EDIT

/*******************************************************************************

 * Copyright (c) 2000, 2010 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

 *******************************************************************************/

package org.eclipse.draw2d.internal;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

public class MultiValueMap {

	private HashMap map = new HashMap();

	public ArrayList get(Object key) {

		Object value = map.get(key);

		if (value == null)

			return null;

		if (value instanceof ArrayList)

			return (ArrayList) value;

		ArrayList v = new ArrayList(1);

		v.add(value);

		return v;

	}

	public void put(Object key, Object value) {

		Object existingValues = map.get(key);

		if (existingValues == null) {

			map.put(key, value);

			return;

		}

		if (existingValues instanceof ArrayList) {

			ArrayList v = (ArrayList) existingValues;

			if (!v.contains(value))

				v.add(value);

			return;

		}

		if (existingValues != value) {

			ArrayList v = new ArrayList(2);

			v.add(existingValues);

			v.add(value);

			map.put(key, v);

		}

	}

	public int remove(Object key, Object value) {

		Object existingValues = map.get(key);

		if (existingValues != null) {

			if (existingValues instanceof ArrayList) {

				ArrayList v = (ArrayList) existingValues;

				int result = v.indexOf(value);

				if (result == -1)

					return -1;

				v.remove(result);

				if (v.isEmpty())

					map.remove(key);

				return result;

			}

			if (map.remove(key) != null)

				return 0;

		}

		return -1;

	}

	public Object removeValue(Object value) {

		Iterator iter = map.values().iterator();

		Object current;

		while (iter.hasNext()) {

			current = iter.next();

			if (value.equals(current)) {

				iter.remove();

				return value;

			} else if (current instanceof List) {

				if (((List) current).remove(value)) {

					if (((List) current).isEmpty())

						iter.remove();

					return value;

				}

			}

		}

		return null;

	}

	public int size() {

		return map.size();

	}

}