J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.util; |
| 27 | |
| 28 | import sun.misc.SharedSecrets; |
| 29 | |
| 30 | /** |
| 31 | * A specialized {@link Set} implementation for use with enum types. All of |
| 32 | * the elements in an enum set must come from a single enum type that is |
| 33 | * specified, explicitly or implicitly, when the set is created. Enum sets |
| 34 | * are represented internally as bit vectors. This representation is |
| 35 | * extremely compact and efficient. The space and time performance of this |
| 36 | * class should be good enough to allow its use as a high-quality, typesafe |
| 37 | * alternative to traditional <tt>int</tt>-based "bit flags." Even bulk |
| 38 | * operations (such as <tt>containsAll</tt> and <tt>retainAll</tt>) should |
| 39 | * run very quickly if their argument is also an enum set. |
| 40 | * |
| 41 | * <p>The iterator returned by the <tt>iterator</tt> method traverses the |
| 42 | * elements in their <i>natural order</i> (the order in which the enum |
| 43 | * constants are declared). The returned iterator is <i>weakly |
| 44 | * consistent</i>: it will never throw {@link ConcurrentModificationException} |
| 45 | * and it may or may not show the effects of any modifications to the set that |
| 46 | * occur while the iteration is in progress. |
| 47 | * |
| 48 | * <p>Null elements are not permitted. Attempts to insert a null element |
| 49 | * will throw {@link NullPointerException}. Attempts to test for the |
| 50 | * presence of a null element or to remove one will, however, function |
| 51 | * properly. |
| 52 | * |
| 53 | * <P>Like most collection implementations, <tt>EnumSet</tt> is not |
| 54 | * synchronized. If multiple threads access an enum set concurrently, and at |
| 55 | * least one of the threads modifies the set, it should be synchronized |
| 56 | * externally. This is typically accomplished by synchronizing on some |
| 57 | * object that naturally encapsulates the enum set. If no such object exists, |
| 58 | * the set should be "wrapped" using the {@link Collections#synchronizedSet} |
| 59 | * method. This is best done at creation time, to prevent accidental |
| 60 | * unsynchronized access: |
| 61 | * |
| 62 | * <pre> |
| 63 | * Set<MyEnum> s = Collections.synchronizedSet(EnumSet.noneOf(MyEnum.class)); |
| 64 | * </pre> |
| 65 | * |
| 66 | * <p>Implementation note: All basic operations execute in constant time. |
| 67 | * They are likely (though not guaranteed) to be much faster than their |
| 68 | * {@link HashSet} counterparts. Even bulk operations execute in |
| 69 | * constant time if their argument is also an enum set. |
| 70 | * |
| 71 | * <p>This class is a member of the |
| 72 | * <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
| 73 | * Java Collections Framework</a>. |
| 74 | * |
| 75 | * @author Josh Bloch |
| 76 | * @since 1.5 |
| 77 | * @see EnumMap |
| 78 | * @serial exclude |
| 79 | */ |
| 80 | public abstract class EnumSet<E extends Enum<E>> extends AbstractSet<E> |
| 81 | implements Cloneable, java.io.Serializable |
| 82 | { |
| 83 | /** |
| 84 | * The class of all the elements of this set. |
| 85 | */ |
| 86 | final Class<E> elementType; |
| 87 | |
| 88 | /** |
| 89 | * All of the values comprising T. (Cached for performance.) |
| 90 | */ |
| 91 | final Enum[] universe; |
| 92 | |
| 93 | private static Enum[] ZERO_LENGTH_ENUM_ARRAY = new Enum[0]; |
| 94 | |
| 95 | EnumSet(Class<E>elementType, Enum[] universe) { |
| 96 | this.elementType = elementType; |
| 97 | this.universe = universe; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Creates an empty enum set with the specified element type. |
| 102 | * |
| 103 | * @param elementType the class object of the element type for this enum |
| 104 | * set |
| 105 | * @throws NullPointerException if <tt>elementType</tt> is null |
| 106 | */ |
| 107 | public static <E extends Enum<E>> EnumSet<E> noneOf(Class<E> elementType) { |
| 108 | Enum[] universe = getUniverse(elementType); |
| 109 | if (universe == null) |
| 110 | throw new ClassCastException(elementType + " not an enum"); |
| 111 | |
| 112 | if (universe.length <= 64) |
| 113 | return new RegularEnumSet<E>(elementType, universe); |
| 114 | else |
| 115 | return new JumboEnumSet<E>(elementType, universe); |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Creates an enum set containing all of the elements in the specified |
| 120 | * element type. |
| 121 | * |
| 122 | * @param elementType the class object of the element type for this enum |
