001 /* FocusEvent.java -- generated for a focus change 002 Copyright (C) 1999, 2002, 2005 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.awt.event; 040 041 import java.awt.Component; 042 043 /** 044 * This class represents an event generated when a focus change occurs for a 045 * component. There are both temporary changes, such as when focus is stolen 046 * during a sroll then returned, and permanent changes, such as when the user 047 * TABs through focusable components. 048 * 049 * @author Aaron M. Renn (arenn@urbanophile.com) 050 * @see FocusAdapter 051 * @see FocusListener 052 * @since 1.1 053 * @status updated to 1.4 054 */ 055 public class FocusEvent extends ComponentEvent 056 { 057 /** 058 * Compatible with JDK 1.1+. 059 */ 060 private static final long serialVersionUID = 523753786457416396L; 061 062 /** This is the first id in the range of ids used by this class. */ 063 public static final int FOCUS_FIRST = 1004; 064 065 /** This is the last id in the range of ids used by this class. */ 066 public static final int FOCUS_LAST = 1005; 067 068 /** This is the event id for a focus gained event. */ 069 public static final int FOCUS_GAINED = 1004; 070 071 /** This is the event id for a focus lost event. */ 072 public static final int FOCUS_LOST = 1005; 073 074 /** 075 * Indicates whether or not the focus change is temporary. 076 * 077 * @see #isTemporary() 078 * @serial true if the focus change is temporary 079 */ 080 private final boolean temporary; 081 082 /** 083 * The other component which is giving up or stealing focus from this 084 * component, if known. 085 * 086 * @see #getOppositeComponent() 087 * @serial the component with the opposite focus event, or null 088 * @since 1.4 089 */ 090 private final Component opposite; 091 092 /** 093 * Initializes a new instance of <code>FocusEvent</code> with the 094 * specified source, id, temporary status, and opposite counterpart. Note 095 * that an invalid id leads to unspecified results. 096 * 097 * @param source the component that is gaining or losing focus 098 * @param id the event id 099 * @param temporary true if the focus change is temporary 100 * @param opposite the component receiving the opposite focus event, or null 101 * @throws IllegalArgumentException if source is null 102 */ 103 public FocusEvent(Component source, int id, boolean temporary, 104 Component opposite) 105 { 106 super(source, id); 107 this.temporary = temporary; 108 this.opposite = opposite; 109 } 110 111 /** 112 * Initializes a new instance of <code>FocusEvent</code> with the 113 * specified source, id, and temporary status. Note that an invalid id 114 * leads to unspecified results. 115 * 116 * @param source the component that is gaining or losing focus 117 * @param id the event id 118 * @param temporary true if the focus change is temporary 119 * @throws IllegalArgumentException if source is null 120 */ 121 public FocusEvent(Component source, int id, boolean temporary) 122 { 123 this(source, id, temporary, null); 124 } 125 126 /** 127 * Initializes a new instance of <code>FocusEvent</code> with the 128 * specified source and id. Note that an invalid id leads to unspecified 129 * results. 130 * 131 * @param source the component that is gaining or losing focus 132 * @param id the event id 133 * @throws IllegalArgumentException if source is null 134 */ 135 public FocusEvent(Component source, int id) 136 { 137 this(source, id, false, null); 138 } 139 140 /** 141 * This method tests whether or not the focus change is temporary or 142 * permanent. 143 * 144 * @return true if the focus change is temporary 145 */ 146 public boolean isTemporary() 147 { 148 return temporary; 149 } 150 151 /** 152 * Returns the component which received the opposite focus event. If this 153 * component gained focus, the opposite lost focus; likewise if this 154 * component is giving up focus, the opposite is gaining it. If this 155 * information is unknown, perhaps because the opposite is a native 156 * application, this returns null. 157 * 158 * @return the component with the focus opposite, or null 159 * @since 1.4 160 */ 161 public Component getOppositeComponent() 162 { 163 return opposite; 164 } 165 166 /** 167 * Returns a string identifying this event. This is formatted as: 168 * <code>(getID() == FOCUS_GAINED ? "FOCUS_GAINED" : "FOCUS_LOST") 169 * + (isTemporary() ? ",temporary," : ",permanent,") + "opposite=" 170 * + getOppositeComponent()</code>. 171 * 172 * @return a string identifying this event 173 */ 174 public String paramString() 175 { 176 return (id == FOCUS_GAINED ? "FOCUS_GAINED" 177 : id == FOCUS_LOST ? "FOCUS_LOST" : "unknown type") 178 + (temporary ? ",temporary,opposite=" : ",permanent,opposite=") 179 + opposite; 180 } 181 } // class FocusEvent