1adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/* 229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This code is free software; you can redistribute it and/or modify it 529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * under the terms of the GNU General Public License version 2 only, as 629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * published by the Free Software Foundation. Oracle designates this 729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * particular file as subject to the "Classpath" exception as provided 829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * by Oracle in the LICENSE file that accompanied this code. 929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 1029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This code is distributed in the hope that it will be useful, but WITHOUT 1129957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * version 2 for more details (a copy is included in the LICENSE file that 1429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * accompanied this code). 1529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 1629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * You should have received a copy of the GNU General Public License version 1729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 2 along with this work; if not, write to the Free Software Foundation, 1829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 2029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2129957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * or visit www.oracle.com if you need additional information or have any 2229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * questions. 2329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer */ 2429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer 2529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer/* 2629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This file is available under and governed by the GNU General Public 2729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * License version 2 only, as published by the Free Software Foundation. 2829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * However, the following notice accompanied the original version of this 2929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * file: 3029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 31adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Written by Doug Lea with assistance from members of JCP JSR-166 32adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Expert Group and released to the public domain, as explained at 33a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * http://creativecommons.org/publicdomain/zero/1.0/ 34adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 35adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 36adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Projectpackage java.util.concurrent; 37adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 38b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.AbstractQueue; 39b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Arrays; 40b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Collection; 41b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Comparator; 42b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Iterator; 43b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.NoSuchElementException; 44b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.PriorityQueue; 45b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Queue; 46b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.SortedSet; 47b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.Spliterator; 4891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravleimport java.util.concurrent.locks.Condition; 4991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravleimport java.util.concurrent.locks.ReentrantLock; 50b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.util.function.Consumer; 51adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 52adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project// BEGIN android-note 53adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project// removed link to collections framework docs 54adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project// END android-note 55adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 56adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/** 57adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * An unbounded {@linkplain BlockingQueue blocking queue} that uses 58adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * the same ordering rules as class {@link PriorityQueue} and supplies 59adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * blocking retrieval operations. While this queue is logically 60adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * unbounded, attempted additions may fail due to resource exhaustion 618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * (causing {@code OutOfMemoryError}). This class does not permit 628eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code null} elements. A priority queue relying on {@linkplain 63bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Comparable natural ordering} also does not permit insertion of 64bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * non-comparable objects (doing so results in 658eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code ClassCastException}). 66adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 67bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * <p>This class and its iterator implement all of the 68bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * <em>optional</em> methods of the {@link Collection} and {@link 69bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Iterator} interfaces. The Iterator provided in method {@link 70bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * #iterator()} is <em>not</em> guaranteed to traverse the elements of 71bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * the PriorityBlockingQueue in any particular order. If you need 72bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * ordered traversal, consider using 738eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code Arrays.sort(pq.toArray())}. Also, method {@code drainTo} 74bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * can be used to <em>remove</em> some or all elements in priority 75bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * order and place them in another collection. 76bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 77bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * <p>Operations on this class make no guarantees about the ordering 78bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * of elements with equal priority. If you need to enforce an 79bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * ordering, you can define custom classes or comparators that use a 80bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * secondary key to break ties in primary priority values. For 81bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * example, here is a class that applies first-in-first-out 82bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * tie-breaking to comparable elements. To use it, you would insert a 838eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code new FIFOEntry(anEntry)} instead of a plain entry object. 84bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 85b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <pre> {@code 868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * class FIFOEntry<E extends Comparable<? super E>> 878eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * implements Comparable<FIFOEntry<E>> { 888eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * static final AtomicLong seq = new AtomicLong(0); 89bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * final long seqNum; 90bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * final E entry; 91bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * public FIFOEntry(E entry) { 92bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * seqNum = seq.getAndIncrement(); 93bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * this.entry = entry; 94bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * } 95bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * public E getEntry() { return entry; } 968eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * public int compareTo(FIFOEntry<E> other) { 97bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * int res = entry.compareTo(other.entry); 988eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * if (res == 0 && other.entry != this.entry) 998eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * res = (seqNum < other.seqNum ? -1 : 1); 100bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * return res; 101bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * } 1028eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * }}</pre> 103adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 104adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @since 1.5 105adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @author Doug Lea 106b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param <E> the type of elements held in this queue 107adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 10891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle@SuppressWarnings("unchecked") 109adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Projectpublic class PriorityBlockingQueue<E> extends AbstractQueue<E> 110adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project implements BlockingQueue<E>, java.io.Serializable { 111adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private static final long serialVersionUID = 5595510919245408276L; 112adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 1138eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /* 1148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * The implementation uses an array-based binary heap, with public 1158eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * operations protected with a single lock. However, allocation 1168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * during resizing uses a simple spinlock (used only while not 1178eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * holding main lock) in order to allow takes to operate 1188eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * concurrently with allocation. This avoids repeated 1198eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * postponement of waiting consumers and consequent element 1208eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * build-up. The need to back away from lock during allocation 1218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * makes it impossible to simply wrap delegated 1228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * java.util.PriorityQueue operations within a lock, as was done 1238eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * in a previous version of this class. To maintain 1248eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * interoperability, a plain PriorityQueue is still used during 125a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * serialization, which maintains compatibility at the expense of 1268eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * transiently doubling overhead. 