com.tangosol.net.cache
Class ReadWriteBackingMap.ReadLatch

java.lang.Object
  com.tangosol.net.cache.ReadWriteBackingMap.ReadLatch

Enclosing class:

ReadWriteBackingMap

protected class ReadWriteBackingMap.ReadLatch
extends Object

A synchronization construct used to coordinate asynchronous loads by the refresh-ahead thread with cache accesses by other threads.

The refresh-ahead thread places a new ReadLatch in the control map before performing a load operation on the cache store. The presence of the latch signals to a thread executing the ReadWriteBackingMap.get(java.lang.Object) method that an asynchronous load is in progress. This thread can then wait on the latch to get the results of the asynchronous load. This thread is then responsible for removing the latch from the control map.

Additionally, a thread performing a ReadWriteBackingMap.put(java.lang.Object, java.lang.Object) or ReadWriteBackingMap.remove(java.lang.Object) operation can cancel an ongoing asynchronous load using the latch. This thread is also responsible for removing the latch from the control map.

Author:

jh 2005.02.11

Constructor Summary

protected

ReadWriteBackingMap.ReadLatch(Object oKey) Create a new ReadLatch for the specified key.

Method Summary

void	cancel() Cancel the load operation.
void	cancel(Throwable t) Cancel the load operation due to an exception.
void	complete(Object oValue) Complete the load operation.
Object	getKey() Return the key that is being loaded by the refresh-ahead thread.
Object	getValue() Return the result of the load operation.
boolean	isCanceled() Return true if the load operation has been canceled.
boolean	isComplete() Return true if the load operation is complete.

Constructor Detail

ReadWriteBackingMap.ReadLatch

protected ReadWriteBackingMap.ReadLatch(Object oKey)

Create a new ReadLatch for the specified key.

Parameters:

oKey - the key that is being loaded by the refresh-ahead thread

Method Detail

cancel

public void cancel()

Cancel the load operation. This method has no effect if the operation has already been completed or canceled.

cancel

public void cancel(Throwable t)

Cancel the load operation due to an exception. This method has no effect if the operation has already been completed or canceled.

complete

public void complete(Object oValue)

Complete the load operation. The specified value and entry is the result of the load operation. This method has no effect if the operation has already been completed or canceled.

Parameters:

oValue - the result of the load operation

isComplete

public boolean isComplete()

Return true if the load operation is complete. The results of the load operation can be retrieved using the getValue() method.

Returns:

true if the load operation is complete

isCanceled

public boolean isCanceled()

Return true if the load operation has been canceled.

Returns:

true if the load operation has been canceled

getKey

public Object getKey()

Return the key that is being loaded by the refresh-ahead thread.

Returns:

the key that is being loaded

getValue

public Object getValue()

Return the result of the load operation.

Note: this method should not be called by the refresh-ahead deamon thread

Returns:

the result of the load operation