Merging from -r468106:814127 of collections_jdk5_branch - namely where this code was generified; mostly in r738956.

Also see the following revisions:

    ------------------------------------------------------------------------
    r751865 | mbenson | 2009-03-09 15:06:27 -0700 (Mon, 09 Mar 2009) | 1 line
    
    javadoc + extension point
    ------------------------------------------------------------------------
    r740150 | mbenson | 2009-02-02 15:24:00 -0800 (Mon, 02 Feb 2009) | 1 line
    
    make all [collections] maps implement IterableMap
    ------------------------------------------------------------------------


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@815076 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/collections/map/EntrySetToMapIteratorAdapter.java

@@ -0,0 +1,114 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.collections.map;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.collections.MapIterator;
+import org.apache.commons.collections.ResettableIterator;
+
+/**
+ * Adapts a Map entrySet to the MapIterator interface.
+ *
+ * @since Commons Collections 5
+ * @TODO fix version
+ * @version $Revision$ $Date$
+ *
+ * @author Matt Benson
+ */
+public class EntrySetToMapIteratorAdapter<K, V> implements MapIterator<K, V>, ResettableIterator<K> {
+    /** The adapted Map entry Set. */
+    protected Set<Map.Entry<K, V>> entrySet;
+
+    /** The resettable iterator in use. */
+    protected transient Iterator<Map.Entry<K, V>> iterator;
+
+    /** The currently positioned Map entry. */
+    protected transient Map.Entry<K, V> entry;
+
+    /**
+     * Create a new EntrySetToMapIteratorAdapter.
+     */
+    public EntrySetToMapIteratorAdapter(Set<Map.Entry<K, V>> entrySet) {
+        this.entrySet = entrySet;
+        reset();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public K getKey() {
+        return current().getKey();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public V getValue() {
+        return current().getValue();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public V setValue(V value) {
+        return current().setValue(value);
+    };
+
+    /**
+     * {@inheritDoc}
+     */
+    public boolean hasNext() {
+        return iterator.hasNext();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public K next() {
+        entry = iterator.next();
+        return getKey();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public synchronized void reset() {
+        iterator = entrySet.iterator();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public void remove() {
+        iterator.remove();
+        entry = null;
+    }
+
+    /**
+     * Get the currently active entry.
+     * @return Map.Entry<K, V>
+     */
+    protected synchronized Map.Entry<K, V> current() { 
+        if (entry == null) {
+            throw new IllegalStateException();
+        }
+        return entry;
+    }
+}