org.apache.river.thread

Class RetryTask<V>

java.lang.Object

org.apache.river.thread.RetryTask<V>

Type Parameters:

V -

All Implemented Interfaces:

Runnable, java.util.concurrent.Future<V>, java.util.concurrent.RunnableFuture<V>, org.apache.river.constants.TimeConstants, FutureObserver.ObservableFuture<V>

public abstract class RetryTask<V>
extends Object
implements java.util.concurrent.RunnableFuture<V>, FutureObserver.ObservableFuture<V>, org.apache.river.constants.TimeConstants

Field Summary

Fields

Modifier and Type	Field and Description
protected static Logger	logger Logger for this class

Fields inherited from interface org.apache.river.constants.TimeConstants

DAYS, HOURS, MINUTES, SECONDS

Constructor Summary

Constructors

Constructor and Description
RetryTask(java.util.concurrent.ExecutorService executor, WakeupManager wakeupManager) Create a new RetryTask that will be scheduled with the given executor service, and which will perform retry scheduling using the given wakeup manager.
RetryTask(TaskManager manager, WakeupManager wakeupManager) Deprecated.

Method Summary

Modifier and Type	Method and Description
boolean	addObserver(FutureObserver<V> listener) Adds FutureObserver's to this ObservableFuture.
int	attempt() Return the attempt number, starting with zero.
boolean	cancel(boolean mayInterruptIfRunning) Cancel the retrying of the task.
V	get()
V	get(long time, java.util.concurrent.TimeUnit unit)
boolean	isCancelled() Return true if cancel has been invoked.
boolean	isDone() Return true if tryOnce has returned successfully.
long	retryTime() Return the next time at which we should make another attempt.
void	run() The run method used as a TaskManager.Task.
long	startTime() Return the time this task was created, or the last time reset was called.
abstract boolean	tryOnce() Make a single attempt.
boolean	waitFor(long duration)

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final Logger logger

Logger for this class

Constructor Detail

RetryTask

@Deprecated
public RetryTask(TaskManager manager,
                              WakeupManager wakeupManager)

Deprecated.

Create a new RetryTask that will be scheduled with the given task manager, and which will perform retry scheduling using the given wakeup manager.

RetryTask

public RetryTask(java.util.concurrent.ExecutorService executor,
                 WakeupManager wakeupManager)

Create a new RetryTask that will be scheduled with the given executor service, and which will perform retry scheduling using the given wakeup manager. TaskManager's Task.runAfter() is not called when using this constructor.

Parameters:

executor -

wakeupManager -

Method Detail

addObserver

public boolean addObserver(FutureObserver<V> listener)

Description copied from interface: FutureObserver.ObservableFuture

Adds FutureObserver's to this ObservableFuture.

Specified by:

addObserver in interface FutureObserver.ObservableFuture<V>

Parameters:

listener - to observe this.

Returns:

true if observer was added, false otherwise.

tryOnce

public abstract boolean tryOnce()

Make a single attempt. Return true if the attempt was successful. If the attempt is not successful, the task will be scheduled for a future retry.

run

public void run()

The run method used as a TaskManager.Task. This invokes tryOnce. If it is not successful, it schedules the task for a future retry at the time it gets by invoking retryTime.

Specified by:

run in interface Runnable

Specified by:

run in interface java.util.concurrent.RunnableFuture<V>

See Also:

tryOnce(), startTime

retryTime

public long retryTime()

Return the next time at which we should make another attempt. This is not an interval, but the actual time.

The implementation is free to do as it pleases with the policy here. The default implementation is to delay using intervals of 1 second, 5 seconds, 10 seconds, 1 minute, and 1 minute between attempts, and then retrying every five minutes forever.

The default implementation assumes it is being called from the default run method and that the current thread holds the lock on this object. If the caller does not own the lock the result is undefined and could result in an exception.

startTime

public long startTime()

Return the time this task was created, or the last time reset was called.

attempt

public int attempt()

Return the attempt number, starting with zero.

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Cancel the retrying of the task. This ensures that there will be no further attempts to invoke tryOnce. It will not interfere with any ongoing invocation of tryOnce unless a subclass overrides this to do so. Any override of this method should invoke super.cancel().

Specified by:

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

isCancelled

public boolean isCancelled()

Return true if cancel has been invoked.

Specified by:

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

isDone

public boolean isDone()

Return true if tryOnce has returned successfully.

Specified by:

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

waitFor

public boolean waitFor(long duration)
                throws InterruptedException

Throws:

InterruptedException

get

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

Specified by:

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

Throws:

InterruptedException

java.util.concurrent.ExecutionException

get

public V get(long time,
             java.util.concurrent.TimeUnit unit)
      throws InterruptedException,
             java.util.concurrent.ExecutionException,
             java.util.concurrent.TimeoutException

Specified by:

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

Throws:

InterruptedException

java.util.concurrent.ExecutionException

java.util.concurrent.TimeoutException