1 /*
2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 /**
29 * Private implementation class for EnumSet, for "jumbo" enum types
30 * (i.e., those with more than 64 elements).
31 *
32 * @author Josh Bloch
33 * @since 1.5
34 * @serial exclude
35 */
36 class JumboEnumSet<E extends Enum<E>> extends EnumSet<E> {
37 @java.io.Serial
38 private static final long serialVersionUID = 334349849919042784L;
39
40 /**
41 * Bit vector representation of this set. The ith bit of the jth
42 * element of this array represents the presence of universe[64*j +i]
43 * in this set.
44 */
45 private long elements[];
46
47 // Redundant - maintained for performance
48 private int size = 0;
49
50 JumboEnumSet(Class<E>elementType, Enum<?>[] universe) {
51 super(elementType, universe);
52 elements = new long[(universe.length + 63) >>> 6];
53 }
54
55 void addRange(E from, E to) {
56 int fromIndex = from.ordinal() >>> 6;
57 int toIndex = to.ordinal() >>> 6;
58
59 if (fromIndex == toIndex) {
60 elements[fromIndex] = (-1L >>> (from.ordinal() - to.ordinal() - 1))
61 << from.ordinal();
62 } else {
63 elements[fromIndex] = (-1L << from.ordinal());
64 for (int i = fromIndex + 1; i < toIndex; i++)
65 elements[i] = -1;
66 elements[toIndex] = -1L >>> (63 - to.ordinal());
67 }
68 size = to.ordinal() - from.ordinal() + 1;
69 }
70
71 void addAll() {
72 for (int i = 0; i < elements.length; i++)
73 elements[i] = -1;
74 elements[elements.length - 1] >>>= -universe.length;
75 size = universe.length;
76 }
77
78 void complement() {
79 for (int i = 0; i < elements.length; i++)
80 elements[i] = ~elements[i];
81 elements[elements.length - 1] &= (-1L >>> -universe.length);
82 size = universe.length - size;
83 }
84
85 /**
86 * Returns an iterator over the elements contained in this set. The
87 * iterator traverses the elements in their <i>natural order</i> (which is
88 * the order in which the enum constants are declared). The returned
89 * Iterator is a "weakly consistent" iterator that will never throw {@link
90 * ConcurrentModificationException}.
91 *
92 * @return an iterator over the elements contained in this set
93 */
94 public Iterator<E> iterator() {
95 return new EnumSetIterator<>();
96 }
97
98 private class EnumSetIterator<E extends Enum<E>> implements Iterator<E> {
99 /**
100 * A bit vector representing the elements in the current "word"
101 * of the set not yet returned by this iterator.
102 */
103 long unseen;
104
105 /**
106 * The index corresponding to unseen in the elements array.
107 */
108 int unseenIndex = 0;
109
110 /**
111 * The bit representing the last element returned by this iterator
112 * but not removed, or zero if no such element exists.
113 */
114 long lastReturned = 0;
115
116 /**
117 * The index corresponding to lastReturned in the elements array.
118 */
119 int lastReturnedIndex = 0;
120
121 EnumSetIterator() {
122 unseen = elements[0];
123 }
124
125 @Override
126 public boolean hasNext() {
127 while (unseen == 0 && unseenIndex < elements.length - 1)
128 unseen = elements[++unseenIndex];
129 return unseen != 0;
130 }
131
132 @Override
133 @SuppressWarnings("unchecked")
134 public E next() {
135 if (!hasNext())
136 throw new NoSuchElementException();
137 lastReturned = unseen & -unseen;
138 lastReturnedIndex = unseenIndex;
139 unseen -= lastReturned;
140 return (E) universe[(lastReturnedIndex << 6)
141 + Long.numberOfTrailingZeros(lastReturned)];
142 }
143
144 @Override
145 public void remove() {
146 if (lastReturned == 0)
147 throw new IllegalStateException();
148 final long oldElements = elements[lastReturnedIndex];
149 elements[lastReturnedIndex] &= ~lastReturned;
150 if (oldElements != elements[lastReturnedIndex]) {
151 size--;
152 }
153 lastReturned = 0;
154 }
155 }
156
157 /**
158 * Returns the number of elements in this set.
159 *
160 * @return the number of elements in this set
161 */
162 public int size() {
163 return size;
164 }
165
166 /**
167 * Returns {@code true} if this set contains no elements.
168 *
169 * @return {@code true} if this set contains no elements
170 */
171 public boolean isEmpty() {
172 return size == 0;
173 }
174
175 /**
176 * Returns {@code true} if this set contains the specified element.
177 *
178 * @param e element to be checked for containment in this collection
179 * @return {@code true} if this set contains the specified element
180 */
181 public boolean contains(Object e) {
182 if (e == null)
183 return false;
184 Class<?> eClass = e.getClass();
185 if (eClass != elementType && eClass.getSuperclass() != elementType)
186 return false;
187
188 int eOrdinal = ((Enum<?>)e).ordinal();
189 return (elements[eOrdinal >>> 6] & (1L << eOrdinal)) != 0;
190 }
191
192 // Modification Operations
193
194 /**
195 * Adds the specified element to this set if it is not already present.
