Class CompletableFuture<T>

java.lang.Object

java.util.concurrent.CompletableFuture<T>

All Implemented Interfaces:

CompletionStage<T>, Future<T>

public class CompletableFuture<T>
extends Object
implements Future<T>, CompletionStage<T>

java.util.concurrent.CompletableFuture for the Codename One runtime.

A stage completes on the thread that completed the one before it, as in the JDK. The ...Async methods without an executor run on a pool of daemon threads -- there is no fork-join pool here -- and never on the UI thread; a continuation that touches the user interface passes an executor that calls Display.callSerially, or calls it itself.

The class is safe to use from several threads at once: its state is kept in atomics, and every dependent action runs exactly once.

get() and join() on the UI thread wait through JdkHost.blockUi, which on a device is Display.invokeAndBlock: events keep being dispatched.

Exceptions travel as in the JDK: a stage that depends on a failed one fails with a CompletionException whose cause is the original; get() reports that cause in an ExecutionException, join() throws the CompletionException, and both throw CancellationException after cancel.

Not provided: obtrudeValue, obtrudeException, getNumberOfDependents, delayedExecutor and state().

Constructor Summary

Constructors

Constructor	Description
CompletableFuture()

Method Summary

Modifier and Type	Method	Description
CompletableFuture<Void>	acceptEither(CompletionStage<? extends T> other, Consumer<? super T> action)
CompletableFuture<Void>	acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action)
CompletableFuture<Void>	acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action, Executor executor)
static CompletableFuture<Void>	allOf(CompletableFuture<?>... given)
static CompletableFuture<Object>	anyOf(CompletableFuture<?>... futures)
<U> CompletableFuture<U>	applyToEither(CompletionStage<? extends T> other, Function<? super T, U> fn)
<U> CompletableFuture<U>	applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T, U> fn)
<U> CompletableFuture<U>	applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T, U> fn, Executor executor)
boolean	cancel(boolean mayInterruptIfRunning)	Stops the work if it has not started.
boolean	complete(T value)
CompletableFuture<T>	completeAsync(Supplier<? extends T> supplier)
CompletableFuture<T>	completeAsync(Supplier<? extends T> supplier, Executor executor)
static <U> CompletableFuture<U>	completedFuture(U value)
static <U> CompletionStage<U>	completedStage(U value)
boolean	completeExceptionally(Throwable ex)
CompletableFuture<T>	completeOnTimeout(T value, long timeout, TimeUnit unit)
CompletableFuture<T>	copy()	A new future that completes as this one does.
Executor	defaultExecutor()	The executor the ...Async methods use when given none.
CompletableFuture<T>	exceptionally(Function<Throwable, ? extends T> fn)
CompletableFuture<T>	exceptionallyAsync(Function<Throwable, ? extends T> fn)
CompletableFuture<T>	exceptionallyAsync(Function<Throwable, ? extends T> fn, Executor executor)
CompletableFuture<T>	exceptionallyCompose(Function<Throwable, ? extends CompletionStage<T>> fn)
Throwable	exceptionNow()	The exception of a future that failed.
static <U> CompletableFuture<U>	failedFuture(Throwable ex)
static <U> CompletionStage<U>	failedStage(Throwable ex)
T	get()	Waits for the work to finish and returns its result.
T	get(long timeout, TimeUnit unit)	Waits up to timeout for the work to finish and returns its result.
T	getNow(T valueIfAbsent)
<U> CompletableFuture<U>	handle(BiFunction<? super T, Throwable, ? extends U> fn)
<U> CompletableFuture<U>	handleAsync(BiFunction<? super T, Throwable, ? extends U> fn)
<U> CompletableFuture<U>	handleAsync(BiFunction<? super T, Throwable, ? extends U> fn, Executor executor)
boolean	isCancelled()	Whether Future.cancel(boolean) cancelled the work before it ran.
boolean	isCompletedExceptionally()
boolean	isDone()	Whether the work has finished: completed, failed or cancelled.
T	join()	The result, waiting for it; a failure is a CompletionException.
