ca.odell.glazedlists.util.concurrent
Class J2SE14ReadWriteLock.WriteLock

java.lang.Object
  ca.odell.glazedlists.util.concurrent.J2SE14ReadWriteLock.WriteLock

All Implemented Interfaces:

Lock, Serializable

Enclosing class:

J2SE14ReadWriteLock

public static class J2SE14ReadWriteLock.WriteLock
extends Object
implements Lock, Serializable

The lock returned by method J2SE14ReadWriteLock.writeLock().

See Also:

Serialized Form

Constructor Summary

protected

J2SE14ReadWriteLock.WriteLock(J2SE14ReadWriteLock lock) Constructor for use by subclasses

Method Summary

int	getHoldCount() Queries the number of holds on this write lock by the current thread.
boolean	isHeldByCurrentThread() Queries if this write lock is held by the current thread.
void	lock() Acquires the write lock.
void	lockInterruptibly() Acquires the write lock unless the current thread is interrupted.
String	toString() Returns a string identifying this lock, as well as its lock state.
boolean	tryLock() Acquires the write lock only if it is not held by another thread at the time of invocation.
void	unlock() Attempts to release this lock.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

J2SE14ReadWriteLock.WriteLock

protected J2SE14ReadWriteLock.WriteLock(J2SE14ReadWriteLock lock)

Constructor for use by subclasses

Parameters:

lock - the outer lock object

Throws:

NullPointerException - if the lock is null

Method Detail

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.

Specified by:

lock in interface Lock

lockInterruptibly

public void lockInterruptibly()
                       throws InterruptedException

Acquires the write lock unless the current thread is 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:

• The write lock is acquired by the current thread; or
• Some other thread interrupts the current thread.

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

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while acquiring the write lock,

then 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

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

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

Specified by:

tryLock in interface Lock

Returns:

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 false otherwise.

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 IllegalMonitorStateException is thrown.

Specified by:

unlock in interface Lock

Throws:

IllegalMonitorStateException - if the current thread does not hold this lock.

toString

public String toString()

Returns a string identifying this lock, as well as its lock state. The state, in brackets includes either the String "Unlocked" or the String "Locked by" followed by the name of the owning thread.

Overrides:

toString in class Object

Returns:

a string identifying this lock, as well as its lock state

isHeldByCurrentThread

public boolean isHeldByCurrentThread()

Queries if this write lock is held by the current thread. Identical in effect to ReentrantReadWriteLock.

Returns:

true if the current thread holds this lock and false otherwise

Since:

1.6

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 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

Since:

1.6