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

  * Copyright (c) 2008-2009 SWTBot Committers 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:

  *     Ketan Padegaonkar - initial API and implementation

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

 package org.eclipse.swtbot.swt.finder.utils;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.LinkedHashSet;

 import java.util.Set;

 /**

  * Maps a key to a collection of values. The values are maintained in a set that gurantees order, adding the same value twice for the same key will have no effect.

  *

  * @author Ketan Padegaonkar <KetanPadegaonkar [at] gmail [dot] com>

  * @version $Id$

  * @noinstantiate This class is not intended to be instantiated by clients.

  * @noextend This class is not intended to be subclassed by clients.

  */

 public class MultiValueMap<K, V> {

         private HashMap<K, LinkedHashSet<V>>        map;

         public MultiValueMap() {

                 map = new HashMap<K, LinkedHashSet<V>>();

         }

         public void put(K k, V v) {

                 LinkedHashSet<V> collection = map.get(k);

                 if (collection == null) {

                         collection = new LinkedHashSet<V>();

                         map.put(k, collection);

                 }

                 collection.add(v);

         }

         public Collection<V> getCollection(K k) {

                 LinkedHashSet<V> result = map.get(k);

                 if (result != null)

                         return result;

                 return Collections.emptySet();

         }

         public Set<K> keySet() {

                 return map.keySet();

         }

 }