1278eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1288eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1298eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Default array capacity. 1318eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static final int DEFAULT_INITIAL_CAPACITY = 11; 1338eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1348eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1358eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * The maximum size of array to allocate. 1368eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Some VMs reserve some header words in an array. 1378eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Attempts to allocate larger arrays may result in 1388eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * OutOfMemoryError: Requested array size exceeds VM limit 1398eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1408eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; 1418eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1428eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1438eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Priority queue represented as a balanced binary heap: the two 1448eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * children of queue[n] are queue[2*n+1] and queue[2*(n+1)]. The 1458eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * priority queue is ordered by comparator, or by the elements' 1468eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * natural ordering, if comparator is null: For each node n in the 1478eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * heap and each descendant d of n, n <= d. The element with the 1488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * lowest value is in queue[0], assuming the queue is nonempty. 1498eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1508eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private transient Object[] queue; 1518eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1528eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1538eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * The number of elements in the priority queue. 1548eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1558eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private transient int size; 1568eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1578eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1588eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * The comparator, or null if priority queue uses elements' 1598eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * natural ordering. 1608eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private transient Comparator<? super E> comparator; 162adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 163adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 164b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Lock used for all public operations. 1658eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1668eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private final ReentrantLock lock; 1678eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1688eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 169b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Condition for blocking when empty. 1708eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1718eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private final Condition notEmpty; 1728eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1738eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1748eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Spinlock for allocation, acquired via CAS. 1758eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 1768eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private transient volatile int allocationSpinLock; 1778eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1788eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1798eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * A plain PriorityQueue used only for serialization, 1808eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * to maintain compatibility with previous versions 1818eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * of this class. Non-null only during serialization/deserialization. 1828eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 183a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private PriorityQueue<E> q; 1848eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 1858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 1868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Creates a {@code PriorityBlockingQueue} with the default 187bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * initial capacity (11) that orders its elements according to 188bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * their {@linkplain Comparable natural ordering}. 189adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 190adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public PriorityBlockingQueue() { 1918eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this(DEFAULT_INITIAL_CAPACITY, null); 192adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 193adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 194adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 1958eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Creates a {@code PriorityBlockingQueue} with the specified 196bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * initial capacity that orders its elements according to their 197bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * {@linkplain Comparable natural ordering}. 198adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 199bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param initialCapacity the initial capacity for this priority queue 2008eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @throws IllegalArgumentException if {@code initialCapacity} is less 201bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * than 1 202adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 203adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public PriorityBlockingQueue(int initialCapacity) { 2048eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this(initialCapacity, null); 205adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 206adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 207adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 2088eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Creates a {@code PriorityBlockingQueue} with the specified initial 209bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * capacity that orders its elements according to the specified 210bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * comparator. 211adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 212bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param initialCapacity the initial capacity for this priority queue 213bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param comparator the comparator that will be used to order this 214bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue. If {@code null}, the {@linkplain Comparable 215bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * natural ordering} of the elements will be used. 2168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @throws IllegalArgumentException if {@code initialCapacity} is less 217bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * than 1 218adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 219adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public PriorityBlockingQueue(int initialCapacity, 220adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project Comparator<? super E> comparator) { 2218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (initialCapacity < 1) 2228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson throw new IllegalArgumentException(); 2238eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.lock = new ReentrantLock(); 2248eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.notEmpty = lock.newCondition(); 2258eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.comparator = comparator; 2268eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.queue = new Object[initialCapacity]; 227adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 228adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 229adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 2308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Creates a {@code PriorityBlockingQueue} containing the elements 231bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * in the specified collection. If the specified collection is a 232edf43d27e240d82106f39ae91404963c23987234Narayan Kamath * {@link SortedSet} or a {@link PriorityQueue}, this 233bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue will be ordered according to the same ordering. 234bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Otherwise, this priority queue will be ordered according to the 235bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * {@linkplain Comparable natural ordering} of its elements. 236adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 237bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param c the collection whose elements are to be placed 238bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * into this priority queue 239adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @throws ClassCastException if elements of the specified collection 240adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * cannot be compared to one another according to the priority 241bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * queue's ordering 242bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified collection or any 243bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * of its elements are null 244adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 245adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public PriorityBlockingQueue(Collection<? extends E> c) { 2468eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.lock = new ReentrantLock(); 2478eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.notEmpty = lock.newCondition(); 2488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson boolean heapify = true; // true if not known to be in heap order 2498eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson boolean screen = true; // true if must screen for nulls 2508eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (c instanceof SortedSet<?>) { 2518eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson SortedSet<? extends E> ss = (SortedSet<? extends E>) c; 2528eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.comparator = (Comparator<? super E>) ss.comparator(); 2538eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson heapify = false; 2548eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 2558eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else if (c instanceof PriorityBlockingQueue<?>) { 2568eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson PriorityBlockingQueue<? extends E> pq = 2578eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson (PriorityBlockingQueue<? extends E>) c; 2588eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.comparator = (Comparator<? super E>) pq.comparator(); 2598eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson screen = false; 2608eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (pq.getClass() == PriorityBlockingQueue.class) // exact match 2618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson heapify = false; 2628eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 2638eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] a = c.toArray(); 2648eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = a.length; 2658eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson // If c.toArray incorrectly doesn't return Object[], copy it. 2668eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (a.getClass() != Object[].class) 2678eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson a = Arrays.copyOf(a, n, Object[].class); 2688eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (screen && (n == 1 || this.comparator != null)) { 2698eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson for (int i = 0; i < n; ++i) 2708eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (a[i] == null) 2718eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson throw new NullPointerException(); 2728eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 2738eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.queue = a; 2748eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.size = n; 2758eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (heapify) 2768eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson heapify(); 2778eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 2788eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 2798eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 2808eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Tries to grow array to accommodate at least one more element 2818eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * (but normally expand by about 50%), giving up (allowing retry) 2828eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * on contention (which we expect to be rare). Call only while 2838eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * holding lock. 2848eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * 2858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param array the heap array 2868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param oldCap the length of the array 2878eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 2888eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private void tryGrow(Object[] array, int oldCap) { 2898eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson lock.unlock(); // must release and then re-acquire main lock 2908eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] newArray = null; 2918eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (allocationSpinLock == 0 && 292b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak U.compareAndSwapInt(this, ALLOCATIONSPINLOCK, 0, 1)) { 2938eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson try { 2948eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int newCap = oldCap + ((oldCap < 64) ? 2958eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson (oldCap + 2) : // grow faster if small 2968eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson (oldCap >> 1)); 2978eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (newCap - MAX_ARRAY_SIZE > 0) { // possible overflow 2988eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int minCap = oldCap + 1; 2998eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (minCap < 0 || minCap > MAX_ARRAY_SIZE) 3008eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson throw new OutOfMemoryError(); 3018eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson newCap = MAX_ARRAY_SIZE; 3028eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3038eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (newCap > oldCap && queue == array) 3048eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson newArray = new Object[newCap]; 3058eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } finally { 3068eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson allocationSpinLock = 0; 3078eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3088eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3098eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (newArray == null) // back off if another thread is allocating 3108eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Thread.yield(); 3118eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson lock.lock(); 3128eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (newArray != null && queue == array) { 3138eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson queue = newArray; 3148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson System.arraycopy(array, 0, newArray, 0, oldCap); 3158eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3178eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 3188eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 3198eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Mechanics for poll(). Call only while holding lock. 3208eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 321a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private E dequeue() { 3228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size - 1; 3238eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (n < 0) 324a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return null; 3258eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else { 3268eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 327a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson E result = (E) array[0]; 3288eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson E x = (E) array[n]; 3298eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[n] = null; 3308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super E> cmp = comparator; 3318eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp == null) 3328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownComparable(0, x, array, n); 3338eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else 3348eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownUsingComparator(0, x, array, n, cmp); 3358eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson size = n; 336a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return result; 3378eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3388eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3398eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 3408eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 3418eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Inserts item x at position k, maintaining heap invariant by 3428eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * promoting x up the tree until it is greater than or equal to 3438eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * its parent, or is the root. 3448eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * 3458eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * To simplify and speed up coercions and comparisons. the 3468eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Comparable and Comparator versions are separated into different 3478eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * methods that are otherwise identical. (Similarly for siftDown.) 3488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * These methods are static, with heap state as arguments, to 3498eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * simplify use in light of possible comparator exceptions. 