org.openbites.concurrent.locks.gcs

Class GcsLock

java.lang.Object

org.openbites.concurrent.locks.gcs.GcsLock

All Implemented Interfaces:

Serializable, Lock, DistributedLock

public class GcsLock
extends Object
implements DistributedLock, Serializable

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
GcsLock(GcsLockConfig lockConfig)

Method Summary

Modifier and Type	Method and Description
void	addLockListener(GcsLockListener listener) Add a lock listener as the callback for state change
boolean	isHeldByCurrentThread()
boolean	isLocked()
void	lock() Acquires the lock.
void	lockInterruptibly() Acquires the lock unless the current thread is interrupted.
void	removeLockListener(GcsLockListener listener) Remove a lock listener as the callback for state change
boolean	tryLock() Acquires the lock only if it is free at the time of invocation.
boolean	tryLock(long time, TimeUnit timeUnit) Acquires the lock if it is free within the given waiting time and the current thread has not been interrupted.
void	unlock() Releases the lock.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.openbites.concurrent.locks.DistributedLock

newCondition

Constructor Detail

GcsLock

public GcsLock(GcsLockConfig lockConfig)

Method Detail

tryLock

public boolean tryLock()

Acquires the lock only if it is free at the time of invocation.

Acquires the lock if it is available and returns immediately with the value true. If the lock is not available then this method will return immediately with the value false.

Any exception would be returned as the parameter in the callback GcsLockListener#acquireLockException(java.lang.Exception)

Specified by:

tryLock in interface Lock

Returns:

true if the lock was acquired and false otherwise

tryLock

public boolean tryLock(long time,
                       TimeUnit timeUnit)
                throws InterruptedException

Acquires the lock if it is free within the given waiting time and the current thread has not been interrupted.

If the lock is available this method returns immediately with the value true. If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:

• The lock is acquired by the current thread; or
• Some other thread interrupts the current thread, and interruption of lock acquisition is supported; or
• The specified waiting time elapses

If the lock is acquired then the value true is returned.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while acquiring the lock, and interruption of lock acquisition is supported,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

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

Specified by:

tryLock in interface Lock

Parameters:

time - the maximum time to wait for the lock

timeUnit - the time unit of the time argument

Returns:

true if the lock was acquired and false if the waiting time elapsed before the lock was acquired

Throws:

InterruptedException - if the current thread is interrupted while acquiring the lock (and interruption of lock acquisition is supported)

lock

public void lock()

Acquires the lock.

If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until the lock has been acquired.

Any exception would be returned as the parameter in the callback GcsLockListener#acquireLockException(java.lang.Exception)

Specified by:

lock in interface Lock

lockInterruptibly

public void lockInterruptibly()
                       throws InterruptedException

Acquires the lock unless the current thread is interrupted.

Acquires the lock if it is available and returns immediately.

If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:

• The lock is acquired by the current thread; or
• Some other thread interrupts the current thread, and interruption of lock acquisition is supported.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while acquiring the lock, and interruption of lock acquisition is supported,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

Specified by:

lockInterruptibly in interface Lock

Throws:

InterruptedException - if the current thread is interrupted while acquiring the lock (and interruption of lock acquisition is supported)

unlock

public void unlock()

Releases the lock.

While used in multi-thread environment only the thread that originally acquired the lock is able to release the lock.

Any exception would be returned as the parameter in the callback GcsLockListener#releaseLockException(java.lang.Exception)

Specified by:

unlock in interface Lock

isLocked

public boolean isLocked()

Returns:

true if the lock has been acquired and false otherwise

isHeldByCurrentThread

public boolean isHeldByCurrentThread()

Returns:

true if the lock was acquired by the current thread false otherwise

addLockListener

public void addLockListener(GcsLockListener listener)

Add a lock listener as the callback for state change

Parameters:

listener -

removeLockListener

public void removeLockListener(GcsLockListener listener)

Remove a lock listener as the callback for state change

Parameters:

listener -