1 /*
2 * Copyright (c) 2003, 2006, 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 public E next() {
100 if (unseen == 0)
101 throw new NoSuchElementException();
102 lastReturned = unseen & -unseen;
103 unseen -= lastReturned;
104 return (E) universe[Long.numberOfTrailingZeros(lastReturned)];
105 }
106
107 public void remove() {
108 if (lastReturned == 0)
109 throw new IllegalStateException();
110 elements &= ~lastReturned;
111 lastReturned = 0;
112 }
113 }
114
115 /**
116 * Returns the number of elements in this set.
117 *
118 * @return the number of elements in this set
119 */
120 public int size() {
121 return Long.bitCount(elements);
122 }
123
124 /**
125 * Returns <tt>true</tt> if this set contains no elements.
126 *
127 * @return <tt>true</tt> if this set contains no elements
128 */
129 public boolean isEmpty() {
130 return elements == 0;
131 }
132
133 /**
134 * Returns <tt>true</tt> if this set contains the specified element.
135 *
136 * @param e element to be checked for containment in this collection
137 * @return <tt>true</tt> if this set contains the specified element
138 */
139 public boolean contains(Object e) {
140 if (e == null)
141 return false;
142 Class eClass = e.getClass();
143 if (eClass != elementType && eClass.getSuperclass() != elementType)
144 return false;
145
146 return (elements & (1L << ((Enum)e).ordinal())) != 0;
147 }
148
149 // Modification Operations
150
151 /**
152 * Adds the specified element to this set if it is not already present.
153 *
154 * @param e element to be added to this set
155 * @return <tt>true</tt> if the set changed as a result of the call
156 *
157 * @throws NullPointerException if <tt>e</tt> is null
158 */
159 public boolean add(E e) {
160 typeCheck(e);
161
162 long oldElements = elements;
163 elements |= (1L << ((Enum)e).ordinal());
164 return elements != oldElements;
165 }
166
167 /**
168 * Removes the specified element from this set if it is present.
169 *
170 * @param e element to be removed from this set, if present
171 * @return <tt>true</tt> if the set contained the specified element
172 */
173 public boolean remove(Object e) {
174 if (e == null)
175 return false;
176 Class eClass = e.getClass();
177 if (eClass != elementType && eClass.getSuperclass() != elementType)
178 return false;
179
180 long oldElements = elements;
181 elements &= ~(1L << ((Enum)e).ordinal());
182 return elements != oldElements;
183 }
184
185 // Bulk Operations
186
187 /**
188 * Returns <tt>true</tt> if this set contains all of the elements
189 * in the specified collection.
190 *
191 * @param c collection to be checked for containment in this set
192 * @return <tt>true</tt> if this set contains all of the elements
193 * in the specified collection
194 * @throws NullPointerException if the specified collection is null
195 */
196 public boolean containsAll(Collection<?> c) {
197 if (!(c instanceof RegularEnumSet))
198 return super.containsAll(c);
199
200 RegularEnumSet es = (RegularEnumSet)c;
201 if (es.elementType != elementType)
202 return es.isEmpty();
203
204 return (es.elements & ~elements) == 0;
205 }
206
207 /**
208 * Adds all of the elements in the specified collection to this set.
209 *
210 * @param c collection whose elements are to be added to this set
211 * @return <tt>true</tt> if this set changed as a result of the call
212 * @throws NullPointerException if the specified collection or any
213 * of its elements are null
214 */
215 public boolean addAll(Collection<? extends E> c) {
216 if (!(c instanceof RegularEnumSet))
217 return super.addAll(c);
218
219 RegularEnumSet es = (RegularEnumSet)c;
220 if (es.elementType != elementType) {
221 if (es.isEmpty())
222 return false;
223 else
224 throw new ClassCastException(
225 es.elementType + " != " + elementType);
226 }
227
228 long oldElements = elements;
229 elements |= es.elements;
230 return elements != oldElements;
231 }
232
233 /**
234 * Removes from this set all of its elements that are contained in
235 * the specified collection.
236 *
237 * @param c elements to be removed from this set
238 * @return <tt>true</tt> if this set changed as a result of the call
239 * @throws NullPointerException if the specified collection is null
240 */
241 public boolean removeAll(Collection<?> c) {
242 if (!(c instanceof RegularEnumSet))
243 return super.removeAll(c);
244
245 RegularEnumSet es = (RegularEnumSet)c;
246 if (es.elementType != elementType)
247 return false;
248
249 long oldElements = elements;
250 elements &= ~es.elements;
251 return elements != oldElements;
252 }
253
254 /**
255 * Retains only the elements in this set that are contained in the
256 * specified collection.
257 *
258 * @param c elements to be retained in this set
259 * @return <tt>true</tt> if this set changed as a result of the call
260 * @throws NullPointerException if the specified collection is null
261 */
262 public boolean retainAll(Collection<?> c) {
263 if (!(c instanceof RegularEnumSet))
264 return super.retainAll(c);
265
266 RegularEnumSet<?> es = (RegularEnumSet<?>)c;
267 if (es.elementType != elementType) {
268 boolean changed = (elements != 0);
269 elements = 0;
270 return changed;
271 }
272
273 long oldElements = elements;
274 elements &= es.elements;
275 return elements != oldElements;
276 }
277
278 /**
279 * Removes all of the elements from this set.
280 */
281 public void clear() {
282 elements = 0;
283 }
284
285 /**
286 * Compares the specified object with this set for equality. Returns
287 * <tt>true</tt> if the given object is also a set, the two sets have
288 * the same size, and every member of the given set is contained in
289 * this set.
290 *
291 * @param e object to be compared for equality with this set
292 * @return <tt>true</tt> if the specified object is equal to this set
293 */
294 public boolean equals(Object o) {
295 if (!(o instanceof RegularEnumSet))
296 return super.equals(o);
297
298 RegularEnumSet es = (RegularEnumSet)o;
299 if (es.elementType != elementType)
300 return elements == 0 && es.elements == 0;
301 return es.elements == elements;
302 }
303 }