001 /*
002 * $Id: EnumComboBoxModel.java 2794 2008-03-05 02:46:37Z 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.util.ArrayList;
024 import java.util.EnumSet;
025 import java.util.HashMap;
026 import java.util.Iterator;
027 import java.util.Map;
028
029 /**
030 * <p>
031 * A ComboBoxModel implementation that safely wraps an Enum. It allows the
032 * developer to directly use an enum as their model for a combobox without any
033 * extra work, though the display can can be further customized.
034 * </p>
035 *
036 * <h4>Simple Usage</h4>
037 *
038 * <p>
039 * The simplest usage is to wrap an <code>enum</code> inside the
040 * <code>EnumComboBoxModel</code> and then set it as the model on the combo
041 * box. The combo box will then appear on screen with each value in the
042 * <code>enum</code> as a value in the combobox.
043 * </p>
044 * <p>
045 * ex:
046 * </p>
047 *
048 * <pre><code>
049 * enum MyEnum { GoodStuff, BadStuff };
050 * ...
051 * JComboBox combo = new JComboBox();
052 * combo.setModel(new EnumComboBoxModel(MyEnum.class));
053 * </code></pre>
054 *
055 * <h4>Type safe access</h4>
056 * <p>
057 * By using generics and co-variant types you can make accessing elements from
058 * the model be completely typesafe. ex:
059 * </p>
060 *
061 * <pre><code>
062 * EnumComboBoxModel<MyEnum> enumModel = new EnumComboBoxModel<MyEnum1>(
063 * MyEnum1.class);
064 *
065 * MyEnum first = enumModel.getElement(0);
066 *
067 * MyEnum selected = enumModel.getSelectedItem();
068 * </code></pre>
069 *
070 * <h4>Advanced Usage</h4>
071 * <p>
072 * Since the exact <code>toString()</code> value of each enum constant may not
073 * be exactly what you want on screen (the values won't have spaces, for
074 * example) you can override to toString() method on the values when you declare
075 * your enum. Thus the display value is localized to the enum and not in your
076 * GUI code. ex:
077 *
078 * <pre><code>
079 * private enum MyEnum {GoodStuff, BadStuff;
080 * public String toString() {
081 * switch(this) {
082 * case GoodStuff: return "Some Good Stuff";
083 * case BadStuff: return "Some Bad Stuff";
084 * }
085 * return "ERROR";
086 * }
087 * };
088 * </code></pre>
089 *
090 * Note: if more than one enum constant returns the same {@code String} via
091 * {@code toString()}, this model will throw an exception on creation.
092 *
093 * @author joshy
094 * @author Karl Schaefer
095 */
096 public class EnumComboBoxModel<E extends Enum<E>> extends ListComboBoxModel<E> {
097 private static final long serialVersionUID = 2176566393195371004L;
098
099 private final Map<String, E> valueMap;
100 private final Class<E> enumClass;
101
102 /**
103 * Creates an {@code EnumComboBoxModel} for the enum represent by the
104 * {@code Class} {@code en}.
105 *
106 * @param en
107 * the enum class type
108 * @throws IllegalArgumentException
109 * if the {@code Enum.toString} returns the same value for more
110 * than one constant
111 */
112 public EnumComboBoxModel(Class<E> en) {
113 super(new ArrayList<E>(EnumSet.allOf(en)));
114
115 //we could size these, probably not worth it; enums are usually small
116 valueMap = new HashMap<String, E>();
117 enumClass = en;
118
119 Iterator<E> iter = data.iterator();
120
121 while (iter.hasNext()) {
122 E element = iter.next();
123 String s = element.toString();
124
125 if (valueMap.containsKey(s)) {
126 throw new IllegalArgumentException(
127 "multiple constants map to one string value");
128 }
129
130 valueMap.put(s, element);
131 }
132 }
133
134 /**
135 * {@inheritDoc}
136 */
137 @SuppressWarnings("unchecked")
138 public void setSelectedItem(Object anItem) {
139 E input = null;
140
141 if (enumClass.isInstance(anItem)) {
142 input = (E) anItem;
143 } else {
144 input = valueMap.get(anItem);
145 }
146
147 if (input != null || anItem == null) {
148 selected = input;
149 }
150
151 this.fireContentsChanged(this, 0, getSize());
152 }
153
154 /*
155 public static void main(String[] args) {
156 JFrame frame = new JFrame();
157 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
158 frame.setLayout(new BoxLayout(frame.getContentPane(),BoxLayout.Y_AXIS));
159
160
161 JComboBox combo1 = new JComboBox();
162 combo1.setModel(new EnumComboBoxModel(MyEnum1.class));
163 frame.add(combo1);
164
165 JComboBox combo2 = new JComboBox();
166 combo2.setModel(new EnumComboBoxModel(MyEnum2.class));
167 frame.add(combo2);
168
169 EnumComboBoxModel<MyEnum1> enumModel = new EnumComboBoxModel<MyEnum1>(MyEnum1.class);
170 JComboBox combo3 = new JComboBox();
171 combo3.setModel(enumModel);
172 frame.add(combo3);
173
174 MyEnum1 selected = enumModel.getSelectedItem();
175
176 //uncomment to see the ClassCastException
177 // enumModel.setSelectedItem("Die clown");
178
179 frame.pack();
180 frame.setVisible(true);
181 }
182
183 private enum MyEnum1 {GoodStuff, BadStuff};
184 private enum MyEnum2 {GoodStuff, BadStuff;
185 public String toString() {
186 switch(this) {
187 case GoodStuff: return "Some Good Stuff";
188 case BadStuff: return "Some Bad Stuff";
189 }
190 return "ERROR";
191 }
192 };
193 */
194
195 }