A scheduler of ( repeatable ) tasks that MUST be run sequentially.

This class can be used as a synchronization aid that assists a number of parties in running a task in a mutually exclusive fashion.

To run the task, a party invokes runOrSchedule. To permanently prevent the task from subsequent runs, the party invokes stop.

The parties can, but do not have to, operate in different threads.

The task can be either synchronous ( completes when its run method returns ), or asynchronous ( completed when its DeferredCompleter is explicitly completed ).

The next run of the task will not begin until the previous run has finished.

The task may invoke runOrSchedule itself, which may be a normal situation.

Nested and Inner Type Summary

Modifier and Type	Class and Description
public abstract static class	SequentialScheduler.CompleteRestartableTask A simple and self-contained task that completes once its `run` method returns.
public abstract static class	SequentialScheduler.DeferredCompleter An interface to signal the completion of a `RestartableTask`.
public static class	SequentialScheduler.LockingRestartableTask A task that runs its main loop within a block protected by a lock to provide memory visibility between runs.
public static interface	SequentialScheduler.RestartableTask A restartable task.
private class	SequentialScheduler.SchedulableTask An auxiliary task that starts the restartable task: `restartableTask.run(completer)`.
private class	SequentialScheduler.TryEndDeferredCompleter The only concrete `DeferredCompleter` implementation.

Field Summary

Modifier and Type	Field and Description
private static final int	AGAIN
private static final int	BEGIN
private final SequentialScheduler.DeferredCompleter	completer
private static final int	END
private static final int	OFFLOAD
private final SequentialScheduler.RestartableTask	restartableTask
private final SequentialScheduler.SchedulableTask	schedulableTask
private final AtomicInteger	state
private static final int	STOP

Constructor Summary

Access	Constructor and Description
public	SequentialScheduler(SequentialScheduler.RestartableTask restartableTask)

Method Summary

Modifier and Type	Method and Description
public boolean	isStopped() Tells whether, or not, this scheduler has been permanently stopped.
public static SequentialScheduler	Returns: a new `SequentialScheduler` that executes the provided `mainLoop` from within a `LockingRestartableTask`. lockingScheduler(Runnable The main loop of the new sequential scheduler mainLoop) Returns a new `SequentialScheduler` that executes the provided `mainLoop` from within a `LockingRestartableTask`.
public void	runOrSchedule() Runs or schedules the task to be run.
public void	runOrSchedule(Executor An executor in which to execute the task, if the task needs to be executed. executor) Executes or schedules the task to be executed in the provided executor.
private void	runOrSchedule(SequentialScheduler.SchedulableTask task, Executor executor)
public void	stop() Stops this scheduler.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

AGAIN	back to summary
private static final int AGAIN

BEGIN	back to summary
private static final int BEGIN

completer	back to summary
private final SequentialScheduler.DeferredCompleter completer

END	back to summary
private static final int END

OFFLOAD	back to summary
private static final int OFFLOAD

restartableTask	back to summary
private final SequentialScheduler.RestartableTask restartableTask

schedulableTask	back to summary
private final SequentialScheduler.SchedulableTask schedulableTask

state	back to summary
private final AtomicInteger state

STOP	back to summary
private static final int STOP

Constructor Detail

SequentialScheduler	back to summary
public SequentialScheduler(SequentialScheduler.RestartableTask restartableTask)

Method Detail

isStopped back to summary

isStopped	back to summary
public boolean isStopped() Tells whether, or not, this scheduler has been permanently stopped. Should be used from inside the task to poll the status of the scheduler, pretty much the same way as it is done for threads: `if (!Thread.currentThread().isInterrupted()) { ... }`

public boolean isStopped()

Tells whether, or not, this scheduler has been permanently stopped.

Should be used from inside the task to poll the status of the scheduler, pretty much the same way as it is done for threads:

if (!Thread.currentThread().isInterrupted()) {
        ...
    }

lockingScheduler back to summary

lockingScheduler	back to summary
public static SequentialScheduler lockingScheduler(Runnable mainLoop) Returns a new `SequentialScheduler` that executes the provided `mainLoop` from within a `LockingRestartableTask`. API Note This is equivalent to calling `new SequentialScheduler(new LockingRestartableTask(mainLoop))` The main loop must not perform any blocking operation. Parameters mainLoop:Runnable The main loop of the new sequential scheduler Returns:SequentialScheduler a new `SequentialScheduler` that executes the provided `mainLoop` from within a `LockingRestartableTask`.

public static SequentialScheduler lockingScheduler(Runnable mainLoop)

Returns a new SequentialScheduler that executes the provided mainLoop from within a LockingRestartableTask.

