Module aeonics.core

Package aeonics.manager

Class Executor.Task<T>

java.lang.Object

aeonics.manager.Executor.Task<T>

Type Parameters:

T - the return type of the task

Enclosing class:

Executor

public static final class Executor.Task<T>
extends java.lang.Object

This class represents a task that is running, is done or will run in the future. It is a simplified wrapper around CompletableFuture designed to be used by the Executor implementations.

Method Summary

Modifier and Type	Method	Description
protected static Executor.Task<java.lang.Void>	all(java.util.List<Executor.Task<?>> tasks, java.util.concurrent.Executor executor)	Returns a new task that completes when all tasks are completed (successfully or not).
Executor.Task<java.lang.Void>	anyway(Functions.BiConsumer<T,java.lang.Throwable> task)	Schedules another task to run upon completion of this task regardless of the successful or failure.
<U> Executor.Task<U>	anyway(Functions.BiFunction<T,java.lang.Throwable,? extends U> task)	Schedules another task to run upon completion of this task regardless of the successful or failure.
Executor.Task<java.lang.Void>	anyway(Functions.Runnable task)	Schedules another task to run upon completion of this task regardless of the successful or failure.
<U> Executor.Task<U>	anyway(Functions.Supplier<? extends U> task)	Schedules another task to run upon completion of this task regardless of the successful or failure.
protected static <U> Executor.Task<U>	async(Functions.Supplier<U> task, java.util.concurrent.Executor executor)	Schedules the given task to run in the specified executor.
T	await()	Waits for the result of this task to be available and returns the value.
void	cancel()	Cancels this task if it is not done yet.
protected static <T> Executor.Task<T>	completed(T value, java.util.concurrent.Executor executor)	Returns an already completed task.
protected static Executor.Task<java.lang.Void>	failed(java.lang.Throwable value, java.util.concurrent.Executor executor)	Returns an already failed task.
<U> Executor.Task<U>	link(Executor.Task<U> task)	Link the completion of the current task to that of the specified one.
<U> Executor.Task<U>	link(Functions.Function<T,Executor.Task<U>> task)	Link the completion of the current task to that of the specified one.
Executor.Task<T>	or(Functions.Consumer<java.lang.Throwable> task)	Schedules another task to run if this task threw an exception.
Executor.Task<T>	or(Functions.Function<java.lang.Throwable,? extends T> task)	Schedules another task to run if this task threw an exception.
Executor.Task<T>	or(Functions.Runnable task)	Schedules another task to run if this task threw an exception.
Executor.Task<T>	or(Functions.Supplier<? extends T> task)	Schedules another task to run if this task threw an exception.
protected static <U> Executor.Task<U>	sync(Functions.Supplier<U> task, java.util.concurrent.Executor executor)	Schedules the given task to run in the specified executor.
Executor.Task<java.lang.Void>	then(Functions.Consumer<? super T> task)	Schedules another task to run upon successful completion of this task
<U> Executor.Task<U>	then(Functions.Function<? super T,? extends U> task)	Schedules another task to run upon successful completion of this task
Executor.Task<java.lang.Void>	then(Functions.Runnable task)	Schedules another task to run upon successful completion of this task
<U> Executor.Task<U>	then(Functions.Supplier<? extends U> task)	Schedules another task to run upon successful completion of this task

Methods inherited from class java.lang.Object

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

Method Detail

completed

protected static <T> Executor.Task<T> completed(T value,
                                                java.util.concurrent.Executor executor)

Returns an already completed task.

Type Parameters:

T - the return type

Parameters:

value - the completion value

executor - the executor in which subsequent tasks should run

Returns:

an already completed task

failed

protected static Executor.Task<java.lang.Void> failed(java.lang.Throwable value,
                                                      java.util.concurrent.Executor executor)

Returns an already failed task.

Parameters:

value - the failure cause

executor - the executor in which subsequent tasks should run

Returns:

an already failed task

sync

protected static <U> Executor.Task<U> sync(Functions.Supplier<U> task,
                                           java.util.concurrent.Executor executor)

Schedules the given task to run in the specified executor. Any then(aeonics.util.Functions.Runnable), or(aeonics.util.Functions.Runnable) (or variants) methods will run synchronously in the same thread as the task.

Type Parameters:

U - the return type of the task

Parameters:

task - the task to run

executor - the executor in which the task should run

Returns:

the task object to eventually chain or cancel operations

async

protected static <U> Executor.Task<U> async(Functions.Supplier<U> task,
                                            java.util.concurrent.Executor executor)

Schedules the given task to run in the specified executor. Any then(aeonics.util.Functions.Runnable), or(aeonics.util.Functions.Runnable) (or variants) methods will be rescheduled asynchronously in the same executor as the task.

