001 /*
002 * $Id: ListComboBoxModel.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.awt.event.ActionListener;
025 import java.util.List;
026
027 import javax.swing.AbstractListModel;
028 import javax.swing.ComboBoxModel;
029
030 /**
031 * A {@code ComboBoxModel} for {@code List}s.
032 *
033 * @param <E> the type of elements maintained by the list backing this model
034 *
035 * @author jm158417
036 * @author Karl George Schaefer
037 */
038 public class ListComboBoxModel<E> extends AbstractListModel implements ComboBoxModel, ActionListener {
039 /**
040 * A key used to notify the model that the backing {@code List} has changed.
041 */
042 public static final String UPDATE = "update";
043
044 /**
045 * A reference to the list backing this model.
046 * <p>
047 * This model does <b>not</b> make a copy of the list, so any changes in
048 * the list without synchronizing the model may have drastic effects.
049 */
050 protected final List<E> data;
051
052 /**
053 * The currently selected item.
054 */
055 protected E selected;
056
057 /**
058 * Creates a {@code ListComboBoxModel} backed by the supplied {@code list}.
059 *
060 * @param list
061 * the list backing this model
062 * @throws NullPointerException
063 * if {@code list} is {@code null}
064 */
065 public ListComboBoxModel(List<E> list) {
066 this.data = list;
067
068 if(list.size() > 0) {
069 selected = list.get(0);
070 }
071 }
072
073 /**
074 * Set the selected item. The implementation of this method should notify
075 * all registered {@code ListDataListener}s that the contents have changed.
076 *
077 * @param item
078 * the list object to select or {@code null} to clear the
079 * selection
080 * @throws ClassCastException
081 * if {@code item} is not of type {@code E}
082 */
083 @SuppressWarnings("unchecked")
084 public void setSelectedItem(Object item) {
085 if ((selected != null && !selected.equals(item))
086 || selected == null && item != null) {
087 selected = (E) item;
088 fireContentsChanged(this, -1, -1);
089 }
090 }
091
092 /**
093 * {@inheritDoc}
094 */
095 public E getSelectedItem() {
096 return this.selected;
097 }
098
099 /**
100 * {@inheritDoc}
101 */
102 public E getElementAt(int index) {
103 return data.get(index);
104 }
105
106 /**
107 * {@inheritDoc}
108 */
109 public int getSize() {
110 return data.size();
111 }
112
113 /**
114 * {@inheritDoc}
115 */
116 public void actionPerformed(ActionEvent evt) {
117 if(evt.getActionCommand().equals(UPDATE)) {
118 this.fireContentsChanged(this, 0, getSize() - 1);
119 }
120 }
121 }