2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
26 * This file is available under and governed by the GNU General Public
27 * License version 2 only, as published by the Free Software Foundation.
28 * However, the following notice accompanied the original version of this
31 * Written by Doug Lea with assistance from members of JCP JSR-166
32 * Expert Group and released to the public domain, as explained at
33 * http://creativecommons.org/publicdomain/zero/1.0/
37 * Interfaces and classes providing a framework for locking and waiting
38 * for conditions that is distinct from built-in synchronization and
39 * monitors. The framework permits much greater flexibility in the use of
40 * locks and conditions, at the expense of more awkward syntax.
42 * <p>The {@link java.util.concurrent.locks.Lock} interface supports
43 * locking disciplines that differ in semantics (reentrant, fair, etc),
44 * and that can be used in non-block-structured contexts including
45 * hand-over-hand and lock reordering algorithms. The main implementation
46 * is {@link java.util.concurrent.locks.ReentrantLock}.
48 * <p>The {@link java.util.concurrent.locks.ReadWriteLock} interface
49 * similarly defines locks that may be shared among readers but are
50 * exclusive to writers. Only a single implementation, {@link
51 * java.util.concurrent.locks.ReentrantReadWriteLock}, is provided, since
52 * it covers most standard usage contexts. But programmers may create
53 * their own implementations to cover nonstandard requirements.
55 * <p>The {@link java.util.concurrent.locks.Condition} interface
56 * describes condition variables that may be associated with Locks.
57 * These are similar in usage to the implicit monitors accessed using
58 * {@code Object.wait}, but offer extended capabilities.
59 * In particular, multiple {@code Condition} objects may be associated
60 * with a single {@code Lock}. To avoid compatibility issues, the
61 * names of {@code Condition} methods are different from the
62 * corresponding {@code Object} versions.
64 * <p>The {@link java.util.concurrent.locks.AbstractQueuedSynchronizer}
65 * class serves as a useful superclass for defining locks and other
66 * synchronizers that rely on queuing blocked threads. The {@link
67 * java.util.concurrent.locks.AbstractQueuedLongSynchronizer} class
68 * provides the same functionality but extends support to 64 bits of
69 * synchronization state. Both extend class {@link
70 * java.util.concurrent.locks.AbstractOwnableSynchronizer}, a simple
71 * class that helps record the thread currently holding exclusive
72 * synchronization. The {@link java.util.concurrent.locks.LockSupport}
73 * class provides lower-level blocking and unblocking support that is
74 * useful for those developers implementing their own customized lock
79 package java.util.concurrent.locks;