1 /* 2 * Copyright (c) 2003, 2011, 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 RegularEnumSet(Class<E>elementType, Enum[] universe)44 RegularEnumSet(Class<E>elementType, Enum[] universe) { 45 super(elementType, universe); 46 } 47 addRange(E from, E to)48 void addRange(E from, E to) { 49 elements = (-1L >>> (from.ordinal() - to.ordinal() - 1)) << from.ordinal(); 50 } 51 addAll()52 void addAll() { 53 if (universe.length != 0) 54 elements = -1L >>> -universe.length; 55 } 56 complement()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 */ iterator()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 EnumSetIterator()91 EnumSetIterator() { 92 unseen = elements; 93 } 94 hasNext()95 public boolean hasNext() { 96 return unseen != 0; 97 } 98 next()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 remove()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 */ size()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 */ isEmpty()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 */ contains(Object e)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 */ add(E e)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 */ remove(Object e)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 */ containsAll(Collection<?> c)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 */ addAll(Collection<? extends E> c)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 */ removeAll(Collection<?> c)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 */ retainAll(Collection<?> c)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 */ clear()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 */ equals(Object o)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 } 304