3508eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * 3518eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param k the position to fill 3528eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param x the item to insert 3538eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param array the heap array 3548eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 3558eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static <T> void siftUpComparable(int k, T x, Object[] array) { 3568eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparable<? super T> key = (Comparable<? super T>) x; 3578eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson while (k > 0) { 3588eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int parent = (k - 1) >>> 1; 3598eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object e = array[parent]; 3608eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (key.compareTo((T) e) >= 0) 3618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson break; 3628eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[k] = e; 3638eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson k = parent; 3648eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3658eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[k] = key; 3668eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3678eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 3688eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static <T> void siftUpUsingComparator(int k, T x, Object[] array, 3698eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super T> cmp) { 3708eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson while (k > 0) { 3718eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int parent = (k - 1) >>> 1; 3728eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object e = array[parent]; 3738eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp.compare(x, (T) e) >= 0) 3748eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson break; 3758eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[k] = e; 3768eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson k = parent; 3778eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3788eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[k] = x; 3798eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 3808eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 3818eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 3828eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Inserts item x at position k, maintaining heap invariant by 3838eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * demoting x down the tree repeatedly until it is less than or 3848eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * equal to its children or is a leaf. 3858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * 3868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param k the position to fill 3878eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param x the item to insert 3888eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param array the heap array 3898eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @param n heap size 3908eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 3918eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static <T> void siftDownComparable(int k, T x, Object[] array, 3928eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n) { 39391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (n > 0) { 39491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Comparable<? super T> key = (Comparable<? super T>)x; 39591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int half = n >>> 1; // loop while a non-leaf 39691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle while (k < half) { 39791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int child = (k << 1) + 1; // assume left child is least 39891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Object c = array[child]; 39991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int right = child + 1; 40091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (right < n && 40191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((Comparable<? super T>) c).compareTo((T) array[right]) > 0) 40291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle c = array[child = right]; 40391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (key.compareTo((T) c) <= 0) 40491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle break; 40591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle array[k] = c; 40691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle k = child; 40791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 40891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle array[k] = key; 4098eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 4108eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 4118eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 4128eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private static <T> void siftDownUsingComparator(int k, T x, Object[] array, 4138eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n, 4148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super T> cmp) { 41591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (n > 0) { 41691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int half = n >>> 1; 41791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle while (k < half) { 41891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int child = (k << 1) + 1; 41991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Object c = array[child]; 42091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int right = child + 1; 42191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (right < n && cmp.compare((T) c, (T) array[right]) > 0) 42291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle c = array[child = right]; 42391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (cmp.compare(x, (T) c) <= 0) 42491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle break; 42591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle array[k] = c; 42691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle k = child; 42791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 42891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle array[k] = x; 4298eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 4308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 4318eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 4328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 4338eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Establishes the heap invariant (described above) in the entire tree, 4348eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * assuming nothing about the order of the elements prior to the call. 4358eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 4368eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private void heapify() { 4378eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 4388eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size; 4398eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int half = (n >>> 1) - 1; 4408eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super E> cmp = comparator; 4418eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp == null) { 4428eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson for (int i = half; i >= 0; i--) 4438eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownComparable(i, (E) array[i], array, n); 4448eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 4458eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else { 4468eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson for (int i = half; i >= 0; i--) 4478eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownUsingComparator(i, (E) array[i], array, n, cmp); 4488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 449adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 450adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 451adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 452bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Inserts the specified element into this priority queue. 453adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 454bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param e the element to add 4558eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code true} (as specified by {@link Collection#add}) 456adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @throws ClassCastException if the specified element cannot be compared 457bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * with elements currently in the priority queue according to the 458bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue's ordering 459bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified element is null 460adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 461bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public boolean add(E e) { 462bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson return offer(e); 463adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 464adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 465adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 466adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Inserts the specified element into this priority queue. 4678eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * As the queue is unbounded, this method will never return {@code false}. 468adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 469bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param e the element to add 4708eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code true} (as specified by {@link Queue#offer}) 471adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @throws ClassCastException if the specified element cannot be compared 472bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * with elements currently in the priority queue according to the 473bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue's ordering 474bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified element is null 475adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 476bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public boolean offer(E e) { 4778eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (e == null) 4788eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson throw new NullPointerException(); 479adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 480adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 4818eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n, cap; 4828eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array; 4838eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson while ((n = size) >= (cap = (array = queue).length)) 4848eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson tryGrow(array, cap); 485adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 4868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super E> cmp = comparator; 4878eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp == null) 4888eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftUpComparable(n, e, array); 4898eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else 4908eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftUpUsingComparator(n, e, array, cmp); 4918eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson size = n + 1; 492adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project notEmpty.signal(); 493adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 494adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 495adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 4968eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return true; 497adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 498adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 499adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 5008eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Inserts the specified element into this priority queue. 