--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.core.databinding.observable/src/org/eclipse/core/internal/databinding/observable/ConstantObservableValue.d	Tue Apr 21 10:55:51 2009 +0200
@@ -0,0 +1,110 @@
+/*******************************************************************************
+ * Copyright (c) 2005, 2007-2008 Matt Carter 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:
+ *     Matt Carter - initial API and implementation (bug 212518)
+ *     Matthew Hall - bug 212518
+ *******************************************************************************/
+package org.eclipse.core.internal.databinding.observable;
+
+import org.eclipse.core.databinding.observable.IChangeListener;
+import org.eclipse.core.databinding.observable.IStaleListener;
+import org.eclipse.core.databinding.observable.ObservableTracker;
+import org.eclipse.core.databinding.observable.Realm;
+import org.eclipse.core.databinding.observable.value.IObservableValue;
+import org.eclipse.core.databinding.observable.value.IValueChangeListener;
+import org.eclipse.core.databinding.observable.value.WritableValue;
+import org.eclipse.core.runtime.Assert;
+
+/**
+ * An immutable {@link IObservableValue}.
+ * 
+ * @see WritableValue
+ */
+public class ConstantObservableValue : IObservableValue {
+    final Realm realm;
+    final Object value;
+    final Object type;
+
+    /**
+     * Construct a constant value of the given type, in the default realm.
+     * 
+     * @param value
+     *            immutable value
+     * @param type
+     *            type
+     */
+    public this(Object value, Object type) {
+        this(Realm.getDefault(), value, type);
+    }
+
+    /**
+     * Construct a constant value of the given type, in the given realm.
+     * 
+     * @param realm
+     *            Realm
+     * @param value
+     *            immutable value
+     * @param type
+     *            type
+     */
+    public this(Realm realm, Object value, Object type) {
+        Assert.isNotNull(realm, "Realm cannot be null"); //$NON-NLS-1$
+        this.realm = realm;
+        this.value = value;
+        this.type = type;
+    }
+
+    public Object getValueType() {
+        return type;
+    }
+
+    public Object getValue() {
+        ObservableTracker.getterCalled(this);
+        return value;
+    }
+
+    public void setValue(Object value) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void addValueChangeListener(IValueChangeListener listener) {
+        // ignore
+    }
+
+    public void removeValueChangeListener(IValueChangeListener listener) {
+        // ignore
+    }
+
+    public void addChangeListener(IChangeListener listener) {
+        // ignore
+    }
+
+    public void addStaleListener(IStaleListener listener) {
+        // ignore
+    }
+
+    public void dispose() {
+        // nothing to dispose
+    }
+
+    public Realm getRealm() {
+        return realm;
+    }
+
+    public bool isStale() {
+        return false;
+    }
+
+    public void removeChangeListener(IChangeListener listener) {
+        // ignore
+    }
+
+    public void removeStaleListener(IStaleListener listener) {
+        // ignore
+    }
+}