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java.util.concurrent.locks
class ReentrantReadWriteLock.WriteLock

java.lang.Object extended by java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock
All Implemented Interfaces:
Serializable, Lock
Enclosing class:
ReentrantReadWriteLock

Most common way to construct:

ReentrantReadWriteLock rwl = …;

ReentrantReadWriteLock.WriteLock l = rwl.writeLock();

Based on 27 examples


public static class ReentrantReadWriteLock.WriteLock
extends Object
implements Lock, Serializable

The lock returned by method {@link ReentrantReadWriteLock#writeLock}.


Constructor Summary
protected

          Constructor for use by subclasses
 
Method Summary
 int

          Queries the number of holds on this write lock by the current thread.
 boolean

          Queries if this write lock is held by the current thread.
 void

          Acquires the write lock.
 void

          Acquires the write lock unless the current thread is java.lang.Thread.interrupt.
 Condition

          Returns a java.util.concurrent.locks.Condition instance for use with this java.util.concurrent.locks.Lock instance.
 String

          Returns a string identifying this lock, as well as its lock state.
 boolean

          Acquires the write lock only if it is not held by another thread at the time of invocation.
 boolean
tryLock(long timeout, TimeUnit unit)

          Acquires the write lock if it is not held by another thread within the given waiting time and the current thread has not been java.lang.Thread.interrupt.
 void

          Attempts to release this lock.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ReentrantReadWriteLock.WriteLock

protected ReentrantReadWriteLock.WriteLock(ReentrantReadWriteLock lock)
Constructor for use by subclasses

Parameters:
lock - the outer lock object
Method Detail

getHoldCount

public int getHoldCount()
Queries the number of holds on this write lock by the current thread. A thread has a hold on a lock for each lock action that is not matched by an unlock action. Identical in effect to {@link ReentrantReadWriteLock#getWriteHoldCount}.

Returns:
the number of holds on this lock by the current thread, or zero if this lock is not held by the current thread

isHeldByCurrentThread

public boolean isHeldByCurrentThread()
Queries if this write lock is held by the current thread. Identical in effect to {@link ReentrantReadWriteLock#isWriteLockedByCurrentThread}.

Returns:
{@code true} if the current thread holds this lock and {@code false} otherwise

lock

public void lock()
Acquires the write lock.

Acquires the write lock if neither the read nor write lock are held by another thread and returns immediately, setting the write lock hold count to one.

If the current thread already holds the write lock then the hold count is incremented by one and the method returns immediately.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until the write lock has been acquired, at which time the write lock hold count is set to one.


lockInterruptibly

public void lockInterruptibly()
                       throws InterruptedException
Acquires the write lock unless the current thread is {@linkplain Thread#interrupt interrupted}.

Acquires the write lock if neither the read nor write lock are held by another thread and returns immediately, setting the write lock hold count to one.

If the current thread already holds this lock then the hold count is incremented by one and the method returns immediately.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:

If the write lock is acquired by the current thread then the lock hold count is set to one.

If the current thread:

then {@link InterruptedException} is thrown and the current thread's interrupted status is cleared.

In this implementation, as this method is an explicit interruption point, preference is given to responding to the interrupt over normal or reentrant acquisition of the lock.

Throws:
InterruptedException - if the current thread is interrupted

newCondition

public Condition newCondition()
Returns a {@link Condition} instance for use with this {@link Lock} instance.

The returned {@link Condition} instance supports the same usages as do the {@link Object} monitor methods ({@link Object#wait() wait}, {@link Object#notify notify}, and {@link Object#notifyAll notifyAll}) when used with the built-in monitor lock.

Returns:
the Condition object

toString

public String toString()
Returns a string identifying this lock, as well as its lock state. The state, in brackets includes either the String {@code "Unlocked"} or the String {@code "Locked by"} followed by the {@linkplain Thread#getName name} of the owning thread.

Overrides:
toString in class Object
Returns:
a string identifying this lock, as well as its lock state

tryLock

public boolean tryLock()
Acquires the write lock only if it is not held by another thread at the time of invocation.

Acquires the write lock if neither the read nor write lock are held by another thread and returns immediately with the value {@code true}, setting the write lock hold count to one. Even when this lock has been set to use a fair ordering policy, a call to {@code tryLock()} will immediately acquire the lock if it is available, whether or not other threads are currently waiting for the write lock. This "barging" behavior can be useful in certain circumstances, even though it breaks fairness. If you want to honor the fairness setting for this lock, then use {@link #tryLock(long, TimeUnit) tryLock(0, TimeUnit.SECONDS) } which is almost equivalent (it also detects interruption).

If the current thread already holds this lock then the hold count is incremented by one and the method returns {@code true}.

If the lock is held by another thread then this method will return immediately with the value {@code false}.

Returns:
{@code true} if the lock was free and was acquired by the current thread, or the write lock was already held by the current thread; and {@code false} otherwise.

tryLock

public boolean tryLock(long timeout,
                       TimeUnit unit)
                throws InterruptedException
Acquires the write lock if it is not held by another thread within the given waiting time and the current thread has not been {@linkplain Thread#interrupt interrupted}.

Acquires the write lock if neither the read nor write lock are held by another thread and returns immediately with the value {@code true}, setting the write lock hold count to one. If this lock has been set to use a fair ordering policy then an available lock will not be acquired if any other threads are waiting for the write lock. This is in contrast to the {@link #tryLock()} method. If you want a timed {@code tryLock} that does permit barging on a fair lock then combine the timed and un-timed forms together:

if (lock.tryLock() || lock.tryLock(timeout, unit) ) { ... }
 

If the current thread already holds this lock then the hold count is incremented by one and the method returns {@code true}.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:

If the write lock is acquired then the value {@code true} is returned and the write lock hold count is set to one.

If the current thread:

then {@link InterruptedException} is thrown and the current thread's interrupted status is cleared.

If the specified waiting time elapses then the value {@code false} is returned. If the time is less than or equal to zero, the method will not wait at all.

In this implementation, as this method is an explicit interruption point, preference is given to responding to the interrupt over normal or reentrant acquisition of the lock, and over reporting the elapse of the waiting time.

Parameters:
timeout - the time to wait for the write lock
unit - the time unit of the timeout argument
Returns:
{@code true} if the lock was free and was acquired by the current thread, or the write lock was already held by the current thread; and {@code false} if the waiting time elapsed before the lock could be acquired.
Throws:
InterruptedException - if the current thread is interrupted

unlock

public void unlock()
Attempts to release this lock.

If the current thread is the holder of this lock then the hold count is decremented. If the hold count is now zero then the lock is released. If the current thread is not the holder of this lock then {@link IllegalMonitorStateException} is thrown.



This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.
This page displays the Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice:
Copyright 2008 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
The official Sun™ documentation can be found here at http://java.sun.com/javase/6/docs/api/.