com.gemstone.gemfire
Class CancelCriterion

java.lang.Object
  com.gemstone.gemfire.CancelCriterion

public abstract class CancelCriterion
extends Object

Abstract cancellation proxy for cancelling an operation, esp. a thread.

See Also:

ThreadInterruptedException

Constructor Summary

CancelCriterion()

Method Summary

abstract String	cancelInProgress() Indicate if the service is in the progress of being cancelled.
abstract String	cancelled() Indicates that the service has terminated.
void	checkCancelInProgress(Throwable e) See if the current operation is being cancelled.
void	checkCancelled() See if the current operation has been cancelled.
abstract RuntimeException	generateCancelledException(Throwable e) Template factory method for generating the exception to be thrown by checkCancelInProgress(Throwable).

Methods inherited from class java.lang.Object

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

Constructor Detail

CancelCriterion

public CancelCriterion()

Method Detail

cancelInProgress

public abstract String cancelInProgress()

Indicate if the service is in the progress of being cancelled. The typical use of this is to indicate, in the case of an InterruptedException, that the current operation should be cancelled.

In particular, a DistributionManager returns a non-null result if message distribution has been terminated.

Returns:

null if the service is not shutting down

cancelled

public abstract String cancelled()

Indicates that the service has terminated. The typical use of this is to poll within long loops to determine if the service has been terminated.

Returns:

a String to be used in an exception message, or null if it is not OK to cancel

checkCancelled

public final void checkCancelled()
                          throws ShutdownException

See if the current operation has been cancelled. If it has, throw a ShutdownException TODO: change to throws CancelledException instead

Throws:

ShutdownException - if we have been cancelled

See Also:

cancelled()

checkCancelInProgress

public final void checkCancelInProgress(Throwable e)
                                 throws ThreadInterruptedException

See if the current operation is being cancelled. If so, it either throws a ThreadInterruptedException or a ShutdownException. It throws the former only if the thread is currently in an interrupted state. TODO: change to throws CancelledException instead

Parameters:

e - an underlying exception, if any

Throws:

ThreadInterruptedException

ShutdownException

See Also:

cancelInProgress()

generateCancelledException

public abstract RuntimeException generateCancelledException(Throwable e)

Template factory method for generating the exception to be thrown by checkCancelInProgress(Throwable). Override this to specify different a exception for checkCancelInProgress to throw. TODO: change to return CancelledException instead

Parameters:

e - an underlying exception, if any

Returns:

RuntimeException to be thrown by checkCancelInProgress(), null if the receiver has not been cancelled.