001/* InputMap.java -- 002 Copyright (C) 2002, 2004, 2006, Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package javax.swing; 039 040import java.io.Serializable; 041import java.util.Arrays; 042import java.util.HashMap; 043import java.util.HashSet; 044import java.util.Map; 045import java.util.Set; 046 047/** 048 * Maps {@link KeyStroke}s to arbitrary objects, usually Strings. This 049 * is used in combination with {@link ActionMap}s. 050 * 051 * If a component receives an input event, this is looked up in 052 * the component's <code>InputMap</code>. The result is an object which 053 * serves as a key to the component's <code>ActionMap</code>. Finally 054 * the <code>Action</code> that is stored is executed. 055 * 056 * @author Andrew Selkirk 057 * @author Michael Koch 058 * 059 * @since 1.3 060 */ 061public class InputMap 062 implements Serializable 063{ 064 private static final long serialVersionUID = -5429059542008604257L; 065 066 /** 067 * Storage for the KeyStroke --> Object mappings. 068 */ 069 private Map inputMap; 070 071 /** 072 * An optional parent map. 073 */ 074 private InputMap parent; 075 076 /** 077 * Creates a new <code>InputMap</code> instance. This default instance 078 * contains no mappings and has no parent. 079 */ 080 public InputMap() 081 { 082 // nothing to do 083 } 084 085 /** 086 * Returns the binding for the specified keystroke, if there is one. 087 * 088 * @param keystroke the key of the entry (<code>null</code> is ignored). 089 * 090 * @return The binding associated with the specified keystroke (or 091 * <code>null</code>). 092 */ 093 public Object get(KeyStroke keystroke) 094 { 095 Object result = null; 096 if (inputMap != null) 097 result = inputMap.get(keystroke); 098 099 if (result == null && parent != null) 100 result = parent.get(keystroke); 101 return result; 102 } 103 104 /** 105 * Puts a new entry into the <code>InputMap</code>. If 106 * <code>actionMapKey</code> is <code>null</code> any existing entry will be 107 * removed. 108 * 109 * @param keystroke the keystroke for the entry (<code>null</code> is 110 * ignored). 111 * @param actionMapKey the action (<code>null</code> permitted). 112 */ 113 public void put(KeyStroke keystroke, Object actionMapKey) 114 { 115 if (keystroke == null) 116 return; 117 if (inputMap == null) 118 inputMap = new HashMap(); 119 if (actionMapKey == null) 120 inputMap.remove(keystroke); 121 else 122 inputMap.put(keystroke, actionMapKey); 123 } 124 125 /** 126 * Removes an entry from this <code>InputMap</code>. Note that this will 127 * not remove any entry from the parent map, if there is one. 128 * 129 * @param keystroke the key of the entry to remove (<code>null</code> is 130 * ignored). 131 */ 132 public void remove(KeyStroke keystroke) 133 { 134 if (inputMap != null) 135 inputMap.remove(keystroke); 136 } 137 138 /** 139 * Returns the parent of this <code>InputMap</code>. The default value 140 * is <code>null</code>. 141 * 142 * @return The parent map (possibly <code>null</code>). 143 * 144 * @see #setParent(InputMap) 145 */ 146 public InputMap getParent() 147 { 148 return parent; 149 } 150 151 /** 152 * Sets a parent for this <code>InputMap</code>. If a parent is specified, 153 * the {@link #get(KeyStroke)} method will look in the parent if it cannot 154 * find an entry in this map. 155 * 156 * @param parentMap the new parent (<code>null</code> permitted). 157 * 158 * @see #getParent() 159 */ 160 public void setParent(InputMap parentMap) 161 { 162 parent = parentMap; 163 } 164 165 /** 166 * Returns the number of entries in this <code>InputMap</code>. This count 167 * does not include any entries from the parent map, if there is one. 168 * 169 * @return The number of entries. 170 */ 171 public int size() 172 { 173 int result = 0; 174 if (inputMap != null) 175 result = inputMap.size(); 176 return result; 177 } 178 179 /** 180 * Clears the entries from this <code>InputMap</code>. The parent map, if 181 * there is one, is not cleared. 182 */ 183 public void clear() 184 { 185 if (inputMap != null) 186 inputMap.clear(); 187 } 188 189 /** 190 * Returns all keys of entries in this <code>InputMap</code>. This does not 191 * include keys defined in the parent, if there is one (use the 192 * {@link #allKeys()} method for that case). 193 * <br><br> 194 * Following the behaviour of the reference implementation, this method will 195 * return <code>null</code> when no entries have been added to the map, 196 * and a zero length array if entries have been added but subsequently 197 * removed (or cleared) from the map. 198 * 199 * @return An array of keys (may be <code>null</code> or have zero length). 200 */ 201 public KeyStroke[] keys() 202 { 203 if (inputMap != null) 204 { 205 KeyStroke[] array = new KeyStroke[size()]; 206 return (KeyStroke[]) inputMap.keySet().toArray(array); 207 } 208 return null; 209 } 210 211 /** 212 * Returns all keys of entries in this <code>InputMap</code> and all its 213 * parents. 214 * 215 * @return An array of keys (may be <code>null</code> or have zero length). 216 */ 217 public KeyStroke[] allKeys() 218 { 219 Set set = new HashSet(); 220 221 if (parent != null) 222 { 223 Object[] parentKeys = parent.allKeys(); 224 if (parentKeys != null) 225 set.addAll(Arrays.asList(parentKeys)); 226 } 227 if (inputMap != null) 228 set.addAll(inputMap.keySet()); 229 if (set.size() == 0) 230 return null; 231 KeyStroke[] array = new KeyStroke[set.size()]; 232 return (KeyStroke[]) set.toArray(array); 233 } 234 235}