| 123 | * set |
| 124 | * @throws NullPointerException if <tt>elementType</tt> is null |
| 125 | */ |
| 126 | public static <E extends Enum<E>> EnumSet<E> allOf(Class<E> elementType) { |
| 127 | EnumSet<E> result = noneOf(elementType); |
| 128 | result.addAll(); |
| 129 | return result; |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * Adds all of the elements from the appropriate enum type to this enum |
| 134 | * set, which is empty prior to the call. |
| 135 | */ |
| 136 | abstract void addAll(); |
| 137 | |
| 138 | /** |
| 139 | * Creates an enum set with the same element type as the specified enum |
| 140 | * set, initially containing the same elements (if any). |
| 141 | * |
| 142 | * @param s the enum set from which to initialize this enum set |
| 143 | * @throws NullPointerException if <tt>s</tt> is null |
| 144 | */ |
| 145 | public static <E extends Enum<E>> EnumSet<E> copyOf(EnumSet<E> s) { |
| 146 | return s.clone(); |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * Creates an enum set initialized from the specified collection. If |
| 151 | * the specified collection is an <tt>EnumSet</tt> instance, this static |
| 152 | * factory method behaves identically to {@link #copyOf(EnumSet)}. |
| 153 | * Otherwise, the specified collection must contain at least one element |
| 154 | * (in order to determine the new enum set's element type). |
| 155 | * |
| 156 | * @param c the collection from which to initialize this enum set |
| 157 | * @throws IllegalArgumentException if <tt>c</tt> is not an |
| 158 | * <tt>EnumSet</tt> instance and contains no elements |
| 159 | * @throws NullPointerException if <tt>c</tt> is null |
| 160 | */ |
| 161 | public static <E extends Enum<E>> EnumSet<E> copyOf(Collection<E> c) { |
| 162 | if (c instanceof EnumSet) { |
| 163 | return ((EnumSet<E>)c).clone(); |
| 164 | } else { |
| 165 | if (c.isEmpty()) |
| 166 | throw new IllegalArgumentException("Collection is empty"); |
| 167 | Iterator<E> i = c.iterator(); |
| 168 | E first = i.next(); |
| 169 | EnumSet<E> result = EnumSet.of(first); |
| 170 | while (i.hasNext()) |
| 171 | result.add(i.next()); |
| 172 | return result; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * Creates an enum set with the same element type as the specified enum |
| 178 | * set, initially containing all the elements of this type that are |
| 179 | * <i>not</i> contained in the specified set. |
| 180 | * |
| 181 | * @param s the enum set from whose complement to initialize this enum set |
| 182 | * @throws NullPointerException if <tt>s</tt> is null |
| 183 | */ |
| 184 | public static <E extends Enum<E>> EnumSet<E> complementOf(EnumSet<E> s) { |
| 185 | EnumSet<E> result = copyOf(s); |
| 186 | result.complement(); |
| 187 | return result; |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * Creates an enum set initially containing the specified element. |
| 192 | * |
| 193 | * Overloadings of this method exist to initialize an enum set with |
| 194 | * one through five elements. A sixth overloading is provided that |
| 195 | * uses the varargs feature. This overloading may be used to create |
| 196 | * an enum set initially containing an arbitrary number of elements, but |
| 197 | * is likely to run slower than the overloadings that do not use varargs. |
| 198 | * |
| 199 | * @param e the element that this set is to contain initially |
| 200 | * @throws NullPointerException if <tt>e</tt> is null |
| 201 | * @return an enum set initially containing the specified element |
| 202 | */ |
| 203 | public static <E extends Enum<E>> EnumSet<E> of(E e) { |
| 204 | EnumSet<E> result = noneOf(e.getDeclaringClass()); |
| 205 | result.add(e); |
| 206 | return result; |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Creates an enum set initially containing the specified elements. |
| 211 | * |
| 212 | * Overloadings of this method exist to initialize an enum set with |
| 213 | * one through five elements. A sixth overloading is provided that |
| 214 | * uses the varargs feature. This overloading may be used to create |
| 215 | * an enum set initially containing an arbitrary number of elements, but |
| 216 | * is likely to run slower than the overloadings that do not use varargs. |
| 217 | * |
| 218 | * @param e1 an element that this set is to contain initially |
| 219 | * @param e2 another element that this set is to contain initially |
| 220 | * @throws NullPointerException if any parameters are null |