CompletionStage<T>	minimalCompletionStage()	A stage that completes as this one does, and that completing does not complete this one: a copy().
<U> CompletableFuture<U>	newIncompleteFuture()
CompletableFuture<T>	orTimeout(long timeout, TimeUnit unit)	Fails this future with a TimeoutException if it is not complete when the time has passed.
T	resultNow()	The result of a future that completed normally.
CompletableFuture<Void>	runAfterBoth(CompletionStage<?> other, Runnable action)
CompletableFuture<Void>	runAfterBothAsync(CompletionStage<?> other, Runnable action)
CompletableFuture<Void>	runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)
CompletableFuture<Void>	runAfterEither(CompletionStage<?> other, Runnable action)
CompletableFuture<Void>	runAfterEitherAsync(CompletionStage<?> other, Runnable action)
CompletableFuture<Void>	runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)
static CompletableFuture<Void>	runAsync(Runnable runnable)
static CompletableFuture<Void>	runAsync(Runnable runnable, Executor executor)
static <U> CompletableFuture<U>	supplyAsync(Supplier<U> supplier)
static <U> CompletableFuture<U>	supplyAsync(Supplier<U> supplier, Executor executor)
CompletableFuture<Void>	thenAccept(Consumer<? super T> action)
CompletableFuture<Void>	thenAcceptAsync(Consumer<? super T> action)
CompletableFuture<Void>	thenAcceptAsync(Consumer<? super T> action, Executor executor)
<U> CompletableFuture<Void>	thenAcceptBoth(CompletionStage<? extends U> other, BiConsumer<? super T, ? super U> action)
<U> CompletableFuture<Void>	thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T, ? super U> action)
<U> CompletableFuture<Void>	thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T, ? super U> action, Executor executor)
<U> CompletableFuture<U>	thenApply(Function<? super T, ? extends U> fn)
<U> CompletableFuture<U>	thenApplyAsync(Function<? super T, ? extends U> fn)
<U> CompletableFuture<U>	thenApplyAsync(Function<? super T, ? extends U> fn, Executor executor)
<U,V> CompletableFuture<V>	thenCombine(CompletionStage<? extends U> other, BiFunction<? super T, ? super U, ? extends V> fn)
<U,V> CompletableFuture<V>	thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T, ? super U, ? extends V> fn)
<U,V> CompletableFuture<V>	thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T, ? super U, ? extends V> fn, Executor executor)
<U> CompletableFuture<U>	thenCompose(Function<? super T, ? extends CompletionStage<U>> fn)
<U> CompletableFuture<U>	thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn)
<U> CompletableFuture<U>	thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn, Executor executor)
CompletableFuture<Void>	thenRun(Runnable action)
CompletableFuture<Void>	thenRunAsync(Runnable action)
CompletableFuture<Void>	thenRunAsync(Runnable action, Executor executor)
CompletableFuture<T>	toCompletableFuture()
String	toString()	Returns a string representation of the object.
CompletableFuture<T>	whenComplete(BiConsumer<? super T, ? super Throwable> action)
CompletableFuture<T>	whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action)
CompletableFuture<T>	whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action, Executor executor)

Methods inherited from class Object

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

Constructor Details

CompletableFuture

public CompletableFuture()

Method Details

complete

public boolean complete(T value)

completeExceptionally

public boolean completeExceptionally(Throwable ex)

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Description copied from interface: Future

Stops the work if it has not started. Answers whether it was cancelled; whether work already running is interrupted is up to the implementation and to mayInterruptIfRunning.

Specified by:

cancel in interface Future<T>

Parameters:

mayInterruptIfRunning - whether a running task may be interrupted

Returns:

true when this call cancelled it

isCancelled

public boolean isCancelled()

Description copied from interface: Future

Whether Future.cancel(boolean) cancelled the work before it ran.