API Note

This is equivalent to calling new SequentialScheduler(new LockingRestartableTask(mainLoop)) The main loop must not perform any blocking operation.

Parameters

mainLoop:Runnable: The main loop of the new sequential scheduler

Returns:SequentialScheduler

a new SequentialScheduler that executes the provided mainLoop from within a LockingRestartableTask.

runOrSchedule	back to summary
public void runOrSchedule() Runs or schedules the task to be run. Implementation Specification The recursion which is possible here must be bounded: `this.runOrSchedule() completer.complete() this.runOrSchedule() ...` Implementation Note The recursion in this implementation has the maximum depth of 1.

runOrSchedule back to summary

runOrSchedule	back to summary
public void runOrSchedule(Executor executor) Executes or schedules the task to be executed in the provided executor. This method can be used when potential executing from a calling thread is not desirable. API Note The given executor can be `null` in which case calling `runOrSchedule(null)` is strictly equivalent to calling `runOrSchedule()`. Parameters executor:Executor An executor in which to execute the task, if the task needs to be executed.

public void runOrSchedule(Executor executor)

Executes or schedules the task to be executed in the provided executor.

This method can be used when potential executing from a calling thread is not desirable.

API Note

The given executor can be null in which case calling runOrSchedule(null) is strictly equivalent to calling runOrSchedule().

Parameters

executor:Executor: An executor in which to execute the task, if the task needs to be executed.

runOrSchedule	back to summary
private void runOrSchedule(SequentialScheduler.SchedulableTask task, Executor executor)

stop back to summary

stop	back to summary
public void stop() Stops this scheduler. Subsequent invocations of `runOrSchedule` are effectively no-ops. If the task has already begun, this invocation will not affect it, unless the task itself uses `isStopped()` method to check the state of the handler.

public void stop()

Stops this scheduler. Subsequent invocations of runOrSchedule are effectively no-ops.

If the task has already begun, this invocation will not affect it, unless the task itself uses isStopped() method to check the state of the handler.

jdk.internal.net.http.common back to summary

public abstract Class SequentialScheduler.CompleteRestartableTask

Class Inheritance

extends Object
implements RestartableTask

java.lang.Object
jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask

All Implemented Interfaces

jdk.internal.net.http.common.SequentialScheduler.RestartableTask

Known Direct Subclasses

jdk.internal.net.http.common.SequentialScheduler.LockingRestartableTask, jdk.internal.net.http.common.SSLFlowDelegate.Writer.WriterDownstreamPusher, jdk.internal.net.http.websocket.TransportImpl.SendTask, jdk.internal.net.http.websocket.TransportImpl.ReceiveTask, jdk.internal.net.http.websocket.WebSocketImpl.ReceiveTask, jdk.internal.net.http.BufferingSubscriber.DownstreamSubscription.PushDemandedTask, jdk.internal.net.http.PullPublisher.Subscription.PullTask

A simple and self-contained task that completes once its run method returns.

Constructor Summary

Access	Constructor and Description
public	CompleteRestartableTask()

Method Summary

Modifier and Type	Method and Description
public final void	run(SequentialScheduler.DeferredCompleter taskCompleter) Implements jdk.internal.net.http.common.SequentialScheduler.RestartableTask.run. The body of the task.
protected abstract void	run() The body of the task.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

CompleteRestartableTask	back to summary
public CompleteRestartableTask()

Method Detail

run	back to summary
public final void run(SequentialScheduler.DeferredCompleter taskCompleter) Implements jdk.internal.net.http.common.SequentialScheduler.RestartableTask.run. Doc from jdk.internal.net.http.common.SequentialScheduler.RestartableTask.run. The body of the task. Annotations @Override

run

back to summary

public final void run(SequentialScheduler.DeferredCompleter taskCompleter)

Implements jdk.internal.net.http.common.SequentialScheduler.RestartableTask.run.

Doc from jdk.internal.net.http.common.SequentialScheduler.RestartableTask.run.

The body of the task.

Annotations

@Override

run	back to summary
protected abstract void run() The body of the task.

jdk.internal.net.http.common back to summary

public abstract Class SequentialScheduler.DeferredCompleter

Class Inheritance

extends Object

java.lang.Object
jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter

Known Direct Subclasses

jdk.internal.net.http.common.SequentialScheduler.TryEndDeferredCompleter

An interface to signal the completion of a RestartableTask.

The invocation of complete completes the task. The invocation of complete may restart the task, if an attempt has previously been made to run the task while it was already running.

API Note

DeferredCompleter is useful when a task is not necessary complete when its run method returns, but will complete at a later time, and maybe in different thread. This type exists for readability purposes at use-sites only.

