Source for javax.swing.InputMap

   1: /* InputMap.java --
   2:    Copyright (C) 2002, 2004, 2006, Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package javax.swing;
  39: 
  40: import java.io.Serializable;
  41: import java.util.Arrays;
  42: import java.util.HashMap;
  43: import java.util.HashSet;
  44: import java.util.Map;
  45: import java.util.Set;
  46: 
  47: /**
  48:  * Maps {@link KeyStroke}s to arbitrary objects, usually Strings. This
  49:  * is used in combination with {@link ActionMap}s.
  50:  *
  51:  * If a component receives an input event, this is looked up in
  52:  * the component's <code>InputMap</code>. The result is an object which
  53:  * serves as a key to the component's <code>ActionMap</code>. Finally
  54:  * the <code>Action</code> that is stored is executed.
  55:  *
  56:  * @author Andrew Selkirk
  57:  * @author Michael Koch
  58:  *
  59:  * @since 1.3
  60:  */
  61: public class InputMap
  62:   implements Serializable
  63: {
  64:   private static final long serialVersionUID = -5429059542008604257L;
  65: 
  66:   /**
  67:    * Storage for the KeyStroke --> Object mappings.
  68:    */
  69:   private Map inputMap;
  70: 
  71:   /**
  72:    * An optional parent map.
  73:    */
  74:   private InputMap parent;
  75: 
  76:   /**
  77:    * Creates a new <code>InputMap</code> instance.  This default instance
  78:    * contains no mappings and has no parent.
  79:    */
  80:   public InputMap()
  81:   {
  82:     // nothing to do
  83:   }
  84: 
  85:   /**
  86:    * Returns the binding for the specified keystroke, if there is one.
  87:    *
  88:    * @param keystroke the key of the entry (<code>null</code> is ignored).
  89:    *
  90:    * @return The binding associated with the specified keystroke (or 
  91:    *     <code>null</code>).
  92:    */
  93:   public Object get(KeyStroke keystroke)
  94:   {
  95:     Object result = null;
  96:     if (inputMap != null)
  97:       result = inputMap.get(keystroke);
  98: 
  99:     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: }