0; i < differences.length; i++) {
-				ListDiffEntry listDiffEntry = differences[i];
-				IObservable target = (IObservable) listDiffEntry.getElement();
-				if (listDiffEntry.isAddition()) {
-					target.addChangeListener(uiChangeListener);
-				} else {
-					target.removeChangeListener(uiChangeListener);
-				}
-			}
-		}
-	};
 	protected IStatus currentStatus;
 	protected boolean currentStatusStale;
+	private TargetsListener targetsListener;
 
 	/**
 	 * @param dialogPage
@@ -161,19 +107,11 @@
 		currentStatus = (IStatus) aggregateStatus.getValue();
 		currentStatusStale = aggregateStatus.isStale();
 		handleStatusChanged();
-		dbc.getValidationStatusProviders().addListChangeListener(
-				validationStatusProvidersListener);
-		for (Iterator it = dbc.getValidationStatusProviders().iterator(); it
-				.hasNext();) {
-			ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) it
-					.next();
-			IObservableList targets = validationStatusProvider.getTargets();
-			targets
-					.addListChangeListener(validationStatusProviderTargetsListener);
-			for (Iterator iter = targets.iterator(); iter.hasNext();) {
-				((IObservable) iter.next()).addChangeListener(uiChangeListener);
+		targetsListener = TargetsListener.listenOnce(dbc, new IChangeListener() {
+			public void handleChange(ChangeEvent event) {
+				handleUIChanged();
 			}
-		}
+		});
 	}
 
 	/**
@@ -184,20 +122,6 @@
 		if (currentStatus != null) {
 			handleStatusChanged();
 		}
-		dbc.getValidationStatusProviders().removeListChangeListener(
-				validationStatusProvidersListener);
-		for (Iterator it = dbc.getValidationStatusProviders().iterator(); it
-				.hasNext();) {
-			ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) it
-					.next();
-			IObservableList targets = validationStatusProvider.getTargets();
-			targets
-					.removeListChangeListener(validationStatusProviderTargetsListener);
-			for (Iterator iter = targets.iterator(); iter.hasNext();) {
-				((IObservable) iter.next())
-						.removeChangeListener(uiChangeListener);
-			}
-		}
 	}
 
 	/**
@@ -298,26 +222,10 @@
 	public void dispose() {
 		aggregateStatus.dispose();
 		if (!uiChanged) {
-			for (Iterator it = dbc.getValidationStatusProviders().iterator(); it
-					.hasNext();) {
-				ValidationStatusProvider validationStatusProvider = (ValidationStatusProvider) it
-						.next();
-				IObservableList targets = validationStatusProvider.getTargets();
-				targets
-						.removeListChangeListener(validationStatusProviderTargetsListener);
-				for (Iterator iter = targets.iterator(); iter.hasNext();) {
-					((IObservable) iter.next())
-							.removeChangeListener(uiChangeListener);
-				}
-			}
-			dbc.getValidationStatusProviders().removeListChangeListener(
-					validationStatusProvidersListener);
+			targetsListener.dispose();
 		}
 		aggregateStatus = null;
 		dbc = null;
-		uiChangeListener = null;
-		validationStatusProvidersListener = null;
-		validationStatusProviderTargetsListener = null;
 		dialogPage = null;
 	}
 }