net.spy.memcached.internal

Class OperationFuture<T>

java.lang.Object

net.spy.memcached.compat.SpyObject

net.spy.memcached.internal.AbstractListenableFuture<T,OperationCompletionListener>

net.spy.memcached.internal.OperationFuture<T>

Type Parameters:

T - Type of object returned from this future.

All Implemented Interfaces:

java.util.concurrent.Future<T>, ListenableFuture<T,OperationCompletionListener>

public class OperationFuture<T>
extends AbstractListenableFuture<T,OperationCompletionListener>
implements java.util.concurrent.Future<T>

Managed future for operations.

From an OperationFuture, application code can determine if the status of a given Operation in an asynchronous manner.

If for example we needed to update the keys "user::name", "user::friendlist" because later in the method we were going to verify the change occurred as expected interacting with the user, we can fire multiple IO operations simultaneously with this concept.

Field Summary

Fields

Modifier and Type	Field and Description
protected OperationStatus	status

Constructor Summary

Constructors

Constructor and Description
OperationFuture(java.lang.String k, java.util.concurrent.CountDownLatch l, java.util.concurrent.atomic.AtomicReference<T> oref, long opTimeout, java.util.concurrent.ExecutorService service) Create an OperationFuture for a given async operation.
OperationFuture(java.lang.String k, java.util.concurrent.CountDownLatch l, long opTimeout, java.util.concurrent.ExecutorService service) Create an OperationFuture for a given async operation.

Method Summary

Modifier and Type	Method and Description
OperationFuture<T>	addListener(OperationCompletionListener listener) Add a listener to the future, which will be executed once the operation completes.
boolean	cancel() Cancel this operation, if possible.
boolean	cancel(boolean ign) Deprecated.
T	get() Get the results of the given operation.
T	get(long duration, java.util.concurrent.TimeUnit units) Get the results of the given operation.
java.lang.Long	getCas() Get the CAS for this operation.
java.lang.String	getKey() Get the key for this operation.
OperationStatus	getStatus() Get the current status of this operation.
boolean	isCancelled() Whether or not the Operation associated with this OperationFuture has been canceled.
boolean	isDone() Whether or not the Operation is done and result can be retrieved with get().
OperationFuture<T>	removeListener(OperationCompletionListener listener) Remove a previously added listener from the future.
void	set(T o, OperationStatus s) Set the Operation associated with this OperationFuture.
void	setCas(long inCas) Set the key for this operation.
void	setOperation(Operation to) Set the Operation associated with this OperationFuture.
void	signalComplete() Signals that this future is complete.

Methods inherited from class net.spy.memcached.internal.AbstractListenableFuture

addToListeners, executor, notifyListener, notifyListeners, notifyListeners, removeFromListeners

Methods inherited from class net.spy.memcached.compat.SpyObject

getLogger

Methods inherited from class java.lang.Object

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

Field Detail

status

protected OperationStatus status

Constructor Detail

OperationFuture

public OperationFuture(java.lang.String k,
                       java.util.concurrent.CountDownLatch l,
                       long opTimeout,
                       java.util.concurrent.ExecutorService service)

Create an OperationFuture for a given async operation. This is intended for internal use only.

Parameters:

k - the key for the operation

l - the latch to be used counting down the OperationFuture

opTimeout - the timeout within which the operation needs to be done

OperationFuture

public OperationFuture(java.lang.String k,
                       java.util.concurrent.CountDownLatch l,
                       java.util.concurrent.atomic.AtomicReference<T> oref,
                       long opTimeout,
                       java.util.concurrent.ExecutorService service)

Create an OperationFuture for a given async operation. This is intended for internal use only.

Parameters:

k - the key for the operation

l - the latch to be used counting down the OperationFuture

oref - an AtomicReference associated with the operation

opTimeout - the timeout within which the operation needs to be done

Method Detail

cancel

public boolean cancel(boolean ign)

Deprecated.

