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 "regular sized" enum types
30 * (i.e., those with 64 or fewer enum constants).
31 *
32 * @author Josh Bloch
33 * @since 1.5
34 * @serial exclude
35 */
36 class RegularEnumSet<E extends Enum<E>> extends EnumSet<E> {
37 private static final long serialVersionUID = 3411599620347842686L;
38 /**
39 * Bit vector representation of this set. The 2^k bit indicates the
40 * presence of universe[k] in this set.
41 */
42 private long elements = 0L;
43
44 RegularEnumSet(Class<E>elementType, Enum<?>[] universe) {
45 super(elementType, universe);
46 }
47
48 void addRange(E from, E to) {
49 elements = (-1L >>> (from.ordinal() - to.ordinal() - 1)) << from.ordinal();
50 }
51
52 void addAll() {
53 if (universe.length != 0)
54 elements = -1L >>> -universe.length;
55 }
56
57 void complement() {
58 if (universe.length != 0) {
59 elements = ~elements;
60 elements &= -1L >>> -universe.length; // Mask unused bits
61 }
62 }
63
64 /**
65 * Returns an iterator over the elements contained in this set. The
66 * iterator traverses the elements in their <i>natural order</i> (which is
67 * the order in which the enum constants are declared). The returned
68 * Iterator is a "snapshot" iterator that will never throw {@link
69 * ConcurrentModificationException}; the elements are traversed as they
70 * existed when this call was invoked.
71 *
72 * @return an iterator over the elements contained in this set
73 */
74 public Iterator<E> iterator() {
75 return new EnumSetIterator<>();
76 }
77
78 private class EnumSetIterator<E extends Enum<E>> implements Iterator<E> {
79 /**
80 * A bit vector representing the elements in the set not yet
81 * returned by this iterator.
82 */
83 long unseen;
84
85 /**
86 * The bit representing the last element returned by this iterator
87 * but not removed, or zero if no such element exists.
88 */
89 long lastReturned = 0;
90
91 EnumSetIterator() {
92 unseen = elements;
93 }
94
95 public boolean hasNext() {
96 return unseen != 0;
97 }
98
99 @SuppressWarnings("unchecked")
100 public E next() {
101 if (unseen == 0)
102 throw new NoSuchElementException();
103 lastReturned = unseen & -unseen;
104 unseen -= lastReturned;
105 return (E) universe[Long.numberOfTrailingZeros(lastReturned)];
106 }
107
108 public void remove() {
109 if (lastReturned == 0)
110 throw new IllegalStateException();
111 elements &= ~lastReturned;
112 lastReturned = 0;
113 }
114 }
115
116 /**
117 * Returns the number of elements in this set.
118 *
119 * @return the number of elements in this set
120 */
121 public int size() {
122 return Long.bitCount(elements);
123 }
124
125 /**
126 * Returns {@code true} if this set contains no elements.
127 *
128 * @return {@code true} if this set contains no elements
129 */
130 public boolean isEmpty() {
131 return elements == 0;
132 }
133
134 /**
135 * Returns {@code true} if this set contains the specified element.
136 *
137 * @param e element to be checked for containment in this collection
138 * @return {@code true} if this set contains the specified element
139 */
140 public boolean contains(Object e) {
141 if (e == null)
142 return false;
143 Class<?> eClass = e.getClass();
144 if (eClass != elementType && eClass.getSuperclass() != elementType)
145 return false;
146
147 return (elements & (1L << ((Enum<?>)e).ordinal())) != 0;
148 }
149
150 // Modification Operations
151
152 /**
153 * Adds the specified element to this set if it is not already present.
154 *
155 * @param e element to be added to this set
156 * @return {@code true} if the set changed as a result of the call
157 *
158 * @throws NullPointerException if {@code e} is null
159 */
160 public boolean add(E e) {
161 typeCheck(e);
162
163 long oldElements = elements;
164 elements |= (1L << ((Enum<?>)e).ordinal());
165 return elements != oldElements;
166 }
167
168 /**
169 * Removes the specified element from this set if it is present.
