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 1.5 2005/10/18 13:18:34 mungady 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:
048: import javax.swing.text.JTextComponent;
049:
050: /**
051: * An observer that selects all the text when a field gains the focus.
052: *
053: * @author Thomas Morgner
054: */
055: public final class JTextObserver implements FocusListener {
056:
057: /** The singleton instance. */
058: private static JTextObserver singleton;
059:
060: /**
061: * Creates a new instance.
062: */
063: private JTextObserver() {
064: // nothing required
065: }
066:
067: /**
068: * Returns the single instance.
069: *
070: * @return The single instance.
071: */
072: public static JTextObserver getInstance() {
073: if (singleton == null) {
074: singleton = new JTextObserver();
075: }
076: return singleton;
077: }
078:
079: /**
080: * Selects all the text when a field gains the focus.
081: *
082: * @param e the focus event.
083: */
084: public void focusGained(final FocusEvent e) {
085: if (e.getSource() instanceof JTextComponent) {
086: final JTextComponent tex = (JTextComponent) e.getSource();
087: tex.selectAll();
088: }
089: }
090:
091: /**
092: * Deselects the text when a field loses the focus.
093: *
094: * @param e the event.
095: */
096: public void focusLost(final FocusEvent e) {
097: if (e.getSource() instanceof JTextComponent) {
098: final JTextComponent tex = (JTextComponent) e.getSource();
099: tex.select(0, 0);
100: }
101: }
102:
103: /**
104: * Adds this instance as a listener for the specified text component.
105: *
106: * @param t the text component.
107: */
108: public static void addTextComponent(final JTextComponent t) {
109: if (singleton == null) {
110: singleton = new JTextObserver();
111: }
112: t.addFocusListener(singleton);
113: }
114:
115: /**
116: * Removes this instance as a listener for the specified text component.
117: *
118: * @param t the text component.
119: */
120: public static void removeTextComponent(final JTextComponent t) {
121: if (singleton == null) {
122: singleton = new JTextObserver();
123: }
124: t.removeFocusListener(singleton);
125: }
126:
127: }
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