5018eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * As the queue is unbounded, this method will never block. 502bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 503bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param e the element to add 504bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws ClassCastException if the specified element cannot be compared 505bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * with elements currently in the priority queue according to the 506bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue's ordering 507bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified element is null 508adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 509bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public void put(E e) { 510bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson offer(e); // never need to block 511adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 512adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 513adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 5148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Inserts the specified element into this priority queue. 5158eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * As the queue is unbounded, this method will never block or 5168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * return {@code false}. 517bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 518bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param e the element to add 519adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param timeout This parameter is ignored as the method never blocks 520adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param unit This parameter is ignored as the method never blocks 5218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code true} (as specified by 522a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link BlockingQueue#offer(Object,long,TimeUnit) BlockingQueue.offer}) 523bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws ClassCastException if the specified element cannot be compared 524bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * with elements currently in the priority queue according to the 525bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * priority queue's ordering 526bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified element is null 527adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 528bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public boolean offer(E e, long timeout, TimeUnit unit) { 529bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson return offer(e); // never need to block 530bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson } 531bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson 532bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public E poll() { 533bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson final ReentrantLock lock = this.lock; 534bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson lock.lock(); 535bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson try { 536a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return dequeue(); 537bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson } finally { 538bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson lock.unlock(); 539bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson } 540adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 541adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 542adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public E take() throws InterruptedException { 543adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 544adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lockInterruptibly(); 5458eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson E result; 546adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 547a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while ( (result = dequeue()) == null) 5488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson notEmpty.await(); 549adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 550adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 551adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 5528eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return result; 553adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 554adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 555adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public E poll(long timeout, TimeUnit unit) throws InterruptedException { 556adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project long nanos = unit.toNanos(timeout); 557adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 558adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lockInterruptibly(); 5598eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson E result; 560adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 561a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while ( (result = dequeue()) == null && nanos > 0) 5628eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson nanos = notEmpty.awaitNanos(nanos); 563adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 564adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 565adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 5668eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return result; 567adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 568adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 569adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public E peek() { 570adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 571adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 572adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 573a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return (size == 0) ? null : (E) queue[0]; 574adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 575adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 576adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 577adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 578adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 579bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 580bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Returns the comparator used to order the elements in this queue, 5818eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * or {@code null} if this queue uses the {@linkplain Comparable 582bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * natural ordering} of its elements. 583bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 584bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @return the comparator used to order the elements in this queue, 5858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * or {@code null} if this queue uses the natural 586bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * ordering of its elements 587bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 588bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson public Comparator<? super E> comparator() { 5898eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return comparator; 590bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson } 591bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson 592adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public int size() { 593adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 594adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 595adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 5968eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return size; 597adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 598adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 599adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 600adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 601adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 602adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 6038eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Always returns {@code Integer.MAX_VALUE} because 6048eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * a {@code PriorityBlockingQueue} is not capacity constrained. 6058eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code Integer.MAX_VALUE} always 606adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 607adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public int remainingCapacity() { 608adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return Integer.MAX_VALUE; 609adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 610adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 6118eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private int indexOf(Object o) { 6128eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (o != null) { 6138eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 6148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size; 6158eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson for (int i = 0; i < n; i++) 6168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (o.equals(array[i])) 6178eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return i; 6188eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6198eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return -1; 6208eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 6228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 6238eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Removes the ith element from queue. 