001 /* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ------------------
028 * JTextObserver.java
029 * ------------------
030 * (C) Copyright 2004, by Thomas Morgner and Contributors.
031 *
032 * Original Author: Thomas Morgner;
033 * Contributor(s): David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: JTextObserver.java,v 1.6 2007/11/02 17:50:36 taqua Exp $
036 *
037 * Changes
038 * -------
039 * 07-Jun-2004 : Added JCommon header (DG);
040 *
041 */
042
043 package org.jfree.ui;
044
045 import java.awt.event.FocusEvent;
046 import java.awt.event.FocusListener;
047 import javax.swing.text.JTextComponent;
048
049 /**
050 * An observer that selects all the text when a field gains the focus.
051 *
052 * @author Thomas Morgner
053 */
054 public final class JTextObserver implements FocusListener {
055
056 /** The singleton instance. */
057 private static JTextObserver singleton;
058
059 /**
060 * Creates a new instance.
061 */
062 private JTextObserver() {
063 // nothing required
064 }
065
066 /**
067 * Returns the single instance.
068 *
069 * @return The single instance.
070 */
071 public static JTextObserver getInstance() {
072 if (singleton == null) {
073 singleton = new JTextObserver();
074 }
075 return singleton;
076 }
077
078 /**
079 * Selects all the text when a field gains the focus.
080 *
081 * @param e the focus event.
082 */
083 public void focusGained(final FocusEvent e) {
084 if (e.getSource() instanceof JTextComponent) {
085 final JTextComponent tex = (JTextComponent) e.getSource();
086 tex.selectAll();
087 }
088 }
089
090 /**
091 * Deselects the text when a field loses the focus.
092 *
093 * @param e the event.
094 */
095 public void focusLost(final FocusEvent e) {
096 if (e.getSource() instanceof JTextComponent) {
097 final JTextComponent tex = (JTextComponent) e.getSource();
098 tex.select(0, 0);
099 }
100 }
101
102 /**
103 * Adds this instance as a listener for the specified text component.
104 *
105 * @param t the text component.
106 */
107 public static void addTextComponent(final JTextComponent t) {
108 if (singleton == null) {
109 singleton = new JTextObserver();
110 }
111 t.addFocusListener(singleton);
112 }
113
114 /**
115 * Removes this instance as a listener for the specified text component.
116 *
117 * @param t the text component.
118 */
119 public static void removeTextComponent(final JTextComponent t) {
120 if (singleton == null) {
121 singleton = new JTextObserver();
122 }
123 t.removeFocusListener(singleton);
124 }
125
126 }