Specified by:

isCancelled in interface Future<T>

Returns:

true when cancelled

isDone

public boolean isDone()

Description copied from interface: Future

Whether the work has finished: completed, failed or cancelled.

Specified by:

isDone in interface Future<T>

Returns:

true once it will not change again

isCompletedExceptionally

public boolean isCompletedExceptionally()

get

public T get()
      throws InterruptedException,
ExecutionException

Description copied from interface: Future

Waits for the work to finish and returns its result.

Specified by:

get in interface Future<T>

Returns:

the result

Throws:

InterruptedException - when the waiting thread is interrupted

ExecutionException - when the work threw; Throwable.getCause() is what it threw

get

public T get(long timeout,
 TimeUnit unit)
      throws InterruptedException,
ExecutionException,
TimeoutException

Description copied from interface: Future

Waits up to timeout for the work to finish and returns its result.

Specified by:

get in interface Future<T>

Parameters:

timeout - how long to wait, in unit

unit - the unit of timeout

Returns:

the result

Throws:

InterruptedException - when the waiting thread is interrupted

ExecutionException - when the work threw

TimeoutException - when it has not finished in time

join

public T join()

The result, waiting for it; a failure is a CompletionException.

getNow

public T getNow(T valueIfAbsent)

resultNow

public T resultNow()

The result of a future that completed normally.

exceptionNow

public Throwable exceptionNow()

The exception of a future that failed.

defaultExecutor

public Executor defaultExecutor()

The executor the ...Async methods use when given none.

newIncompleteFuture

public <U> CompletableFuture<U> newIncompleteFuture()

completedFuture

public static <U> CompletableFuture<U> completedFuture(U value)

failedFuture

public static <U> CompletableFuture<U> failedFuture(Throwable ex)

completedStage

public static <U> CompletionStage<U> completedStage(U value)

failedStage

public static <U> CompletionStage<U> failedStage(Throwable ex)

supplyAsync

public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)

supplyAsync

public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier,
 Executor executor)

runAsync

public static CompletableFuture<Void> runAsync(Runnable runnable)

runAsync

public static CompletableFuture<Void> runAsync(Runnable runnable,
 Executor executor)

completeAsync

public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier)

completeAsync

public CompletableFuture<T> completeAsync(Supplier<? extends T> supplier,
 Executor executor)

allOf

public static CompletableFuture<Void> allOf(CompletableFuture<?>... given)

anyOf

public static CompletableFuture<Object> anyOf(CompletableFuture<?>... futures)

orTimeout

public CompletableFuture<T> orTimeout(long timeout,
 TimeUnit unit)

Fails this future with a TimeoutException if it is not complete when the time has passed.

completeOnTimeout

public CompletableFuture<T> completeOnTimeout(T value,
 long timeout,
 TimeUnit unit)

thenApply

public <U> CompletableFuture<U> thenApply(Function<? super T, ? extends U> fn)

Specified by:

thenApply in interface CompletionStage<T>

thenApplyAsync

public <U> CompletableFuture<U> thenApplyAsync(Function<? super T, ? extends U> fn)

Specified by:

thenApplyAsync in interface CompletionStage<T>

thenApplyAsync

public <U> CompletableFuture<U> thenApplyAsync(Function<? super T, ? extends U> fn,
 Executor executor)

Specified by:

thenApplyAsync in interface CompletionStage<T>

thenAccept

public CompletableFuture<Void> thenAccept(Consumer<? super T> action)

Specified by:

thenAccept in interface CompletionStage<T>

thenAcceptAsync

public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action)

Specified by:

thenAcceptAsync in interface CompletionStage<T>

thenAcceptAsync

public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action,
 Executor executor)

Specified by:

thenAcceptAsync in interface CompletionStage<T>

thenRun

public CompletableFuture<Void> thenRun(Runnable action)

