Source for java.util.EnumMap

   1: /* EnumMap.java - Map where keys are enum constants
   2:    Copyright (C) 2004, 2005, 2007 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: 
  39: package java.util;
  40: 
  41: import java.io.Serializable;
  42: 
  43: /** 
  44:  * @author Tom Tromey (tromey@redhat.com)
  45:  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  46:  * @since 1.5 
  47:  */
  48: 
  49: public class EnumMap<K extends Enum<K>, V>
  50:   extends AbstractMap<K, V>
  51:   implements Cloneable, Serializable
  52: {
  53:   private static final long serialVersionUID = 458661240069192865L;
  54: 
  55:   V[] store;
  56:   int cardinality;
  57:   Class<K> enumClass;
  58: 
  59:   /**
  60:    * The cache for {@link #entrySet()}.
  61:    */
  62:   transient Set<Map.Entry<K, V>> entries;
  63: 
  64:   static final Object emptySlot = new Object();
  65: 
  66:   public EnumMap(Class<K> keyType)
  67:   {
  68:     store = (V[]) new Object[keyType.getEnumConstants().length];
  69:     Arrays.fill(store, emptySlot);
  70:     cardinality = 0;
  71:     enumClass = keyType;
  72:   }
  73: 
  74:   public EnumMap(EnumMap<K, ? extends V> map)
  75:   {
  76:     store = (V[]) map.store.clone();
  77:     cardinality = map.cardinality;
  78:     enumClass = map.enumClass;
  79:   }
  80: 
  81:   public EnumMap(Map<K, ? extends V> map)
  82:   {
  83:     if (map instanceof EnumMap)
  84:       {
  85:     EnumMap<K, ? extends V> other = (EnumMap<K, ? extends V>) map;
  86:     store = (V[]) other.store.clone();
  87:     cardinality = other.cardinality;
  88:     enumClass = other.enumClass;
  89:       }
  90:     else
  91:       {
  92:     for (K key : map.keySet())
  93:       {
  94:         V value = map.get(key);
  95:         if (store == null)
  96:           {
  97:         enumClass = key.getDeclaringClass();
  98:         store = (V[]) new Object[enumClass.getEnumConstants().length];
  99:           }
 100:         int o = key.ordinal();
 101:         if (store[o] == emptySlot)
 102:           ++cardinality;
 103:         store[o] = value;
 104:       }
 105:     // There must be a single element.
 106:     if (store == null)
 107:       throw new IllegalArgumentException("no elements in map");
 108:       }
 109:   }
 110: 
 111:   public int size()
 112:   {
 113:     return cardinality;
 114:   }
 115: 
 116:   public boolean containsValue(Object value)
 117:   {
 118:     for (V i : store)
 119:       {
 120:     if (i != emptySlot && AbstractCollection.equals(i , value))
 121:       return true;
 122:       }
 123:     return false;
 124:   }
 125: 
 126:   public boolean containsKey(Object key)
 127:   {
 128:     if (! (key instanceof Enum))
 129:       return false;
 130:     Enum<K> e = (Enum<K>) key;
 131:     if (e.getDeclaringClass() != enumClass)
 132:       return false;
 133:     return store[e.ordinal()] != emptySlot;
 134:   }
 135: 
 136:   public V get(Object key)
 137:   {
 138:     if (! (key instanceof Enum))
 139:       return null;
 140:     Enum<K> e = (Enum<K>) key;
 141:     if (e.getDeclaringClass() != enumClass)
 142:       return null;
 143:     V o = store[e.ordinal()];
 144:     return o == emptySlot ? null : o;
 145:   }
 146: 
 147:   public V put(K key, V value)
 148:   {
 149:     int o = key.ordinal();
 150:     V result;
 151:     if (store[o] == emptySlot)
 152:       {
 153:     result = null;
 154:     ++cardinality;
 155:       }
 156:     else
 157:       result = store[o];
 158:     store[o] = value;
 159:     return result;
 160:   }
 161: 
 162:   public V remove(Object key)
 163:   {
 164:     if (! (key instanceof Enum))
 165:       return null;
 166:     Enum<K> e = (Enum<K>) key;
 167:     if (e.getDeclaringClass() != enumClass)
 168:       return null;
 169:     V result = store[e.ordinal()];
 170:     if (result == emptySlot)
 171:       result = null;
 172:     else
 173:       --cardinality;
 174:     store[e.ordinal()] = (V) emptySlot;
 175:     return result;
 176:   }
 177: 
 178:   public void putAll(Map<? extends K, ? extends V> map)
 179:   {
 180:     for (K key : map.keySet())
 181:       {
 182:     V value = map.get(key);
 183: 
 184:     int o = key.ordinal();
 185:     if (store[o] == emptySlot)
 186:       ++cardinality;
 187:     store[o] = value;
 188:       }
 189:   }
 190: 
 191:   public void clear()
 192:   {
 193:     Arrays.fill(store, emptySlot);
 194:     cardinality = 0;
 195:   }
 196: 
 197:   public Set<K> keySet()
 198:   {
 199:     if (keys == null)
 200:       {
 201:     keys = new AbstractSet<K>()
 202:     {
 203:       public int size()
 204:       {
 205:         return cardinality;
 206:       }
 207: 
 208:       public Iterator<K> iterator()
 209:       {
 210:         return new Iterator<K>()
 211:         {
 212:           int count = 0;
 213:           int index = -1;
 214: 
 215:           public boolean hasNext()
 216:           {
 217:         return count < cardinality;
