com.adaptris.util

Class FifoMutexLock

java.lang.Object

com.adaptris.util.FifoMutexLock

public final class FifoMutexLock
extends java.lang.Object

Wraps an instance of Semaphore and adds 'mut-ex' behaviour.

The problem with Semaphore is that if you create a new instance with 1 permit (i.e. a mutex) then call release, the number of permits goes up to 2.

Constructor Summary

Constructors

Constructor and Description
FifoMutexLock() Creates a new instance.
FifoMutexLock(boolean b) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	acquire() Wraps call to Semaphore.acquire().
boolean	attempt(long ms) Wraps call to Semaphore.tryAcquire(long, TimeUnit).
boolean	permitAvailable() Returns true if the permit is currently avaialable.
void	release() Calls release on the underlying lock if a oermit is available to release, otherwise logs a message indicating that releases and acquires are not balanced.

Methods inherited from class java.lang.Object

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

Constructor Detail

FifoMutexLock

public FifoMutexLock()

Creates a new instance. Initialises underlying FIFOSemaphore with a single permit.

FifoMutexLock

public FifoMutexLock(boolean b)

Creates a new instance.

Parameters:

b - if true debug logging will be enabled

Method Detail

acquire

public void acquire()
             throws java.lang.InterruptedException

Wraps call to Semaphore.acquire().

Throws:

java.lang.InterruptedException - if the lock is interrupted.

See Also:

Semaphore

attempt

public boolean attempt(long ms)
                throws java.lang.InterruptedException

Wraps call to Semaphore.tryAcquire(long, TimeUnit).

Parameters:

ms - the amount of time in milliseconds

Returns:

true if the lock as successful.

Throws:

java.lang.InterruptedException - if the lock is interrupted.

See Also:

Semaphore

release

public void release()

Calls release on the underlying lock if a oermit is available to release, otherwise logs a message indicating that releases and acquires are not balanced.

permitAvailable

public boolean permitAvailable()

Returns true if the permit is currently avaialable.

Returns:

true if the permit is currently avaialable