001 /*
002 * $Id: MapComboBoxModel.java 3374 2009-07-01 14:36:43Z kschaefe $
003 *
004 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
005 * Santa Clara, California 95054, U.S.A. All rights reserved.
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * You should have received a copy of the GNU Lesser General Public
018 * License along with this library; if not, write to the Free Software
019 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
020 */
021 package org.jdesktop.swingx.combobox;
022
023 import java.awt.event.ActionEvent;
024 import java.util.ArrayList;
025 import java.util.HashMap;
026 import java.util.List;
027 import java.util.Map;
028 import java.util.Set;
029
030 /**
031 * A {@code ComboBoxModel} for {@code Map}s. The model will always present a {@code Map}
032 * consistently, once it is instantiated. However, unless the {@code Map} is ordered, as a
033 * {@code java.util.TreeMap} is, the model is not guaranteed to present the maps in a consistent
034 * order between instantiations.
035 *
036 * @author jm158417
037 * @author Karl George Schaefer
038 *
039 * @param <K>
040 * the type of keys maintained by the map backing this model
041 * @param <V>
042 * the type of mapped values
043 */
044 public class MapComboBoxModel<K, V> extends ListComboBoxModel<K> {
045
046 /**
047 * The map backing this model.
048 */
049 protected Map<K, V> map_data;
050
051 /**
052 * Creates an empty model.
053 */
054 public MapComboBoxModel() {
055 this(new HashMap<K, V>());
056 }
057
058 /**
059 * Creates a model backed by the specified map.
060 *
061 * @param map
062 * the map backing this model
063 */
064 public MapComboBoxModel(Map<K, V> map) {
065 super(buildIndex(map));
066
067 this.map_data = map;
068 }
069
070 /**
071 * Builds an index for this model. This method ensures that the map is always presented in a
072 * consistent order.
073 * <p>
074 * This method is called by the constructor and the {@code List} is passed to {@code super}.
075 *
076 * @param <E>
077 * the type of keys for the map
078 * @param map
079 * the map to build an index for
080 * @return a list containing the map keys
081 */
082 private static <E> List<E> buildIndex(Map<E, ?> map) {
083 return new ArrayList<E>(map.keySet());
084 }
085
086 /**
087 * {@inheritDoc}
088 */
089 public int getSize() {
090 return map_data.size();
091 }
092
093 /**
094 * {@inheritDoc}
095 */
096 public void actionPerformed(ActionEvent evt) {
097 //kgs - this code might not be performant with large maps
098 if(evt.getActionCommand().equals(UPDATE)) {
099 //add new keys
100 Set<K> keys = map_data.keySet();
101 keys.removeAll(data);
102 data.addAll(keys);
103
104 //remove dead keys
105 List<K> copy = new ArrayList<K>(data);
106 keys = map_data.keySet();
107 copy.removeAll(keys);
108 data.removeAll(copy);
109
110 fireContentsChanged(this, 0, getSize() - 1);
111 }
112 }
113
114 /**
115 * Selects an item from the model and returns that map value.
116 *
117 * @param selectedItem
118 * the item to select
119 * @return the value for the selected item
120 */
121 public V getValue(Object selectedItem) {
122 return map_data.get(selectedItem);
123 }
124
125 /**
126 * Selects an item from the model and returns that map value.
127 *
128 * @param selectedItem
129 * selects the item at the specified index in this model
130 * @return the value for the item at the selected index
131 */
132 public V getValue(int selectedItem) {
133 return getValue(getElementAt(selectedItem));
134 }
135 }