 218:           }
 219: 
 220:           public K next()
 221:           {
 222:         ++count;
 223:         for (++index; store[index] == emptySlot; ++index)
 224:           ;
 225:         return enumClass.getEnumConstants()[index];
 226:           }
 227: 
 228:           public void remove()
 229:           {
 230:         --cardinality;
 231:         store[index] = (V) emptySlot;
 232:           }
 233:         };
 234:       }
 235: 
 236:       public void clear()
 237:       {
 238:         EnumMap.this.clear();
 239:       }
 240: 
 241:       public boolean contains(Object o)
 242:       {
 243:         return contains(o);
 244:       }
 245: 
 246:       public boolean remove(Object o)
 247:       {
 248:         return EnumMap.this.remove(o) != null;
 249:       }
 250:     };
 251:       }
 252:     return keys;
 253:   }
 254: 
 255:   public Collection<V> values()
 256:   {
 257:     if (values == null)
 258:       {
 259:     values = new AbstractCollection<V>()
 260:     {
 261:       public int size()
 262:       {
 263:         return cardinality;
 264:       }
 265: 
 266:       public Iterator<V> iterator()
 267:       {
 268:         return new Iterator<V>()
 269:         {
 270:           int count = 0;
 271:           int index = -1;
 272: 
 273:           public boolean hasNext()
 274:           {
 275:         return count < cardinality;
 276:           }
 277: 
 278:           public V next()
 279:           {
 280:         ++count;
 281:         for (++index; store[index] == emptySlot; ++index)
 282:           ;
 283:         return store[index];
 284:           }
 285: 
 286:           public void remove()
 287:           {
 288:         --cardinality;
 289:         store[index] = (V) emptySlot;
 290:           }
 291:         };
 292:       }
 293: 
 294:       public void clear()
 295:       {
 296:         EnumMap.this.clear();
 297:       }
 298:     };
 299:       }
 300:     return values;
 301:   }
 302: 
 303:   public Set<Map.Entry<K, V>> entrySet()
 304:   {
 305:     if (entries == null)
 306:       {
 307:     entries = new AbstractSet<Map.Entry<K, V>>()
 308:     {
 309:       public int size()
 310:       {
 311:         return cardinality;
 312:       }
 313: 
 314:       public Iterator<Map.Entry<K, V>> iterator()
 315:       {
 316:         return new Iterator<Map.Entry<K, V>>()
 317:         {
 318:           int count = 0;
 319:           int index = -1;
 320: 
 321:           public boolean hasNext()
 322:           {
 323:         return count < cardinality;
 324:           }
 325: 
 326:           public Map.Entry<K,V> next()
 327:           {
 328:         ++count;
 329:         for (++index; store[index] == emptySlot; ++index)
 330:           ;
 331:         // FIXME: we could just return something that
 332:         // only knows the index.  That would be cleaner.
 333:         return new AbstractMap.SimpleEntry<K, V>(enumClass.getEnumConstants()[index],
 334:                                store[index])
 335:         {
 336:           public V setValue(V newVal)
 337:           {
 338:             value = newVal;
 339:             return put(key, newVal);
 340:           }
 341:         };
 342:           }
 343: 
 344:           public void remove()
 345:           {
 346:         --cardinality;
 347:         store[index] = (V) emptySlot;
 348:           }
 349:         };
 350:       }
 351: 
 352:       public void clear()
 353:       {
 354:         EnumMap.this.clear();
 355:       }
 356: 
 357:       public boolean contains(Object o)
 358:       {
 359:         if (! (o instanceof Map.Entry))
 360:           return false;
 361:         Map.Entry<K, V> other = (Map.Entry<K, V>) o;
 362:         return (containsKey(other.getKey())
 363:             && AbstractCollection.equals(get(other.getKey()),
 364:                          other.getValue()));
 365:       }
 366: 
 367:       public boolean remove(Object o)
 368:       {
 369:         if (! (o instanceof Map.Entry))
 370:           return false;
 371:         Map.Entry<K, V> other = (Map.Entry<K, V>) o;
 372:         return EnumMap.this.remove(other.getKey()) != null;
 373:       }
 374:     };
 375:       }
 376:     return entries;
 377:   }
 378: 
 379:   public boolean equals(Object o)
 380:   {
 381:     if (! (o instanceof EnumMap))
 382:       return false;
 383:     EnumMap<K, V> other = (EnumMap<K, V>) o;
 384:     if (other.enumClass != enumClass || other.cardinality != cardinality)
 385:       return false;
 386:     return Arrays.equals(store, other.store);
 387:   }
 388: 
 389:   public EnumMap<K, V> clone()
 390:   {
 391:     EnumMap<K, V> result;
 392:     try
 393:       {
 394:     result = (EnumMap<K, V>) super.clone();
 395:       }
 396:     catch (CloneNotSupportedException ignore)
 397:       {
 398:     // Can't happen.
 399:     result = null;
 400:       }
 401:     result.store = (V[]) store.clone();
 402:     return result;
 403:   }
 404: 
 405: }