196 *
197 * @param e element to be added to this set
198 * @return {@code true} if the set changed as a result of the call
199 *
200 * @throws NullPointerException if {@code e} is null
201 */
202 public boolean add(E e) {
203 typeCheck(e);
204
205 int eOrdinal = e.ordinal();
206 int eWordNum = eOrdinal >>> 6;
207
208 long oldElements = elements[eWordNum];
209 elements[eWordNum] |= (1L << eOrdinal);
210 boolean result = (elements[eWordNum] != oldElements);
211 if (result)
212 size++;
213 return result;
214 }
215
216 /**
217 * Removes the specified element from this set if it is present.
218 *
219 * @param e element to be removed from this set, if present
220 * @return {@code true} if the set contained the specified element
221 */
222 public boolean remove(Object e) {
223 if (e == null)
224 return false;
225 Class<?> eClass = e.getClass();
226 if (eClass != elementType && eClass.getSuperclass() != elementType)
227 return false;
228 int eOrdinal = ((Enum<?>)e).ordinal();
229 int eWordNum = eOrdinal >>> 6;
230
231 long oldElements = elements[eWordNum];
232 elements[eWordNum] &= ~(1L << eOrdinal);
233 boolean result = (elements[eWordNum] != oldElements);
234 if (result)
235 size--;
236 return result;
237 }
238
239 // Bulk Operations
240
241 /**
242 * Returns {@code true} if this set contains all of the elements
243 * in the specified collection.
244 *
245 * @param c collection to be checked for containment in this set
246 * @return {@code true} if this set contains all of the elements
247 * in the specified collection
248 * @throws NullPointerException if the specified collection is null
249 */
250 public boolean containsAll(Collection<?> c) {
251 if (!(c instanceof JumboEnumSet))
252 return super.containsAll(c);
253
254 JumboEnumSet<?> es = (JumboEnumSet<?>)c;
255 if (es.elementType != elementType)
256 return es.isEmpty();
257
258 for (int i = 0; i < elements.length; i++)
259 if ((es.elements[i] & ~elements[i]) != 0)
260 return false;
261 return true;
262 }
263
264 /**
265 * Adds all of the elements in the specified collection to this set.
266 *
267 * @param c collection whose elements are to be added to this set
268 * @return {@code true} if this set changed as a result of the call
269 * @throws NullPointerException if the specified collection or any of
270 * its elements are null
271 */
272 public boolean addAll(Collection<? extends E> c) {
273 if (!(c instanceof JumboEnumSet))
274 return super.addAll(c);
275
276 JumboEnumSet<?> es = (JumboEnumSet<?>)c;
277 if (es.elementType != elementType) {
278 if (es.isEmpty())
279 return false;
280 else
281 throw new ClassCastException(
282 es.elementType + " != " + elementType);
283 }
284
285 for (int i = 0; i < elements.length; i++)
286 elements[i] |= es.elements[i];
287 return recalculateSize();
288 }
289
290 /**
291 * Removes from this set all of its elements that are contained in
292 * the specified collection.
293 *
294 * @param c elements to be removed from this set
295 * @return {@code true} if this set changed as a result of the call
296 * @throws NullPointerException if the specified collection is null
297 */
298 public boolean removeAll(Collection<?> c) {
299 if (!(c instanceof JumboEnumSet))
300 return super.removeAll(c);
301
302 JumboEnumSet<?> es = (JumboEnumSet<?>)c;
303 if (es.elementType != elementType)
304 return false;
305
306 for (int i = 0; i < elements.length; i++)
307 elements[i] &= ~es.elements[i];
308 return recalculateSize();
309 }
310
311 /**
312 * Retains only the elements in this set that are contained in the
313 * specified collection.
314 *
315 * @param c elements to be retained in this set
316 * @return {@code true} if this set changed as a result of the call
317 * @throws NullPointerException if the specified collection is null
318 */
319 public boolean retainAll(Collection<?> c) {
320 if (!(c instanceof JumboEnumSet))
321 return super.retainAll(c);
322
323 JumboEnumSet<?> es = (JumboEnumSet<?>)c;
324 if (es.elementType != elementType) {
325 boolean changed = (size != 0);
326 clear();
327 return changed;
328 }
329
330 for (int i = 0; i < elements.length; i++)
331 elements[i] &= es.elements[i];
332 return recalculateSize();
333 }
334
335 /**
336 * Removes all of the elements from this set.
337 */
338 public void clear() {
339 Arrays.fill(elements, 0);
340 size = 0;
341 }
342
343 /**
344 * Compares the specified object with this set for equality. Returns
345 * {@code true} if the given object is also a set, the two sets have
346 * the same size, and every member of the given set is contained in
347 * this set.
348 *
349 * @param o object to be compared for equality with this set
350 * @return {@code true} if the specified object is equal to this set
351 */
352 public boolean equals(Object o) {
353 if (!(o instanceof JumboEnumSet))
354 return super.equals(o);
355
356 JumboEnumSet<?> es = (JumboEnumSet<?>)o;
357 if (es.elementType != elementType)
358 return size == 0 && es.size == 0;
359
360 return Arrays.equals(es.elements, elements);
361 }
362
363 /**
364 * Recalculates the size of the set. Returns true if it's changed.
365 */
366 private boolean recalculateSize() {
367 int oldSize = size;
368 size = 0;
369 for (long elt : elements)
370 size += Long.bitCount(elt);
371
372 return size != oldSize;
373 }
374
375 public EnumSet<E> clone() {
376 JumboEnumSet<E> result = (JumboEnumSet<E>) super.clone();
377 result.elements = result.elements.clone();
378 return result;
379 }
380 }