1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/rt/emul/compact/src/main/java/java/util/AbstractQueue.java Tue Feb 26 16:54:16 2013 +0100
1.3 @@ -0,0 +1,192 @@
1.4 +/*
1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.6 + *
1.7 + * This code is free software; you can redistribute it and/or modify it
1.8 + * under the terms of the GNU General Public License version 2 only, as
1.9 + * published by the Free Software Foundation. Oracle designates this
1.10 + * particular file as subject to the "Classpath" exception as provided
1.11 + * by Oracle in the LICENSE file that accompanied this code.
1.12 + *
1.13 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.14 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.15 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.16 + * version 2 for more details (a copy is included in the LICENSE file that
1.17 + * accompanied this code).
1.18 + *
1.19 + * You should have received a copy of the GNU General Public License version
1.20 + * 2 along with this work; if not, write to the Free Software Foundation,
1.21 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.22 + *
1.23 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.24 + * or visit www.oracle.com if you need additional information or have any
1.25 + * questions.
1.26 + */
1.27 +
1.28 +/*
1.29 + * This file is available under and governed by the GNU General Public
1.30 + * License version 2 only, as published by the Free Software Foundation.
1.31 + * However, the following notice accompanied the original version of this
1.32 + * file:
1.33 + *
1.34 + * Written by Doug Lea with assistance from members of JCP JSR-166
1.35 + * Expert Group and released to the public domain, as explained at
1.36 + * http://creativecommons.org/publicdomain/zero/1.0/
1.37 + */
1.38 +
1.39 +package java.util;
1.40 +
1.41 +/**
1.42 + * This class provides skeletal implementations of some {@link Queue}
1.43 + * operations. The implementations in this class are appropriate when
1.44 + * the base implementation does <em>not</em> allow <tt>null</tt>
1.45 + * elements. Methods {@link #add add}, {@link #remove remove}, and
1.46 + * {@link #element element} are based on {@link #offer offer}, {@link
1.47 + * #poll poll}, and {@link #peek peek}, respectively, but throw
1.48 + * exceptions instead of indicating failure via <tt>false</tt> or
1.49 + * <tt>null</tt> returns.
1.50 + *
1.51 + * <p>A <tt>Queue</tt> implementation that extends this class must
1.52 + * minimally define a method {@link Queue#offer} which does not permit
1.53 + * insertion of <tt>null</tt> elements, along with methods {@link
1.54 + * Queue#peek}, {@link Queue#poll}, {@link Collection#size}, and
1.55 + * {@link Collection#iterator}. Typically, additional methods will be
1.56 + * overridden as well. If these requirements cannot be met, consider
1.57 + * instead subclassing {@link AbstractCollection}.
1.58 + *
1.59 + * <p>This class is a member of the
1.60 + * <a href="{@docRoot}/../technotes/guides/collections/index.html">
1.61 + * Java Collections Framework</a>.
1.62 + *
1.63 + * @since 1.5
1.64 + * @author Doug Lea
1.65 + * @param <E> the type of elements held in this collection
1.66 + */
1.67 +public abstract class AbstractQueue<E>
1.68 + extends AbstractCollection<E>
1.69 + implements Queue<E> {
1.70 +
1.71 + /**
1.72 + * Constructor for use by subclasses.
1.73 + */
1.74 + protected AbstractQueue() {
1.75 + }
1.76 +
1.77 + /**
1.78 + * Inserts the specified element into this queue if it is possible to do so
1.79 + * immediately without violating capacity restrictions, returning
1.80 + * <tt>true</tt> upon success and throwing an <tt>IllegalStateException</tt>
1.81 + * if no space is currently available.
1.82 + *
1.83 + * <p>This implementation returns <tt>true</tt> if <tt>offer</tt> succeeds,
1.84 + * else throws an <tt>IllegalStateException</tt>.
