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1: /* DefaultSingleSelectionModel.java -- 2: Copyright (C) 2002, 2004, 2006, Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package javax.swing; 40: 41: import java.io.Serializable; 42: import java.util.EventListener; 43: 44: import javax.swing.event.ChangeEvent; 45: import javax.swing.event.ChangeListener; 46: import javax.swing.event.EventListenerList; 47: 48: /** 49: * The default implementation of {@link SingleSelectionModel}, used in 50: * {@link JTabbedPane}, {@link JMenuBar} and {@link JPopupMenu}. 51: * 52: * @author Andrew Selkirk 53: */ 54: public class DefaultSingleSelectionModel 55: implements SingleSelectionModel, Serializable 56: { 57: private static final long serialVersionUID = 3676229404753786004L; 58: 59: /** 60: * changeEvent 61: */ 62: protected transient ChangeEvent changeEvent; 63: 64: /** 65: * listenerList 66: */ 67: protected EventListenerList listenerList = new EventListenerList(); 68: 69: /** 70: * The selected index (or -1 for no selection). 71: */ 72: private int index = -1; 73: 74: /** 75: * Creates a new <code>DefaultSingleSelectionModel</code> with no current 76: * selection. 77: */ 78: public DefaultSingleSelectionModel() 79: { 80: // Do nothing. 81: } 82: 83: /** 84: * Returns the selected index or <code>-1</code> if there is no selection. 85: * 86: * @return The selected index. 87: * 88: * @see #setSelectedIndex(int) 89: */ 90: public int getSelectedIndex() 91: { 92: return index; 93: } 94: 95: /** 96: * Sets the selected index and, if this is different to the previous 97: * selection, sends a {@link ChangeEvent} to all registered listeners. 98: * 99: * @param index the index (use <code>-1</code> to represent no selection). 100: * 101: * @see #getSelectedIndex() 102: * @see #clearSelection 103: */ 104: public void setSelectedIndex(int index) 105: { 106: if (this.index != index) 107: { 108: this.index = index; 109: fireStateChanged(); 110: } 111: } 112: 113: /** 114: * Clears the selection by setting the selected index to <code>-1</code> and 115: * sends a {@link ChangeEvent} to all registered listeners. If the selected 116: * index is already <code>-1</code>, this method does nothing. 117: */ 118: public void clearSelection() 119: { 120: setSelectedIndex(-1); 121: } 122: 123: /** 124: * Returns <code>true</code> if there is a selection, and <code>false</code> 125: * otherwise. 126: * 127: * @return A boolean. 128: */ 129: public boolean isSelected() 130: { 131: return index != -1; 132: } 133: 134: /** 135: * Registers a listener to receive {@link ChangeEvent} notifications from 136: * this model whenever the selected index changes. 137: * 138: * @param listener the listener to add. 139: */ 140: public void addChangeListener(ChangeListener listener) 141: { 142: listenerList.add(ChangeListener.class, listener); 143: } 144: 145: /** 146: * Deregisters a listener so that it no longer receives {@link ChangeEvent} 147: * notifications from this model. 148: * 149: * @param listener the listener to remove. 150: */ 151: public void removeChangeListener(ChangeListener listener) 152: { 153: listenerList.remove(ChangeListener.class, listener); 154: } 155: 156: /** 157: * fireStateChanged 158: */ 159: protected void fireStateChanged() 160: { 161: if (changeEvent == null) 162: changeEvent = new ChangeEvent(this); 163: ChangeListener[] listeners = getChangeListeners(); 164: for (int i = 0; i < listeners.length; i++) 165: listeners[i].stateChanged(changeEvent); 166: } 167: 168: /** 169: * getListeners 170: * 171: * @param listenerClass the type fo listener 172: * 173: * @return an array of listeners 174: * 175: * @since 1.3 176: */ 177: public <T extends EventListener> T[] getListeners(Class<T> listenerClass) 178: { 179: return listenerList.getListeners(listenerClass); 180: } 181: 182: /** 183: * getChangeListeners 184: * 185: * @since 1.4 186: */ 187: public ChangeListener[] getChangeListeners() 188: { 189: return (ChangeListener[]) getListeners(ChangeListener.class); 190: } 191: }