1.1 --- a/emul/compact/src/main/java/java/util/AbstractSet.java Mon Feb 25 19:00:08 2013 +0100
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,185 +0,0 @@
1.4 -/*
1.5 - * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
1.6 - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 - *
1.8 - * This code is free software; you can redistribute it and/or modify it
1.9 - * under the terms of the GNU General Public License version 2 only, as
1.10 - * published by the Free Software Foundation. Oracle designates this
1.11 - * particular file as subject to the "Classpath" exception as provided
1.12 - * by Oracle in the LICENSE file that accompanied this code.
1.13 - *
1.14 - * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 - * version 2 for more details (a copy is included in the LICENSE file that
1.18 - * accompanied this code).
1.19 - *
1.20 - * You should have received a copy of the GNU General Public License version
1.21 - * 2 along with this work; if not, write to the Free Software Foundation,
1.22 - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 - *
1.24 - * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 - * or visit www.oracle.com if you need additional information or have any
1.26 - * questions.
1.27 - */
1.28 -
1.29 -package java.util;
1.30 -
1.31 -/**
1.32 - * This class provides a skeletal implementation of the <tt>Set</tt>
1.33 - * interface to minimize the effort required to implement this
1.34 - * interface. <p>
1.35 - *
1.36 - * The process of implementing a set by extending this class is identical
1.37 - * to that of implementing a Collection by extending AbstractCollection,
1.38 - * except that all of the methods and constructors in subclasses of this
1.39 - * class must obey the additional constraints imposed by the <tt>Set</tt>
1.40 - * interface (for instance, the add method must not permit addition of
1.41 - * multiple instances of an object to a set).<p>
1.42 - *
1.43 - * Note that this class does not override any of the implementations from
1.44 - * the <tt>AbstractCollection</tt> class. It merely adds implementations
1.45 - * for <tt>equals</tt> and <tt>hashCode</tt>.<p>
1.46 - *
1.47 - * This class is a member of the
1.48 - * <a href="{@docRoot}/../technotes/guides/collections/index.html">
1.49 - * Java Collections Framework</a>.
1.50 - *
1.51 - * @param <E> the type of elements maintained by this set
1.52 - *
1.53 - * @author Josh Bloch
1.54 - * @author Neal Gafter
1.55 - * @see Collection
1.56 - * @see AbstractCollection
1.57 - * @see Set
1.58 - * @since 1.2
1.59 - */
1.60 -
1.61 -public abstract class AbstractSet<E> extends AbstractCollection<E> implements Set<E> {
1.62 - /**
1.63 - * Sole constructor. (For invocation by subclass constructors, typically
1.64 - * implicit.)
1.65 - */
1.66 - protected AbstractSet() {
1.67 - }
1.68 -
1.69 - // Comparison and hashing
1.70 -
1.71 - /**
1.72 - * Compares the specified object with this set for equality. Returns
1.73 - * <tt>true</tt> if the given object is also a set, the two sets have
1.74 - * the same size, and every member of the given set is contained in
1.75 - * this set. This ensures that the <tt>equals</tt> method works
1.76 - * properly across different implementations of the <tt>Set</tt>
1.77 - * interface.<p>
1.78 - *
1.79 - * This implementation first checks if the specified object is this
1.80 - * set; if so it returns <tt>true</tt>. Then, it checks if the
1.81 - * specified object is a set whose size is identical to the size of
1.82 - * this set; if not, it returns false. If so, it returns
1.83 - * <tt>containsAll((Collection) o)</tt>.
1.84 - *
1.85 - * @param o object to be compared for equality with this set
1.86 - * @return <tt>true</tt> if the specified object is equal to this set
1.87 - */
1.88 - public boolean equals(Object o) {
1.89 - if (o == this)
1.90 - return true;
1.91 -
1.92 - if (!(o instanceof Set))
1.93 - return false;
1.94 - Collection c = (Collection) o;
1.95 - if (c.size() != size())
1.96 - return false;
1.97 - try {
1.98 - return containsAll(c);
1.99 - } catch (ClassCastException unused) {
1.100 - return false;
1.101 - } catch (NullPointerException unused) {
1.102 - return false;
1.103 - }
1.104 - }
1.105 -
1.106 - /**
1.107 - * Returns the hash code value for this set. The hash code of a set is
1.108 - * defined to be the sum of the hash codes of the elements in the set,
1.109 - * where the hash code of a <tt>null</tt> element is defined to be zero.
