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* published by the Free Software Foundation. Oracle designates this
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/**
* Interfaces and classes providing a framework for locking and waiting
* for conditions that is distinct from built-in synchronization and
* monitors. The framework permits much greater flexibility in the use of
* locks and conditions, at the expense of more awkward syntax.
*
* <p>The {@link java.util.concurrent.locks.Lock} interface supports
* locking disciplines that differ in semantics (reentrant, fair, etc),
* and that can be used in non-block-structured contexts including
* hand-over-hand and lock reordering algorithms. The main implementation
* is {@link java.util.concurrent.locks.ReentrantLock}.
*
* <p>The {@link java.util.concurrent.locks.ReadWriteLock} interface
* similarly defines locks that may be shared among readers but are
* exclusive to writers. Only a single implementation, {@link
* java.util.concurrent.locks.ReentrantReadWriteLock}, is provided, since
* it covers most standard usage contexts. But programmers may create
* their own implementations to cover nonstandard requirements.
*
* <p>The {@link java.util.concurrent.locks.Condition} interface
* describes condition variables that may be associated with Locks.
* These are similar in usage to the implicit monitors accessed using
* {@code Object.wait}, but offer extended capabilities.
* In particular, multiple {@code Condition} objects may be associated
* with a single {@code Lock}. To avoid compatibility issues, the
* names of {@code Condition} methods are different from the
* corresponding {@code Object} versions.
*
* <p>The {@link java.util.concurrent.locks.AbstractQueuedSynchronizer}
* class serves as a useful superclass for defining locks and other
* synchronizers that rely on queuing blocked threads. The {@link
* java.util.concurrent.locks.AbstractQueuedLongSynchronizer} class
* provides the same functionality but extends support to 64 bits of
* synchronization state. Both extend class {@link
* java.util.concurrent.locks.AbstractOwnableSynchronizer}, a simple
* class that helps record the thread currently holding exclusive
* synchronization. The {@link java.util.concurrent.locks.LockSupport}
* class provides lower-level blocking and unblocking support that is
* useful for those developers implementing their own customized lock
* classes.
*
* @since 1.5
*/
package java.util.concurrent.locks;