170 *
171 * @param e element to be removed from this set, if present
172 * @return {@code true} if the set contained the specified element
173 */
174 public boolean remove(Object e) {
175 if (e == null)
176 return false;
177 Class<?> eClass = e.getClass();
178 if (eClass != elementType && eClass.getSuperclass() != elementType)
179 return false;
180
181 long oldElements = elements;
182 elements &= ~(1L << ((Enum<?>)e).ordinal());
183 return elements != oldElements;
184 }
185
186 // Bulk Operations
187
188 /**
189 * Returns {@code true} if this set contains all of the elements
190 * in the specified collection.
191 *
192 * @param c collection to be checked for containment in this set
193 * @return {@code true} if this set contains all of the elements
194 * in the specified collection
195 * @throws NullPointerException if the specified collection is null
196 */
197 public boolean containsAll(Collection<?> c) {
198 if (!(c instanceof RegularEnumSet))
199 return super.containsAll(c);
200
201 RegularEnumSet<?> es = (RegularEnumSet<?>)c;
202 if (es.elementType != elementType)
203 return es.isEmpty();
204
205 return (es.elements & ~elements) == 0;
206 }
207
208 /**
209 * Adds all of the elements in the specified collection to this set.
210 *
211 * @param c collection whose elements are to be added to this set
212 * @return {@code true} if this set changed as a result of the call
213 * @throws NullPointerException if the specified collection or any
214 * of its elements are null
215 */
216 public boolean addAll(Collection<? extends E> c) {
217 if (!(c instanceof RegularEnumSet))
218 return super.addAll(c);
219
220 RegularEnumSet<?> es = (RegularEnumSet<?>)c;
221 if (es.elementType != elementType) {
222 if (es.isEmpty())
223 return false;
224 else
225 throw new ClassCastException(
226 es.elementType + " != " + elementType);
227 }
228
229 long oldElements = elements;
230 elements |= es.elements;
231 return elements != oldElements;
232 }
233
234 /**
235 * Removes from this set all of its elements that are contained in
236 * the specified collection.
237 *
238 * @param c elements to be removed from this set
239 * @return {@code true} if this set changed as a result of the call
240 * @throws NullPointerException if the specified collection is null
241 */
242 public boolean removeAll(Collection<?> c) {
243 if (!(c instanceof RegularEnumSet))
244 return super.removeAll(c);
245
246 RegularEnumSet<?> es = (RegularEnumSet<?>)c;
247 if (es.elementType != elementType)
248 return false;
249
250 long oldElements = elements;
251 elements &= ~es.elements;
252 return elements != oldElements;
253 }
254
255 /**
256 * Retains only the elements in this set that are contained in the
257 * specified collection.
258 *
259 * @param c elements to be retained in this set
260 * @return {@code true} if this set changed as a result of the call
261 * @throws NullPointerException if the specified collection is null
262 */
263 public boolean retainAll(Collection<?> c) {
264 if (!(c instanceof RegularEnumSet))
265 return super.retainAll(c);
266
267 RegularEnumSet<?> es = (RegularEnumSet<?>)c;
268 if (es.elementType != elementType) {
269 boolean changed = (elements != 0);
270 elements = 0;
271 return changed;
272 }
273
274 long oldElements = elements;
275 elements &= es.elements;
276 return elements != oldElements;
277 }
278
279 /**
280 * Removes all of the elements from this set.
281 */
282 public void clear() {
283 elements = 0;
284 }
285
286 /**
287 * Compares the specified object with this set for equality. Returns
288 * {@code true} if the given object is also a set, the two sets have
289 * the same size, and every member of the given set is contained in
290 * this set.
291 *
292 * @param o object to be compared for equality with this set
293 * @return {@code true} if the specified object is equal to this set
294 */
295 public boolean equals(Object o) {
296 if (!(o instanceof RegularEnumSet))
297 return super.equals(o);
298
299 RegularEnumSet<?> es = (RegularEnumSet<?>)o;
300 if (es.elementType != elementType)
301 return elements == 0 && es.elements == 0;
302 return es.elements == elements;
303 }
304 }
305