Type Parameters:

U - the return type of the task

Parameters:

task - the task to run

executor - the executor in which the task should run

Returns:

the task object to eventually chain or cancel operations

then

public Executor.Task<java.lang.Void> then(Functions.Runnable task)

Schedules another task to run upon successful completion of this task

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

then

public Executor.Task<java.lang.Void> then(Functions.Consumer<? super T> task)

Schedules another task to run upon successful completion of this task

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

then

public <U> Executor.Task<U> then(Functions.Supplier<? extends U> task)

Schedules another task to run upon successful completion of this task

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

then

public <U> Executor.Task<U> then(Functions.Function<? super T,? extends U> task)

Schedules another task to run upon successful completion of this task

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

or

public Executor.Task<T> or(Functions.Runnable task)

Schedules another task to run if this task threw an exception. This stage completes with a null result. If you wish to interrupt processing, then simply rethrow the exception.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

or

public Executor.Task<T> or(Functions.Consumer<java.lang.Throwable> task)

Schedules another task to run if this task threw an exception. This stage completes with a null result. If you wish to interrupt processing, then simply rethrow the exception.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

or

public Executor.Task<T> or(Functions.Supplier<? extends T> task)

Schedules another task to run if this task threw an exception. This stage completes with the returned value. If you wish to interrupt processing, then simply rethrow the exception.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

or

public Executor.Task<T> or(Functions.Function<java.lang.Throwable,? extends T> task)

Schedules another task to run if this task threw an exception. This stage completes with the returned value. If you wish to interrupt processing, then simply rethrow the exception.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

anyway

public Executor.Task<java.lang.Void> anyway(Functions.Runnable task)

Schedules another task to run upon completion of this task regardless of the successful or failure.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

anyway

public Executor.Task<java.lang.Void> anyway(Functions.BiConsumer<T,java.lang.Throwable> task)

Schedules another task to run upon completion of this task regardless of the successful or failure.

If the second parameter (the exception) is null, it indicates a successful operation and the first parameter (the return value) is filled. That value may be null too.

If the second parameter (the exception) is not null, it indicates a failed operation and the first parameter (the return value) is null.

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

anyway

public <U> Executor.Task<U> anyway(Functions.Supplier<? extends U> task)

Schedules another task to run upon completion of this task regardless of the successful or failure.

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

anyway

public <U> Executor.Task<U> anyway(Functions.BiFunction<T,java.lang.Throwable,? extends U> task)

Schedules another task to run upon completion of this task regardless of the successful or failure.

If the second parameter (the exception) is null, it indicates a successful operation and the first parameter (the return value) is filled. That value may be null too.

If the second parameter (the exception) is not null, it indicates a failed operation and the first parameter (the return value) is null.

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

link

public <U> Executor.Task<U> link(Executor.Task<U> task)

Link the completion of the current task to that of the specified one.

The linked task will only execute in case of successful completion of this one.

If this task completes successfully and the linked task too, then the result is the linked task's value. This operation is non-blocking and the returned task will be pending until then.

Beware that this operation may cause a dead lock in case linking a task that is enqueued and has no chance to execute.

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

link

public <U> Executor.Task<U> link(Functions.Function<T,Executor.Task<U>> task)

Link the completion of the current task to that of the specified one.

The linked task will only execute in case of successful completion of this one.

If this task completes successfully and the linked task too, then the result is the linked task's value. This operation is non-blocking and the returned task will be pending until then.

Beware that this operation may cause a dead lock in case linking a task that is enqueued and has no chance to execute.

Type Parameters:

U - the task return type

Parameters:

task - the other task

Returns:

a new task object to eventually chain or cancel operations

await

public T await()

Waits for the result of this task to be available and returns the value. Beware that this operation may cause a dead lock in case awaiting a task that is enqueued and has no chance to execute.

It is generally bad practice to use this method unless you know exactly what you are doing.

Returns:

the output value of the task

Throws:

java.util.concurrent.CompletionException - if the task itself threw an exception

java.util.concurrent.CancellationException - if the task was cancelled using cancel()

all

protected static Executor.Task<java.lang.Void> all(java.util.List<Executor.Task<?>> tasks,
                                                   java.util.concurrent.Executor executor)

Returns a new task that completes when all tasks are completed (successfully or not). If you are interested by the result of individual tasks, you should inspect each of them after the returned task completes. Beware that this operation may cause a dead lock in case providing a task that is enqueued and has no chance to execute.

Parameters:

tasks - the list of tasks to group together

executor - the executor in which subsequent tasks should run

Returns:

a new task that completes when all tasks are completed

cancel

public void cancel()

Cancels this task if it is not done yet. This method applies to this task only and not the parent tasks.