| 221 | * @return an enum set initially containing the specified elements |
| 222 | */ |
| 223 | public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2) { |
| 224 | EnumSet<E> result = noneOf(e1.getDeclaringClass()); |
| 225 | result.add(e1); |
| 226 | result.add(e2); |
| 227 | return result; |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Creates an enum set initially containing the specified elements. |
| 232 | * |
| 233 | * Overloadings of this method exist to initialize an enum set with |
| 234 | * one through five elements. A sixth overloading is provided that |
| 235 | * uses the varargs feature. This overloading may be used to create |
| 236 | * an enum set initially containing an arbitrary number of elements, but |
| 237 | * is likely to run slower than the overloadings that do not use varargs. |
| 238 | * |
| 239 | * @param e1 an element that this set is to contain initially |
| 240 | * @param e2 another element that this set is to contain initially |
| 241 | * @param e3 another element that this set is to contain initially |
| 242 | * @throws NullPointerException if any parameters are null |
| 243 | * @return an enum set initially containing the specified elements |
| 244 | */ |
| 245 | public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3) { |
| 246 | EnumSet<E> result = noneOf(e1.getDeclaringClass()); |
| 247 | result.add(e1); |
| 248 | result.add(e2); |
| 249 | result.add(e3); |
| 250 | return result; |
| 251 | } |
| 252 | |
| 253 | /** |
| 254 | * Creates an enum set initially containing the specified elements. |
| 255 | * |
| 256 | * Overloadings of this method exist to initialize an enum set with |
| 257 | * one through five elements. A sixth overloading is provided that |
| 258 | * uses the varargs feature. This overloading may be used to create |
| 259 | * an enum set initially containing an arbitrary number of elements, but |
| 260 | * is likely to run slower than the overloadings that do not use varargs. |
| 261 | * |
| 262 | * @param e1 an element that this set is to contain initially |
| 263 | * @param e2 another element that this set is to contain initially |
| 264 | * @param e3 another element that this set is to contain initially |
| 265 | * @param e4 another element that this set is to contain initially |
| 266 | * @throws NullPointerException if any parameters are null |
| 267 | * @return an enum set initially containing the specified elements |
| 268 | */ |
| 269 | public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4) { |
| 270 | EnumSet<E> result = noneOf(e1.getDeclaringClass()); |
| 271 | result.add(e1); |
| 272 | result.add(e2); |
| 273 | result.add(e3); |
| 274 | result.add(e4); |
| 275 | return result; |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * Creates an enum set initially containing the specified elements. |
| 280 | * |
| 281 | * Overloadings of this method exist to initialize an enum set with |
| 282 | * one through five elements. A sixth overloading is provided that |
| 283 | * uses the varargs feature. This overloading may be used to create |
| 284 | * an enum set initially containing an arbitrary number of elements, but |
| 285 | * is likely to run slower than the overloadings that do not use varargs. |
| 286 | * |
| 287 | * @param e1 an element that this set is to contain initially |
| 288 | * @param e2 another element that this set is to contain initially |
| 289 | * @param e3 another element that this set is to contain initially |
| 290 | * @param e4 another element that this set is to contain initially |
| 291 | * @param e5 another element that this set is to contain initially |
| 292 | * @throws NullPointerException if any parameters are null |
| 293 | * @return an enum set initially containing the specified elements |
| 294 | */ |
| 295 | public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4, |
| 296 | E e5) |
| 297 | { |
| 298 | EnumSet<E> result = noneOf(e1.getDeclaringClass()); |
| 299 | result.add(e1); |
| 300 | result.add(e2); |
| 301 | result.add(e3); |
| 302 | result.add(e4); |
| 303 | result.add(e5); |
| 304 | return result; |
| 305 | } |
| 306 | |
| 307 | /** |
| 308 | * Creates an enum set initially containing the specified elements. |
| 309 | * This factory, whose parameter list uses the varargs feature, may |
| 310 | * be used to create an enum set initially containing an arbitrary |
| 311 | * number of elements, but it is likely to run slower than the overloadings |
| 312 | * that do not use varargs. |
| 313 | * |
