/* * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.util; /** * Private implementation class for EnumSet, for "regular sized" enum types * (i.e., those with 64 or fewer enum constants). * * @author Josh Bloch * @since 1.5 * @serial exclude */ class RegularEnumSet> extends EnumSet { /** * Bit vector representation of this set. The 2^k bit indicates the * presence of universe[k] in this set. */ private long elements = 0L; RegularEnumSet(ClasselementType, Enum[] universe) { super(elementType, universe); } void addRange(E from, E to) { elements = (-1L >>> (from.ordinal() - to.ordinal() - 1)) << from.ordinal(); } void addAll() { if (universe.length != 0) elements = -1L >>> -universe.length; } void complement() { if (universe.length != 0) { elements = ~elements; elements &= -1L >>> -universe.length; // Mask unused bits } } /** * Returns an iterator over the elements contained in this set. The * iterator traverses the elements in their natural order (which is * the order in which the enum constants are declared). The returned * Iterator is a "snapshot" iterator that will never throw {@link * ConcurrentModificationException}; the elements are traversed as they * existed when this call was invoked. * * @return an iterator over the elements contained in this set */ public Iterator iterator() { return new EnumSetIterator<>(); } private class EnumSetIterator> implements Iterator { /** * A bit vector representing the elements in the set not yet * returned by this iterator. */ long unseen; /** * The bit representing the last element returned by this iterator * but not removed, or zero if no such element exists. */ long lastReturned = 0; EnumSetIterator() { unseen = elements; } public boolean hasNext() { return unseen != 0; } public E next() { if (unseen == 0) throw new NoSuchElementException(); lastReturned = unseen & -unseen; unseen -= lastReturned; return (E) universe[Long.numberOfTrailingZeros(lastReturned)]; } public void remove() { if (lastReturned == 0) throw new IllegalStateException(); elements -= lastReturned; lastReturned = 0; } } /** * Returns the number of elements in this set. * * @return the number of elements in this set */ public int size() { return Long.bitCount(elements); } /** * Returns true if this set contains no elements. * * @return true if this set contains no elements */ public boolean isEmpty() { return elements == 0; } /** * Returns true if this set contains the specified element. * * @param e element to be checked for containment in this collection * @return true if this set contains the specified element */ public boolean contains(Object e) { if (e == null) return false; Class eClass = e.getClass(); if (eClass != elementType && eClass.getSuperclass() != elementType) return false; return (elements & (1L << ((Enum)e).ordinal())) != 0; } // Modification Operations /** * Adds the specified element to this set if it is not already present. * * @param e element to be added to this set * @return true if the set changed as a result of the call * * @throws NullPointerException if e is null */ public boolean add(E e) { typeCheck(e); long oldElements = elements; elements |= (1L << ((Enum)e).ordinal()); return elements != oldElements; } /** * Removes the specified element from this set if it is present. * * @param e element to be removed from this set, if present * @return true if the set contained the specified element */ public boolean remove(Object e) { if (e == null) return false; Class eClass = e.getClass(); if (eClass != elementType && eClass.getSuperclass() != elementType) return false; long oldElements = elements; elements &= ~(1L << ((Enum)e).ordinal()); return elements != oldElements; } // Bulk Operations /** * Returns true if this set contains all of the elements * in the specified collection. * * @param c collection to be checked for containment in this set * @return true if this set contains all of the elements * in the specified collection * @throws NullPointerException if the specified collection is null */ public boolean containsAll(Collection c) { if (!(c instanceof RegularEnumSet)) return super.containsAll(c); RegularEnumSet es = (RegularEnumSet)c; if (es.elementType != elementType) return es.isEmpty(); return (es.elements & ~elements) == 0; } /** * Adds all of the elements in the specified collection to this set. * * @param c collection whose elements are to be added to this set * @return true if this set changed as a result of the call * @throws NullPointerException if the specified collection or any * of its elements are null */ public boolean addAll(Collection c) { if (!(c instanceof RegularEnumSet)) return super.addAll(c); RegularEnumSet es = (RegularEnumSet)c; if (es.elementType != elementType) { if (es.isEmpty()) return false; else throw new ClassCastException( es.elementType + " != " + elementType); } long oldElements = elements; elements |= es.elements; return elements != oldElements; } /** * Removes from this set all of its elements that are contained in * the specified collection. * * @param c elements to be removed from this set * @return true if this set changed as a result of the call * @throws NullPointerException if the specified collection is null */ public boolean removeAll(Collection c) { if (!(c instanceof RegularEnumSet)) return super.removeAll(c); RegularEnumSet es = (RegularEnumSet)c; if (es.elementType != elementType) return false; long oldElements = elements; elements &= ~es.elements; return elements != oldElements; } /** * Retains only the elements in this set that are contained in the * specified collection. * * @param c elements to be retained in this set * @return true if this set changed as a result of the call * @throws NullPointerException if the specified collection is null */ public boolean retainAll(Collection c) { if (!(c instanceof RegularEnumSet)) return super.retainAll(c); RegularEnumSet es = (RegularEnumSet)c; if (es.elementType != elementType) { boolean changed = (elements != 0); elements = 0; return changed; } long oldElements = elements; elements &= es.elements; return elements != oldElements; } /** * Removes all of the elements from this set. */ public void clear() { elements = 0; } /** * Compares the specified object with this set for equality. Returns * true if the given object is also a set, the two sets have * the same size, and every member of the given set is contained in * this set. * * @param e object to be compared for equality with this set * @return true if the specified object is equal to this set */ public boolean equals(Object o) { if (!(o instanceof RegularEnumSet)) return super.equals(o); RegularEnumSet es = (RegularEnumSet)o; if (es.elementType != elementType) return elements == 0 && es.elements == 0; return es.elements == elements; } }