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 043package org.jfree.ui; 044 045import java.awt.event.FocusEvent; 046import java.awt.event.FocusListener; 047import 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 */ 054public 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}