| 314 | * @param first an element that the set is to contain initially |
| 315 | * @param rest the remaining elements the set is to contain initially |
| 316 | * @throws NullPointerException if any of the specified elements are null, |
| 317 | * or if <tt>rest</tt> is null |
| 318 | * @return an enum set initially containing the specified elements |
| 319 | */ |
| 320 | public static <E extends Enum<E>> EnumSet<E> of(E first, E... rest) { |
| 321 | EnumSet<E> result = noneOf(first.getDeclaringClass()); |
| 322 | result.add(first); |
| 323 | for (E e : rest) |
| 324 | result.add(e); |
| 325 | return result; |
| 326 | } |
| 327 | |
| 328 | /** |
| 329 | * Creates an enum set initially containing all of the elements in the |
| 330 | * range defined by the two specified endpoints. The returned set will |
| 331 | * contain the endpoints themselves, which may be identical but must not |
| 332 | * be out of order. |
| 333 | * |
| 334 | * @param from the first element in the range |
| 335 | * @param to the last element in the range |
| 336 | * @throws NullPointerException if {@code from} or {@code to} are null |
| 337 | * @throws IllegalArgumentException if {@code from.compareTo(to) > 0} |
| 338 | * @return an enum set initially containing all of the elements in the |
| 339 | * range defined by the two specified endpoints |
| 340 | */ |
| 341 | public static <E extends Enum<E>> EnumSet<E> range(E from, E to) { |
| 342 | if (from.compareTo(to) > 0) |
| 343 | throw new IllegalArgumentException(from + " > " + to); |
| 344 | EnumSet<E> result = noneOf(from.getDeclaringClass()); |
| 345 | result.addRange(from, to); |
| 346 | return result; |
| 347 | } |
| 348 | |
| 349 | /** |
| 350 | * Adds the specified range to this enum set, which is empty prior |
| 351 | * to the call. |
| 352 | */ |
| 353 | abstract void addRange(E from, E to); |
| 354 | |
| 355 | /** |
| 356 | * Returns a copy of this set. |
| 357 | * |
| 358 | * @return a copy of this set |
| 359 | */ |
| 360 | public EnumSet<E> clone() { |
| 361 | try { |
| 362 | return (EnumSet<E>) super.clone(); |
| 363 | } catch(CloneNotSupportedException e) { |
| 364 | throw new AssertionError(e); |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | /** |
| 369 | * Complements the contents of this enum set. |
| 370 | */ |
| 371 | abstract void complement(); |
| 372 | |
| 373 | /** |
| 374 | * Throws an exception if e is not of the correct type for this enum set. |
| 375 | */ |
| 376 | final void typeCheck(E e) { |
| 377 | Class eClass = e.getClass(); |
| 378 | if (eClass != elementType && eClass.getSuperclass() != elementType) |
| 379 | throw new ClassCastException(eClass + " != " + elementType); |
| 380 | } |
| 381 | |
| 382 | /** |
| 383 | * Returns all of the values comprising E. |
| 384 | * The result is uncloned, cached, and shared by all callers. |
| 385 | */ |
| 386 | private static <E extends Enum<E>> E[] getUniverse(Class<E> elementType) { |
| 387 | return SharedSecrets.getJavaLangAccess() |
| 388 | .getEnumConstantsShared(elementType); |
| 389 | } |
| 390 | |
| 391 | /** |
| 392 | * This class is used to serialize all EnumSet instances, regardless of |
| 393 | * implementation type. It captures their "logical contents" and they |
| 394 | * are reconstructed using public static factories. This is necessary |
| 395 | * to ensure that the existence of a particular implementation type is |
| 396 | * an implementation detail. |
| 397 | * |
| 398 | * @serial include |
| 399 | */ |
| 400 | private static class SerializationProxy <E extends Enum<E>> |
| 401 | implements java.io.Serializable |
| 402 | { |
| 403 | /** |
| 404 | * The element type of this enum set. |
| 405 | * |
| 406 | * @serial |
| 407 | */ |
| 408 | private final Class<E> elementType; |
| 409 | |
| 410 | /** |
| 411 | * The elements contained in this enum set. |
| 412 | * |
| 413 | * @serial |
| 414 | */ |
| 415 | private final Enum[] elements; |
| 416 | |
| 417 | SerializationProxy(EnumSet<E> set) { |
| 418 | elementType = set.elementType; |
| 419 | elements = set.toArray(ZERO_LENGTH_ENUM_ARRAY); |
| 420 | } |
| 421 | |
| 422 | private Object readResolve() { |
| 423 | EnumSet<E> result = EnumSet.noneOf(elementType); |
| 424 | for (Enum e : elements) |
| 425 | result.add((E)e); |
| 426 | return result; |
| 427 | } |
| 428 | |
| 429 | private static final long serialVersionUID = 362491234563181265L; |
| 430 | } |
| 431 | |
| 432 | Object writeReplace() { |
| 433 | return new SerializationProxy<E>(this); |
| 434 | } |
| 435 | } |