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 043package org.jfree.ui; 044 045import java.awt.event.FocusEvent; 046import java.awt.event.FocusListener; 047 048import 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 */ 055public 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}