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org.apache.oozie.util
Class MemoryLocks

java.lang.Object
  org.apache.oozie.util.MemoryLocks

public class MemoryLocks
extends Object

In memory resource locking that provides READ/WRITE lock capabilities.

Nested Class Summary

class

MemoryLocks.LockToken Lock token returned when obtaining a lock, the token must be released when the lock is not needed anymore.

Constructor Summary

MemoryLocks()

Method Summary

MemoryLocks.LockToken	getReadLock(String resource, long wait) Obtain a READ lock for a source.
MemoryLocks.LockToken	getWriteLock(String resource, long wait) Obtain a WRITE lock for a source.
int	size() Return the number of active locks.

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryLocks

public MemoryLocks()

Method Detail

size

public int size()

Return the number of active locks.

Returns:

the number of active locks.

getReadLock

public MemoryLocks.LockToken getReadLock(String resource,
                                         long wait)
                                  throws InterruptedException

Obtain a READ lock for a source.

Parameters:

resource - resource name.

wait - time out in milliseconds to wait for the lock, -1 means no timeout and 0 no wait.

Returns:

the lock token for the resource, or null if the lock could not be obtained.

Throws:

InterruptedException - thrown if the thread was interrupted while waiting.

getWriteLock

public MemoryLocks.LockToken getWriteLock(String resource,
                                          long wait)
                                   throws InterruptedException

Obtain a WRITE lock for a source.

Parameters:

resource - resource name.

wait - time out in milliseconds to wait for the lock, -1 means no timeout and 0 no wait.

Returns:

the lock token for the resource, or null if the lock could not be obtained.

Throws:

InterruptedException - thrown if the thread was interrupted while waiting.