1.85 + *
1.86 + * @param e the element to add
1.87 + * @return <tt>true</tt> (as specified by {@link Collection#add})
1.88 + * @throws IllegalStateException if the element cannot be added at this
1.89 + * time due to capacity restrictions
1.90 + * @throws ClassCastException if the class of the specified element
1.91 + * prevents it from being added to this queue
1.92 + * @throws NullPointerException if the specified element is null and
1.93 + * this queue does not permit null elements
1.94 + * @throws IllegalArgumentException if some property of this element
1.95 + * prevents it from being added to this queue
1.96 + */
1.97 + public boolean add(E e) {
1.98 + if (offer(e))
1.99 + return true;
1.100 + else
1.101 + throw new IllegalStateException("Queue full");
1.102 + }
1.103 +
1.104 + /**
1.105 + * Retrieves and removes the head of this queue. This method differs
1.106 + * from {@link #poll poll} only in that it throws an exception if this
1.107 + * queue is empty.
1.108 + *
1.109 + * <p>This implementation returns the result of <tt>poll</tt>
1.110 + * unless the queue is empty.
1.111 + *
1.112 + * @return the head of this queue
1.113 + * @throws NoSuchElementException if this queue is empty
1.114 + */
1.115 + public E remove() {
1.116 + E x = poll();
1.117 + if (x != null)
1.118 + return x;
1.119 + else
1.120 + throw new NoSuchElementException();
1.121 + }
1.122 +
1.123 + /**
1.124 + * Retrieves, but does not remove, the head of this queue. This method
1.125 + * differs from {@link #peek peek} only in that it throws an exception if
1.126 + * this queue is empty.
1.127 + *
1.128 + * <p>This implementation returns the result of <tt>peek</tt>
1.129 + * unless the queue is empty.
1.130 + *
1.131 + * @return the head of this queue
1.132 + * @throws NoSuchElementException if this queue is empty
1.133 + */
1.134 + public E element() {
1.135 + E x = peek();
1.136 + if (x != null)
1.137 + return x;
1.138 + else
1.139 + throw new NoSuchElementException();
1.140 + }
1.141 +
1.142 + /**
1.143 + * Removes all of the elements from this queue.
1.144 + * The queue will be empty after this call returns.
1.145 + *
1.146 + * <p>This implementation repeatedly invokes {@link #poll poll} until it
1.147 + * returns <tt>null</tt>.
1.148 + */
1.149 + public void clear() {
1.150 + while (poll() != null)
1.151 + ;
1.152 + }
1.153 +
1.154 + /**
1.155 + * Adds all of the elements in the specified collection to this
1.156 + * queue. Attempts to addAll of a queue to itself result in
1.157 + * <tt>IllegalArgumentException</tt>. Further, the behavior of
1.158 + * this operation is undefined if the specified collection is
1.159 + * modified while the operation is in progress.
1.160 + *
1.161 + * <p>This implementation iterates over the specified collection,
1.162 + * and adds each element returned by the iterator to this
1.163 + * queue, in turn. A runtime exception encountered while
1.164 + * trying to add an element (including, in particular, a
1.165 + * <tt>null</tt> element) may result in only some of the elements
1.166 + * having been successfully added when the associated exception is
1.167 + * thrown.
1.168 + *
1.169 + * @param c collection containing elements to be added to this queue
1.170 + * @return <tt>true</tt> if this queue changed as a result of the call
1.171 + * @throws ClassCastException if the class of an element of the specified
1.172 + * collection prevents it from being added to this queue
1.173 + * @throws NullPointerException if the specified collection contains a
1.174 + * null element and this queue does not permit null elements,
1.175 + * or if the specified collection is null
1.176 + * @throws IllegalArgumentException if some property of an element of the
1.177 + * specified collection prevents it from being added to this
1.178 + * queue, or if the specified collection is this queue
1.179 + * @throws IllegalStateException if not all the elements can be added at
1.180 + * this time due to insertion restrictions
1.181 + * @see #add(Object)
1.182 + */
1.183 + public boolean addAll(Collection<? extends E> c) {
1.184 + if (c == null)
1.185 + throw new NullPointerException();
1.186 + if (c == this)
1.187 + throw new IllegalArgumentException();
1.188 + boolean modified = false;
1.189 + for (E e : c)
1.190 + if (add(e))
1.191 + modified = true;
1.192 + return modified;
1.193 + }
1.194 +
1.195 +}