Package com.oracle.coherence.concurrent.executor

Class AbstractTaskCoordinator<T>

java.lang.Object

com.oracle.coherence.concurrent.executor.AbstractTaskCoordinator<T>

Type Parameters:

T - the type of the Task

All Implemented Interfaces:

Task.Coordinator<T>

Direct Known Subclasses:

ClusteredTaskCoordinator

public abstract class AbstractTaskCoordinator<T>
extends Object
implements Task.Coordinator<T>

A base implementation of a Task.Coordinator.

Since:

21.12

Author:

bo

Field Summary

Fields

Modifier and Type	Field	Description
protected AtomicBoolean	f_cancelled	Has the Task been cancelled.
protected AtomicBoolean	f_closed	Is the Task.Coordinator closed to accept more subscribers or offers of items.
protected ExecutorService	f_executorService	The ExecutorService from the TaskExecutorService for asynchronously publishing items.
protected boolean	f_fRetainTask	The flag to indicate whether the Task is retained.
protected String	f_sTaskId	The unique identity of the Task.
protected Result<T>	m_lastValue	The last value offered (that we'll offer to new Task.Subscribers).
protected Set<Task.Subscriber<? super T>>	m_setSubscribers	The Task.Subscribers to which items will be published.

Constructor Summary

Constructors

Constructor	Description
AbstractTaskCoordinator(String taskId, ExecutorService executorService, boolean fRetainTask)	Construct an AbstractTaskCoordinator.

Method Summary

Modifier and Type	Method	Description
boolean	cancel(boolean mayInterruptIfRunning)	Attempts to cancel execution of the Task.
void	close()	Closes the AbstractTaskCoordinator and notifies the Task.Subscribers that there will no longer be any further items by calling Task.Subscriber.onComplete().
protected void	closeSubscriber(Task.Subscriber<? super T> subscriber, boolean fRemove)	A helper method to close a Task.Subscriber using the calling Thread.
String	getTaskId()	Obtains the unique identity of the Task being coordinated.
boolean	hasSubscribers()	Determine if the AbstractTaskCoordinator currently has any Task.Subscribers.
boolean	isCancelled()	Returns true if the Task was cancelled before it completed normally.
boolean	isDone()	Returns true if the Task completed.
void	offer(Result<T> item)	Offers an item to be asynchronously published to current Task.Subscribers.
void	subscribe(Task.Subscriber<? super T> subscriber)	Subscribes the specified Task.Subscriber to the Task.Coordinator of a Task to receive collected results.
protected abstract void	subscribeRetainedTask(Task.Subscriber<?> subscriber)	Subscribes to a retained task (a task that has completed execution, but it still held in memory).

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.oracle.coherence.concurrent.executor.Task.Coordinator

getProperties

Field Detail

f_executorService

protected final ExecutorService f_executorService

The ExecutorService from the TaskExecutorService for asynchronously publishing items.

f_sTaskId

protected final String f_sTaskId

The unique identity of the Task.

f_fRetainTask

protected final boolean f_fRetainTask

The flag to indicate whether the Task is retained.

f_closed

protected final AtomicBoolean f_closed

Is the Task.Coordinator closed to accept more subscribers or offers of items.

f_cancelled

protected final AtomicBoolean f_cancelled

Has the Task been cancelled.

m_setSubscribers

protected Set<Task.Subscriber<? super T>> m_setSubscribers

The Task.Subscribers to which items will be published.

m_lastValue

protected volatile Result<T> m_lastValue

The last value offered (that we'll offer to new Task.Subscribers).

Constructor Detail

AbstractTaskCoordinator

public AbstractTaskCoordinator(String taskId,
                               ExecutorService executorService,
                               boolean fRetainTask)

Construct an AbstractTaskCoordinator.

Parameters:

taskId - Task ID

executorService - ExecutorService to use for async notifications to Task.Coordinators

fRetainTask - whether to retain the Task after completion

Method Detail

getTaskId

public String getTaskId()

Description copied from interface: Task.Coordinator

Obtains the unique identity of the Task being coordinated.

Specified by:

getTaskId in interface Task.Coordinator<T>

Returns:

the task identity

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Description copied from interface: Task.Coordinator

Attempts to cancel execution of the Task. This attempt will fail if the task has already completed, has already been cancelled, or could not be cancelled for some other reason. If successful, and this task has not started when cancel is called, this task should never run. If the task has already started, then the mayInterruptIfRunning parameter determines whether the thread executing this task should be interrupted in an attempt to stop the task.

After this method returns, subsequent calls to isDone() will always return true. Subsequent calls to isDone() will always return true if this method returned true.

Specified by:

cancel in interface Task.Coordinator<T>

Parameters:

mayInterruptIfRunning - true if the thread executing this task should be interrupted; otherwise, in-progress tasks are allowed to complete

Returns:

false if the task could not be cancelled, typically because it has already completed normally; true otherwise

See Also:

Future.cancel(boolean)

isCancelled

public boolean isCancelled()

Description copied from interface: Task.Coordinator

Returns true if the Task was cancelled before it completed normally.

Specified by:

isCancelled in interface Task.Coordinator<T>

Returns:

true if this task was cancelled before it completed

See Also:

Future.isCancelled()

isDone

public boolean isDone()

Description copied from interface: Task.Coordinator

Returns true if the Task completed. Completion may be due to normal termination, an exception, or cancellation -- in all of these cases, this method will return true.

Specified by:

isDone in interface Task.Coordinator<T>

Returns:

true if this task completed

See Also:

Future.isDone()

subscribe

public void subscribe(Task.Subscriber<? super T> subscriber)

Description copied from interface: Task.Coordinator

Subscribes the specified Task.Subscriber to the Task.Coordinator of a Task to receive collected results.

If already subscribed, or the attempt to subscribe fails, the Task.Subscriber.onError(Throwable) method is invoked with an IllegalStateException.

Specified by:

subscribe in interface Task.Coordinator<T>

Parameters:

subscriber - the Task.Subscriber

closeSubscriber

protected void closeSubscriber(Task.Subscriber<? super T> subscriber,
                               boolean fRemove)

A helper method to close a Task.Subscriber using the calling Thread.

Closing a Task.Subscriber involves calling either Task.Subscriber.onComplete() or Task.Subscriber.onError(Throwable) when an error occurred.

Parameters:

subscriber - the Task.Subscriber

fRemove - true if the Task.Subscriber should additionally be removed from the Task.Coordinator,false otherwise

close

public void close()

Closes the AbstractTaskCoordinator and notifies the Task.Subscribers that there will no longer be any further items by calling Task.Subscriber.onComplete().

hasSubscribers

public boolean hasSubscribers()

Determine if the AbstractTaskCoordinator currently has any Task.Subscribers.

Returns:

true if the AbstractTaskCoordinator has Task.Subscribers, false otherwise

offer

public void offer(Result<T> item)

Offers an item to be asynchronously published to current Task.Subscribers.

Parameters:

item - the item

subscribeRetainedTask

protected abstract void subscribeRetainedTask(Task.Subscriber<?> subscriber)

Subscribes to a retained task (a task that has completed execution, but it still held in memory).

Parameters:

subscriber - the subscriber

Throws:

IllegalStateException - if there is no task to subscribe to