Cancel this operation, if possible.

Specified by:

cancel in interface java.util.concurrent.Future<T>

Parameters:

ign - not used

Returns:

true if the operation has not yet been written to the network

cancel

public boolean cancel()

Cancel this operation, if possible.

Returns:

true if the operation has not yet been written to the network

get

public T get()
      throws java.lang.InterruptedException,
             java.util.concurrent.ExecutionException

Get the results of the given operation. As with the Future interface, this call will block until the results of the future operation has been received.

Specified by:

get in interface java.util.concurrent.Future<T>

Returns:

the operation results of this OperationFuture

Throws:

java.lang.InterruptedException

java.util.concurrent.ExecutionException

get

public T get(long duration,
             java.util.concurrent.TimeUnit units)
      throws java.lang.InterruptedException,
             java.util.concurrent.TimeoutException,
             java.util.concurrent.ExecutionException

Get the results of the given operation. As with the Future interface, this call will block until the results of the future operation has been received.

Specified by:

get in interface java.util.concurrent.Future<T>

Parameters:

duration - amount of time to wait

units - unit of time to wait

Returns:

the operation results of this OperationFuture

Throws:

java.lang.InterruptedException

java.util.concurrent.TimeoutException

java.util.concurrent.ExecutionException

getKey

public java.lang.String getKey()

Get the key for this operation.

Returns:

the key for this operation

setCas

public void setCas(long inCas)

Set the key for this operation.

Parameters:

inCas - the CAS value

getCas

public java.lang.Long getCas()

Get the CAS for this operation. The interrupted status of the current thread is cleared by this method. Inspect the returned OperationStatus to check whether an interruption has taken place.

Returns:

the CAS for this operation or null if unsuccessful.

Throws:

java.lang.UnsupportedOperationException - If this is for an ASCII protocol configured client.

getStatus

public OperationStatus getStatus()

Get the current status of this operation. Note that the operation status may change as the operation is tried and potentially retried against the servers specified by the NodeLocator. The interrupted status of the current thread is cleared by this method. Inspect the returned OperationStatus to check whether an interruption has taken place.

Returns:

OperationStatus

set

public void set(T o,
                OperationStatus s)

Set the Operation associated with this OperationFuture. This is intended for internal use only.

Parameters:

o - the Operation object itself

s - the OperationStatus associated with this operation

setOperation

public void setOperation(Operation to)

Set the Operation associated with this OperationFuture. This is intended for internal use only.

Parameters:

to - the Operation to set this OperationFuture to be tracking

isCancelled

public boolean isCancelled()

Whether or not the Operation associated with this OperationFuture has been canceled. One scenario in which this can occur is if the connection is lost and the Operation has been sent over the network. In this case, the operation may or may not have reached the server before the connection was dropped.

Specified by:

isCancelled in interface java.util.concurrent.Future<T>

Returns:

true if the Operation has been canceled

isDone

public boolean isDone()

Whether or not the Operation is done and result can be retrieved with get(). The most common way to wait for this OperationFuture is to use the get() method which will block. This method allows one to check if it's complete without blocking.

Specified by:

isDone in interface java.util.concurrent.Future<T>

Returns:

true if the Operation is done

addListener

public OperationFuture<T> addListener(OperationCompletionListener listener)

Description copied from interface: ListenableFuture

Add a listener to the future, which will be executed once the operation completes.

Specified by:

addListener in interface ListenableFuture<T,OperationCompletionListener>

Parameters:

listener - the listener which will be executed.

Returns:

the current future to allow for object-chaining.

removeListener

public OperationFuture<T> removeListener(OperationCompletionListener listener)

Description copied from interface: ListenableFuture

Remove a previously added listener from the future.

Specified by:

removeListener in interface ListenableFuture<T,OperationCompletionListener>

Parameters:

listener - the previously added listener.

Returns:

the current future to allow for object-chaining.

signalComplete

public void signalComplete()

Signals that this future is complete.