6248eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 6258eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private void removeAt(int i) { 6268eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 6278eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size - 1; 6288eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (n == i) // removed last element 6298eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[i] = null; 6308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else { 6318eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson E moved = (E) array[n]; 6328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[n] = null; 6338eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Comparator<? super E> cmp = comparator; 6348eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp == null) 6358eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownComparable(i, moved, array, n); 6368eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else 6378eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftDownUsingComparator(i, moved, array, n, cmp); 6388eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (array[i] == moved) { 6398eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (cmp == null) 6408eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftUpComparable(i, moved, array); 6418eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson else 6428eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson siftUpUsingComparator(i, moved, array, cmp); 6438eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6448eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6458eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson size = n; 6468eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6478eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 648bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 649bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Removes a single instance of the specified element from this queue, 650bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * if it is present. More formally, removes an element {@code e} such 651bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * that {@code o.equals(e)}, if this queue contains one or more such 652bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * elements. Returns {@code true} if and only if this queue contained 653bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * the specified element (or equivalently, if this queue changed as a 654bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * result of the call). 655bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 656bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param o element to be removed from this queue, if present 6578eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code true} if this queue changed as a result of the call 658bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 659adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public boolean remove(Object o) { 660adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 661adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 662adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 6638eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int i = indexOf(o); 664a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (i == -1) 665a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return false; 666a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson removeAt(i); 667a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return true; 6688eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } finally { 6698eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson lock.unlock(); 6708eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6718eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6728eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 6738eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 674b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Identity-based version for use in Itr.remove. 6758eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 676a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson void removeEQ(Object o) { 6778eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson final ReentrantLock lock = this.lock; 6788eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson lock.lock(); 6798eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson try { 6808eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 681a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 0, n = size; i < n; i++) { 6828eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (o == array[i]) { 6838eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson removeAt(i); 6848eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson break; 6858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 6868eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 687adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 688adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 689adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 690adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 691adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 692bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 693bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Returns {@code true} if this queue contains the specified element. 694bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * More formally, returns {@code true} if and only if this queue contains 695bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * at least one element {@code e} such that {@code o.equals(e)}. 696bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 697bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param o object to be checked for containment in this queue 6988eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * @return {@code true} if this queue contains the specified element 699bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 700adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public boolean contains(Object o) { 701adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 702adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 703adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 704a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return indexOf(o) != -1; 705adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 706adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 707adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 708adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 709adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 710adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public String toString() { 711b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return Helpers.collectionToString(this); 712adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 713adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 714bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 715bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws UnsupportedOperationException {@inheritDoc} 716bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws ClassCastException {@inheritDoc} 717bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException {@inheritDoc} 718bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws IllegalArgumentException {@inheritDoc} 719bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 720adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public int drainTo(Collection<? super E> c) { 721a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return drainTo(c, Integer.MAX_VALUE); 722adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 723adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 724bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 725bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws UnsupportedOperationException {@inheritDoc} 726bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws ClassCastException {@inheritDoc} 727bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException {@inheritDoc} 728bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws IllegalArgumentException {@inheritDoc} 729bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 730adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public int drainTo(Collection<? super E> c, int maxElements) { 731adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (c == null) 732adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project throw new NullPointerException(); 733adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (c == this) 734adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project throw new IllegalArgumentException(); 735adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (maxElements <= 0) 736adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return 0; 737adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 738adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 739adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 740a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int n = Math.min(size, maxElements); 741a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 0; i < n; i++) { 742a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson c.add((E) queue[0]); // In this order, in case add() throws. 743a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson dequeue(); 744adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 745adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return n; 746adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 747adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 748adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 749adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 750adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 751adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 752bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Atomically removes all of the elements from this queue. 753adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * The queue will be empty after this call returns. 754adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 755adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void clear() { 756adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 757adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 758adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 7598eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson Object[] array = queue; 7608eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size; 7618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson size = 0; 7628eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson for (int i = 0; i < n; i++) 7638eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson array[i] = null; 764adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 765adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 766adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 767adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 768adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 769bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 770b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Returns an array containing all of the elements in this queue. 771b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * The returned array elements are in no particular order. 