1.110 - * This ensures that <tt>s1.equals(s2)</tt> implies that
1.111 - * <tt>s1.hashCode()==s2.hashCode()</tt> for any two sets <tt>s1</tt>
1.112 - * and <tt>s2</tt>, as required by the general contract of
1.113 - * {@link Object#hashCode}.
1.114 - *
1.115 - * <p>This implementation iterates over the set, calling the
1.116 - * <tt>hashCode</tt> method on each element in the set, and adding up
1.117 - * the results.
1.118 - *
1.119 - * @return the hash code value for this set
1.120 - * @see Object#equals(Object)
1.121 - * @see Set#equals(Object)
1.122 - */
1.123 - public int hashCode() {
1.124 - int h = 0;
1.125 - Iterator<E> i = iterator();
1.126 - while (i.hasNext()) {
1.127 - E obj = i.next();
1.128 - if (obj != null)
1.129 - h += obj.hashCode();
1.130 - }
1.131 - return h;
1.132 - }
1.133 -
1.134 - /**
1.135 - * Removes from this set all of its elements that are contained in the
1.136 - * specified collection (optional operation). If the specified
1.137 - * collection is also a set, this operation effectively modifies this
1.138 - * set so that its value is the <i>asymmetric set difference</i> of
1.139 - * the two sets.
1.140 - *
1.141 - * <p>This implementation determines which is the smaller of this set
1.142 - * and the specified collection, by invoking the <tt>size</tt>
1.143 - * method on each. If this set has fewer elements, then the
1.144 - * implementation iterates over this set, checking each element
1.145 - * returned by the iterator in turn to see if it is contained in
1.146 - * the specified collection. If it is so contained, it is removed
1.147 - * from this set with the iterator's <tt>remove</tt> method. If
1.148 - * the specified collection has fewer elements, then the
1.149 - * implementation iterates over the specified collection, removing
1.150 - * from this set each element returned by the iterator, using this
1.151 - * set's <tt>remove</tt> method.
1.152 - *
1.153 - * <p>Note that this implementation will throw an
1.154 - * <tt>UnsupportedOperationException</tt> if the iterator returned by the
1.155 - * <tt>iterator</tt> method does not implement the <tt>remove</tt> method.
1.156 - *
1.157 - * @param c collection containing elements to be removed from this set
1.158 - * @return <tt>true</tt> if this set changed as a result of the call
1.159 - * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
1.160 - * is not supported by this set
1.161 - * @throws ClassCastException if the class of an element of this set
1.162 - * is incompatible with the specified collection
1.163 - * (<a href="Collection.html#optional-restrictions">optional</a>)
1.164 - * @throws NullPointerException if this set contains a null element and the
1.165 - * specified collection does not permit null elements
1.166 - * (<a href="Collection.html#optional-restrictions">optional</a>),
1.167 - * or if the specified collection is null
1.168 - * @see #remove(Object)
1.169 - * @see #contains(Object)
1.170 - */
1.171 - public boolean removeAll(Collection<?> c) {
1.172 - boolean modified = false;
1.173 -
1.174 - if (size() > c.size()) {
1.175 - for (Iterator<?> i = c.iterator(); i.hasNext(); )
1.176 - modified |= remove(i.next());
1.177 - } else {
1.178 - for (Iterator<?> i = iterator(); i.hasNext(); ) {
1.179 - if (c.contains(i.next())) {
1.180 - i.remove();
1.181 - modified = true;
1.182 - }
1.183 - }
1.184 - }
1.185 - return modified;
1.186 - }
1.187 -
1.188 -}