--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.base/src/com/sun/max/collect/IdentityHashMapping.java	Sat Dec 17 19:59:18 2011 +0100
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.sun.max.collect;
+
+import java.util.*;
+
+/**
+ */
+public class IdentityHashMapping<K, V> implements Mapping<K, V> {
+
+    private final Map<K, V> delegate;
+
+    public IdentityHashMapping() {
+        delegate = new IdentityHashMap<K, V>();
+    }
+
+    public IdentityHashMapping(int expectedMaxSize) {
+        delegate = new IdentityHashMap<K, V>(expectedMaxSize);
+    }
+
+    public synchronized V put(K key, V value) {
+        return delegate.put(key, value);
+    }
+
+    public synchronized V get(K key) {
+        final V value = delegate.get(key);
+        return value;
+    }
+
+    public synchronized boolean containsKey(K key) {
+        return delegate.containsKey(key);
+    }
+
+    public int length() {
+        return delegate.size();
+    }
+
+    public void clear() {
+        delegate.clear();
+    }
+
+    public V remove(K key) {
+        return delegate.remove(key);
+    }
+
+    public IterableWithLength<K> keys() {
+        return new IterableWithLength<K>() {
+
+            public int size() {
+                return delegate.size();
+            }
+
+            public Iterator<K> iterator() {
+                return delegate.keySet().iterator();
+            }
+        };
+    }
+
+    public IterableWithLength<V> values() {
+        return new IterableWithLength<V>() {
+
+            public int size() {
+                return delegate.size();
+            }
+
+            public Iterator<V> iterator() {
+                return delegate.values().iterator();
+            }
+        };
+    }
+
+}