772b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 773b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>The returned array will be "safe" in that no references to it are 774b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * maintained by this queue. (In other words, this method must allocate 775b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * a new array). The caller is thus free to modify the returned array. 776b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 777b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>This method acts as bridge between array-based and collection-based 778b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * APIs. 779b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 780b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @return an array containing all of the elements in this queue 781b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak */ 782b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public Object[] toArray() { 783b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak final ReentrantLock lock = this.lock; 784b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak lock.lock(); 785b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak try { 786b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return Arrays.copyOf(queue, size); 787b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } finally { 788b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak lock.unlock(); 789b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 790b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 791b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 792b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak /** 793bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Returns an array containing all of the elements in this queue; the 794bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * runtime type of the returned array is that of the specified array. 795bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * The returned array elements are in no particular order. 796bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * If the queue fits in the specified array, it is returned therein. 797bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Otherwise, a new array is allocated with the runtime type of the 798bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * specified array and the size of this queue. 799bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 800bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * <p>If this queue fits in the specified array with room to spare 801bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * (i.e., the array has more elements than this queue), the element in 802bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * the array immediately following the end of the queue is set to 8038eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code null}. 804bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 805bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * <p>Like the {@link #toArray()} method, this method acts as bridge between 806bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * array-based and collection-based APIs. Further, this method allows 807bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * precise control over the runtime type of the output array, and may, 808bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * under certain circumstances, be used to save allocation costs. 809bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 8108eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * <p>Suppose {@code x} is a queue known to contain only strings. 811bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * The following code can be used to dump the queue into a newly 8128eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * allocated array of {@code String}: 813bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 814b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <pre> {@code String[] y = x.toArray(new String[0]);}</pre> 815bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 8168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * Note that {@code toArray(new Object[0])} is identical in function to 8178eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * {@code toArray()}. 818bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * 819bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @param a the array into which the elements of the queue are to 820bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * be stored, if it is big enough; otherwise, a new array of the 821bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * same runtime type is allocated for this purpose 822bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @return an array containing all of the elements in this queue 823bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws ArrayStoreException if the runtime type of the specified array 824bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * is not a supertype of the runtime type of every element in 825bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * this queue 826bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @throws NullPointerException if the specified array is null 827bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 828adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public <T> T[] toArray(T[] a) { 829adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project final ReentrantLock lock = this.lock; 830adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 831adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 8328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson int n = size; 8338eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (a.length < n) 8348eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson // Make a new array of a's runtime type, but my contents: 8358eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return (T[]) Arrays.copyOf(queue, size, a.getClass()); 8368eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson System.arraycopy(queue, 0, a, 0, n); 8378eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson if (a.length > n) 8388eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson a[n] = null; 8398eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson return a; 840adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 841adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 842adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 843adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 844adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 845adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 846adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Returns an iterator over the elements in this queue. The 847adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * iterator does not return the elements in any particular order. 8488eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson * 849b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>The returned iterator is 850b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 851adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 852bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * @return an iterator over the elements in this queue 853adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 854adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public Iterator<E> iterator() { 855bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson return new Itr(toArray()); 856adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 857adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 858bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson /** 859bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson * Snapshot iterator that works off copy of underlying q array. 860bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson */ 8618eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson final class Itr implements Iterator<E> { 862bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson final Object[] array; // Array of all elements 863a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int cursor; // index of next element to return 864bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson int lastRet; // index of last element, or -1 if no such 865bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson 866bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson Itr(Object[] array) { 867bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson lastRet = -1; 868bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson this.array = array; 869adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 870adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 871adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public boolean hasNext() { 872bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson return cursor < array.length; 873adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 874adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 875adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public E next() { 876bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson if (cursor >= array.length) 877bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson throw new NoSuchElementException(); 878bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson lastRet = cursor; 879bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson return (E)array[cursor++]; 880adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 881adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 882adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void remove() { 883bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson if (lastRet < 0) 884bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson throw new IllegalStateException(); 8858eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson removeEQ(array[lastRet]); 886bba8d1acd6dfff06c94d761c67a30154ca5ca5dfJesse Wilson lastRet = -1; 887adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 888adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 889adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 890adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 89191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Saves this queue to a stream (that is, serializes it). 89291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 89391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * For compatibility with previous version of this class, elements 89491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * are first copied to a java.util.PriorityQueue, which is then 89591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * serialized. 