local.tomas.util.sync
Class Semaphore

java.lang.Object
  local.tomas.util.sync.Semaphore

All Implemented Interfaces:

SyncInterface

public class Semaphore
extends Object
implements SyncInterface

A Semaphore is a kind of synchronized counter. It can be used to limit access to a resource to a specific number of clients.

Version:

1.0

Author:

Tomas Teubner

Constructor Summary

Semaphore(int count)
Construct semaphore.

Method Summary

void	lock() Lock 1 resource.
void	lock(int n) Lock n resources.
boolean	trylock() Try to lock 1 resource.
boolean	trylock(int n) Try to lock n resources.
void	unlock() Unlock 1 resource.
void	unlock(int n) Unlock n resources

Methods inherited from class java.lang.Object

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

Constructor Detail

Semaphore

public Semaphore(int count)

Construct semaphore.

Parameters:

count - number of resources controlled by this semaphore

Method Detail

trylock

public boolean trylock(int n)

Try to lock n resources. If the number of available resources is less than n, false is returned.

Parameters:

n - number of resources

Returns:

true if lock succeeded, false otherwise

trylock

public boolean trylock()

Try to lock 1 resource.

Specified by:

trylock in interface SyncInterface

Returns:

true if lock succeeded, false otherwise

lock

public void lock(int n)
          throws InterruptedException

Lock n resources. If the number of available resources is less than n, the call to this method will block until they become available.

Parameters:

n - number of resources

Throws:

InterruptedException

lock

public void lock()
          throws InterruptedException

Lock 1 resource.

Specified by:

lock in interface SyncInterface

Throws:

InterruptedException

unlock

public void unlock(int n)

Unlock n resources

Parameters:

n - number of resources

unlock

public void unlock()

Unlock 1 resource.

Specified by:

unlock in interface SyncInterface