/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package com.nokia.carbide.internal.cpp.epoc.engine.model;

import java.util.AbstractMap;

import java.util.IdentityHashMap;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.Map;

import java.util.Set;

public class OrderedObjectMap<K,V> extends AbstractMap<K,V> {

	IdentityHashMap<K, V> identityMap;

	LinkedList<K> ordering;

	public OrderedObjectMap() {

		this.identityMap = new IdentityHashMap<K, V>();

		this.ordering = new LinkedList<K>();

	}

	@Override

	public Set entrySet() {

		return identityMap.entrySet();

	}

	@Override

	public V put(K key, V value) {

		V orig = identityMap.put(key, value);

		if (orig == null) {

			ordering.add(key);

		}

		return orig;

	}

	@Override

	public V remove(Object key) {

		ordering.remove(key);

		return super.remove(key);

	}

	/**

	 * This method returns an iterator over the entries in

	 * insertion order.

	 * @return

	 */

	public Iterator<Map.Entry<K, V>> orderedIterator() {

		return new Iterator<Entry<K,V>>() {

			Iterator<K> listIterator = ordering.iterator();

			K lastKey = null;

			public boolean hasNext() {

				return listIterator.hasNext();

			}

			public java.util.Map.Entry<K, V> next() {

				lastKey = listIterator.next();

				Entry<K,V> entry = new Entry<K,V>() {

					public K getKey() {

						return lastKey;

					}

					public V getValue() {

						return identityMap.get(lastKey);

					}

					public V setValue(V value) {

						return identityMap.put(lastKey, value);

					}

				};

				return entry;

			}

			public void remove() {

				listIterator.remove();

				identityMap.remove(lastKey);

			}

		};

	}

	public Iterator<K> orderedKeyIterator() {

		return ordering.iterator();

	}

}