896b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 897b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param s the stream 898b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws java.io.IOException if an I/O error occurs 899adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 900adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private void writeObject(java.io.ObjectOutputStream s) 901adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project throws java.io.IOException { 902adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.lock(); 903adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project try { 904a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // avoid zero capacity argument 905a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson q = new PriorityQueue<E>(Math.max(size, 1), comparator); 9068eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson q.addAll(this); 907adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project s.defaultWriteObject(); 908adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } finally { 9098eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson q = null; 910adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project lock.unlock(); 911adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 912adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 913adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 9148eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson /** 91591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Reconstitutes this queue from a stream (that is, deserializes it). 916b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param s the stream 917b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws ClassNotFoundException if the class of a serialized object 918b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * could not be found 919b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws java.io.IOException if an I/O error occurs 9208eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson */ 9218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson private void readObject(java.io.ObjectInputStream s) 9228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson throws java.io.IOException, ClassNotFoundException { 9238eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson try { 9248eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson s.defaultReadObject(); 9258eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson this.queue = new Object[q.size()]; 9268eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson comparator = q.comparator(); 9278eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson addAll(q); 9288eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } finally { 9298eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson q = null; 9308eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 9318eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 9328eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson 933b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak // Similar to Collections.ArraySnapshotSpliterator but avoids 934b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak // commitment to toArray until needed 935b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak static final class PBQSpliterator<E> implements Spliterator<E> { 936b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak final PriorityBlockingQueue<E> queue; 937b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak Object[] array; 938b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int index; 939b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int fence; 940b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 941b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak PBQSpliterator(PriorityBlockingQueue<E> queue, Object[] array, 942b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int index, int fence) { 943b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak this.queue = queue; 944b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak this.array = array; 945b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak this.index = index; 946b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak this.fence = fence; 947b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 948b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 949b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak final int getFence() { 950b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int hi; 951b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((hi = fence) < 0) 952b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak hi = fence = (array = queue.toArray()).length; 953b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return hi; 954b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 955b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 956b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public PBQSpliterator<E> trySplit() { 957b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 958b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return (lo >= mid) ? null : 959b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak new PBQSpliterator<E>(queue, array, lo, index = mid); 960b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 961b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 962b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak @SuppressWarnings("unchecked") 963b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public void forEachRemaining(Consumer<? super E> action) { 964b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak Object[] a; int i, hi; // hoist accesses and checks from loop 965b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (action == null) 966b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw new NullPointerException(); 967b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((a = array) == null) 968b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak fence = (a = queue.toArray()).length; 969b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((hi = fence) <= a.length && 970b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (i = index) >= 0 && i < (index = hi)) { 971b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak do { action.accept((E)a[i]); } while (++i < hi); 972b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 973b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 974b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 975b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public boolean tryAdvance(Consumer<? super E> action) { 976b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (action == null) 977b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw new NullPointerException(); 978b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (getFence() > index && index >= 0) { 979b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak @SuppressWarnings("unchecked") E e = (E) array[index++]; 980b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak action.accept(e); 981b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return true; 982b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 983b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return false; 984b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 985b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 986b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public long estimateSize() { return (long)(getFence() - index); } 987b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 988b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public int characteristics() { 989b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return Spliterator.NONNULL | Spliterator.SIZED | Spliterator.SUBSIZED; 990b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 991b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 992b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 993b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak /** 994b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Returns a {@link Spliterator} over the elements in this queue. 995b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 996b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>The returned spliterator is 997b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 998b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 999b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and 1000b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * {@link Spliterator#NONNULL}. 1001b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 1002b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @implNote 1003b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * The {@code Spliterator} additionally reports {@link Spliterator#SUBSIZED}. 1004b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 1005b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @return a {@code Spliterator} over the elements in this queue 1006b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @since 1.8 1007b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak */ 1008b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public Spliterator<E> spliterator() { 1009b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return new PBQSpliterator<E>(this, null, 0, -1); 1010b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 1011b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 10128eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson // Unsafe mechanics 1013b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe(); 1014b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak private static final long ALLOCATIONSPINLOCK; 1015a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static { 10168eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson try { 1017b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ALLOCATIONSPINLOCK = U.objectFieldOffset 1018b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (PriorityBlockingQueue.class.getDeclaredField("allocationSpinLock")); 1019b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } catch (ReflectiveOperationException e) { 1020a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new Error(e); 10218eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 10228eb35c835be1345d3873a82cc9e42f944d698afdJesse Wilson } 1023adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project} 1024