net.sourceforge.domian.util.concurrent.locks
Class SemaphoreSynchronizer

java.lang.Object
  net.sourceforge.domian.util.concurrent.locks.SemaphoreSynchronizer

All Implemented Interfaces:

Synchronizer

public final class SemaphoreSynchronizer
extends java.lang.Object
implements Synchronizer

A Synchronizer implementation using two Semaphore instances.

Since:

0.4

Author:

Eirik Torske

Nested Class Summary

Nested classes/interfaces inherited from interface net.sourceforge.domian.util.concurrent.locks.Synchronizer

Synchronizer.MODE

Field Summary

private java.util.concurrent.Semaphore	concurrentAccessSemaphore Semaphore managing permits and blocking queue for concurrent-mode blocks.
private java.util.concurrent.Semaphore	exclusiveAccessSemaphore Semaphore managing one single permit and blocking queue for exclusive-mode blocks.
private static boolean	FAIR
private static java.util.concurrent.atomic.AtomicBoolean	hasAcquiredExecutionPermitAtomicBoolean
private static java.lang.ThreadLocal<java.lang.Boolean>	hasAcquiredExecutionPermitThreadLocal Permits must only be acquired once per thread.
private static org.slf4j.Logger	log
private static int	MAX_NUMBER_OF_CONCURRENT_PERMITS
private static boolean	NON_FAIR

Constructor Summary

SemaphoreSynchronizer()

Method Summary

<T,C extends java.util.concurrent.Callable<T>> T	callConcurrently(C callable) Calls a Callable in a concurrent manner.
<T,C extends java.util.concurrent.Callable<T>> T	callExclusively(C callable) Calls a Callable in an exclusive manner.
<R extends java.lang.Runnable> void	runConcurrently(R runnable) Runs a Runnable in a concurrent manner.
<R extends java.lang.Runnable> void	runExclusively(R runnable) Runs a Runnable in an exclusive manner.
private static void	setThisThreadHasAcquiredExecutionPermitTo(java.lang.Boolean booleanValue)
private static java.lang.Boolean	thisThreadHasAlreadyAcquiredExecutionPermit()

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final org.slf4j.Logger log

MAX_NUMBER_OF_CONCURRENT_PERMITS

private static final int MAX_NUMBER_OF_CONCURRENT_PERMITS

See Also:

Constant Field Values

FAIR

private static final boolean FAIR

NON_FAIR

private static final boolean NON_FAIR

concurrentAccessSemaphore

private final java.util.concurrent.Semaphore concurrentAccessSemaphore

Semaphore managing permits and blocking queue for concurrent-mode blocks.

exclusiveAccessSemaphore

private final java.util.concurrent.Semaphore exclusiveAccessSemaphore

Semaphore managing one single permit and blocking queue for exclusive-mode blocks.

hasAcquiredExecutionPermitAtomicBoolean

private static final java.util.concurrent.atomic.AtomicBoolean hasAcquiredExecutionPermitAtomicBoolean

hasAcquiredExecutionPermitThreadLocal

private static final java.lang.ThreadLocal<java.lang.Boolean> hasAcquiredExecutionPermitThreadLocal

Permits must only be acquired once per thread. This is needed to prevent deadlock for nested invocations.

Constructor Detail

SemaphoreSynchronizer

public SemaphoreSynchronizer()

Method Detail

thisThreadHasAlreadyAcquiredExecutionPermit

private static java.lang.Boolean thisThreadHasAlreadyAcquiredExecutionPermit()

setThisThreadHasAcquiredExecutionPermitTo

private static void setThisThreadHasAcquiredExecutionPermitTo(java.lang.Boolean booleanValue)

runConcurrently

public <R extends java.lang.Runnable> void runConcurrently(R runnable)

Description copied from interface: Synchronizer

Runs a Runnable in a concurrent manner.

Specified by:

runConcurrently in interface Synchronizer

Parameters:

runnable - the runnable to invoke concurrently, managed by this class

callConcurrently

public <T,C extends java.util.concurrent.Callable<T>> T callConcurrently(C callable)

Description copied from interface: Synchronizer

Calls a Callable in a concurrent manner.

Specified by:

callConcurrently in interface Synchronizer

Parameters:

callable - the callable to invoke concurrently, managed by this class

Returns:

the Callable's return value, or null if no return value

runExclusively

public <R extends java.lang.Runnable> void runExclusively(R runnable)

Description copied from interface: Synchronizer

Runs a Runnable in an exclusive manner. Firstly, it will wait for all other exclusive Runnables and Callables to finish, if any. Then it will wait for already running concurrent Runnables and Callables to finish, if any. Finally it will run, queuing up all other Runnables and Callables managed by the same Synchronizer instance. When done, all queues are released.

Specified by:

runExclusively in interface Synchronizer

Parameters:

runnable - the runnable to invoke exclusively, managed by this class

callExclusively

public <T,C extends java.util.concurrent.Callable<T>> T callExclusively(C callable)

Description copied from interface: Synchronizer

Calls a Callable in an exclusive manner. Firstly, it will wait for all other exclusive Runnables and Callables to finish, if any. Then it will wait for already running concurrent Runnables and Callables to finish, if any. Finally it will run, queuing up all other Runnables and Callables managed by the same Synchronizer instance. When done, all queues are released.

Specified by:

callExclusively in interface Synchronizer

Parameters:

callable - the callable to invoke exclusively, managed by this class

Returns:

the Callable's return value, or null if no return value