--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.core.databinding.observable/src/org/eclipse/core/internal/databinding/observable/ProxyObservableSet.d	Tue Apr 21 10:55:51 2009 +0200
@@ -0,0 +1,87 @@
+/*******************************************************************************
+ * Copyright (c) 2006, 2008 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
+ *     Matthew Hall - bug 208332
+ *******************************************************************************/
+
+package org.eclipse.core.internal.databinding.observable;
+
+import java.util.Collections;
+import java.util.Set;
+
+import org.eclipse.core.databinding.observable.IStaleListener;
+import org.eclipse.core.databinding.observable.StaleEvent;
+import org.eclipse.core.databinding.observable.set.AbstractObservableSet;
+import org.eclipse.core.databinding.observable.set.IObservableSet;
+import org.eclipse.core.databinding.observable.set.ISetChangeListener;
+import org.eclipse.core.databinding.observable.set.SetChangeEvent;
+
+/**
+ * Wraps an observable set. This object acts like an exact copy of the original
+ * set, and tracks all the changes in the original. The only difference is that
+ * disposing the wrapper will not dispose the original. You can use this
+ * whenever you need to return an IObservableSet from a method that expects the
+ * caller to dispose the set, but you have an IObservableSet that you don't want
+ * disposed.
+ */
+public class ProxyObservableSet : AbstractObservableSet {
+    private IObservableSet wrappedSet;
+    private Object elementType;
+
+    private ISetChangeListener setChangeListener = new class() ISetChangeListener {
+        public void handleSetChange(SetChangeEvent event) {
+            fireSetChange(event.diff);
+        }
+    };
+
+    private IStaleListener staleListener = new class() IStaleListener {
+        public void handleStale(StaleEvent staleEvent) {
+            fireStale();
+        }
+    };
+
+    /**
+     * Constructs a ProxyObservableSet that tracks the state of the given set.
+     * 
+     * @param wrappedSet
+     *            the set being wrapped
+     */
+    public this(IObservableSet wrappedSet) {
+        super(wrappedSet.getRealm());
+        this.wrappedSet = wrappedSet;
+        this.elementType = wrappedSet.getElementType();
+        wrappedSet.addSetChangeListener(setChangeListener);
+        wrappedSet.addStaleListener(staleListener);
+    }
+
+    protected Set getWrappedSet() {
+        return wrappedSet is null ? Collections.EMPTY_SET : wrappedSet;
+    }
+
+    public Object getElementType() {
+        return elementType;
+    }
+
+    public bool isStale() {
+        getterCalled();
+        return wrappedSet is null ? false : wrappedSet.isStale();
+    }
+
+    public void dispose() {
+        if (wrappedSet !is null) {
+            wrappedSet.removeSetChangeListener(setChangeListener);
+            setChangeListener = null;
+            wrappedSet.removeStaleListener(staleListener);
+            staleListener = null;
+            wrappedSet = null;
+        }
+        elementType = null;
+        super.dispose();
+    }
+}