Constructor Summary

Access	Constructor and Description
private	DeferredCompleter() Extensible from this (outer) class ONLY.

Method Summary

Modifier and Type	Method and Description
public abstract void	complete() Completes the task.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

DeferredCompleter	back to summary
private DeferredCompleter() Extensible from this (outer) class ONLY.

Method Detail

complete	back to summary
public abstract void complete() Completes the task. Must be called once, and once only.

jdk.internal.net.http.common back to summary

public final Class SequentialScheduler.LockingRestartableTask

Class Inheritance

extends CompleteRestartableTask

java.lang.Object
jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask
jdk.internal.net.http.common.SequentialScheduler.LockingRestartableTask

A task that runs its main loop within a block protected by a lock to provide memory visibility between runs. Since the main loop can't run concurrently, the lock shouldn't be contended and no deadlock should ever be possible.

Field Summary

Modifier and Type	Field and Description
private final Lock	lock
private final Runnable	mainLoop

Constructor Summary

Access	Constructor and Description
public	LockingRestartableTask(Runnable mainLoop)

Method Summary

Modifier and Type	Method and Description
protected void	run() Implements abstract jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask.run. The body of the task.

Inherited from jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask:: run

Field Detail

lock	back to summary
private final Lock lock

mainLoop	back to summary
private final Runnable mainLoop

Constructor Detail

LockingRestartableTask	back to summary
public LockingRestartableTask(Runnable mainLoop)

Method Detail

run	back to summary
protected void run() Implements abstract jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask.run. Doc from jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask.run. The body of the task. Annotations @Override

run

back to summary

protected void run()

Implements abstract jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask.run.

Doc from jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask.run.

The body of the task.

Annotations

@Override

jdk.internal.net.http.common back to summary

public Interface SequentialScheduler.RestartableTask

Known Direct Implementers

jdk.internal.net.http.common.SequentialScheduler.CompleteRestartableTask, jdk.internal.net.http.SocketTube.SocketFlowTask

Annotations

@FunctionalInterface

A restartable task.

Method Summary

Modifier and Type	Method and Description
public void	run(SequentialScheduler.DeferredCompleter A completer that must be invoked once, and only once, when this task is logically finished taskCompleter) The body of the task.

Method Detail

run	back to summary
public void run(SequentialScheduler.DeferredCompleter taskCompleter) The body of the task. Parameters taskCompleter:SequentialScheduler.DeferredCompleter A completer that must be invoked once, and only once, when this task is logically finished

run

back to summary

public void run(SequentialScheduler.DeferredCompleter taskCompleter)

The body of the task.

Parameters

taskCompleter:SequentialScheduler.DeferredCompleter: A completer that must be invoked once, and only once, when this task is logically finished

jdk.internal.net.http.common back to summary

private final Class SequentialScheduler.SchedulableTask

Class Inheritance

extends Object
implements Runnable

java.lang.Object
jdk.internal.net.http.common.SequentialScheduler.SchedulableTask

All Implemented Interfaces

java.lang.Runnable

An auxiliary task that starts the restartable task: restartableTask.run(completer).

Constructor Summary

Access	Constructor and Description
private	SchedulableTask()

Method Summary

Modifier and Type	Method and Description
public void	run() Implements java.lang.Runnable.run. Runs this operation.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

SchedulableTask	back to summary
private SchedulableTask()

Method Detail

run	back to summary
public void run() Implements java.lang.Runnable.run. Doc from java.lang.Runnable.run. Runs this operation. Annotations @Override

run

back to summary

public void run()

Implements java.lang.Runnable.run.

Doc from java.lang.Runnable.run.

Runs this operation.

Annotations

@Override

jdk.internal.net.http.common back to summary

private Class SequentialScheduler.TryEndDeferredCompleter

Class Inheritance

extends DeferredCompleter

java.lang.Object
jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter
jdk.internal.net.http.common.SequentialScheduler.TryEndDeferredCompleter

The only concrete DeferredCompleter implementation.

Constructor Summary

Access	Constructor and Description
private	TryEndDeferredCompleter()

Method Summary

Modifier and Type	Method and Description
public void	complete() Implements abstract jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter.complete. Completes the task.

Constructor Detail

TryEndDeferredCompleter	back to summary
private TryEndDeferredCompleter()

Method Detail

complete	back to summary
public void complete() Implements abstract jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter.complete. Doc from jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter.complete. Completes the task. Must be called once, and once only. Annotations @Override

complete

back to summary

public void complete()

Implements abstract jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter.complete.

Doc from jdk.internal.net.http.common.SequentialScheduler.DeferredCompleter.complete.

Completes the task. Must be called once, and once only.

Annotations

@Override