Specified by:

thenRun in interface CompletionStage<T>

thenRunAsync

public CompletableFuture<Void> thenRunAsync(Runnable action)

Specified by:

thenRunAsync in interface CompletionStage<T>

thenRunAsync

public CompletableFuture<Void> thenRunAsync(Runnable action,
 Executor executor)

Specified by:

thenRunAsync in interface CompletionStage<T>

thenCompose

public <U> CompletableFuture<U> thenCompose(Function<? super T, ? extends CompletionStage<U>> fn)

Specified by:

thenCompose in interface CompletionStage<T>

thenComposeAsync

public <U> CompletableFuture<U> thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn)

Specified by:

thenComposeAsync in interface CompletionStage<T>

thenComposeAsync

public <U> CompletableFuture<U> thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn,
 Executor executor)

Specified by:

thenComposeAsync in interface CompletionStage<T>

handle

public <U> CompletableFuture<U> handle(BiFunction<? super T, Throwable, ? extends U> fn)

Specified by:

handle in interface CompletionStage<T>

handleAsync

public <U> CompletableFuture<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn)

Specified by:

handleAsync in interface CompletionStage<T>

handleAsync

public <U> CompletableFuture<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn,
 Executor executor)

Specified by:

handleAsync in interface CompletionStage<T>

whenComplete

public CompletableFuture<T> whenComplete(BiConsumer<? super T, ? super Throwable> action)

Specified by:

whenComplete in interface CompletionStage<T>

whenCompleteAsync

public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action)

Specified by:

whenCompleteAsync in interface CompletionStage<T>

whenCompleteAsync

public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action,
 Executor executor)

Specified by:

whenCompleteAsync in interface CompletionStage<T>

exceptionally

public CompletableFuture<T> exceptionally(Function<Throwable, ? extends T> fn)

Specified by:

exceptionally in interface CompletionStage<T>

exceptionallyAsync

public CompletableFuture<T> exceptionallyAsync(Function<Throwable, ? extends T> fn)

exceptionallyAsync

public CompletableFuture<T> exceptionallyAsync(Function<Throwable, ? extends T> fn,
 Executor executor)

exceptionallyCompose

public CompletableFuture<T> exceptionallyCompose(Function<Throwable, ? extends CompletionStage<T>> fn)

thenCombine

public <U,V> CompletableFuture<V> thenCombine(CompletionStage<? extends U> other,
 BiFunction<? super T, ? super U, ? extends V> fn)

Specified by:

thenCombine in interface CompletionStage<T>

thenCombineAsync

public <U,V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T, ? super U, ? extends V> fn)

Specified by:

thenCombineAsync in interface CompletionStage<T>

thenCombineAsync

public <U,V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T, ? super U, ? extends V> fn,
 Executor executor)

Specified by:

thenCombineAsync in interface CompletionStage<T>

thenAcceptBoth

public <U> CompletableFuture<Void> thenAcceptBoth(CompletionStage<? extends U> other,
 BiConsumer<? super T, ? super U> action)

Specified by:

thenAcceptBoth in interface CompletionStage<T>

thenAcceptBothAsync

public <U> CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
 BiConsumer<? super T, ? super U> action)

Specified by:

thenAcceptBothAsync in interface CompletionStage<T>

thenAcceptBothAsync

public <U> CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
 BiConsumer<? super T, ? super U> action,
 Executor executor)

Specified by:

thenAcceptBothAsync in interface CompletionStage<T>

runAfterBoth

public CompletableFuture<Void> runAfterBoth(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterBoth in interface CompletionStage<T>

runAfterBothAsync

public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterBothAsync in interface CompletionStage<T>

runAfterBothAsync

public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other,
 Runnable action,
 Executor executor)

Specified by:

runAfterBothAsync in interface CompletionStage<T>

applyToEither

public <U> CompletableFuture<U> applyToEither(CompletionStage<? extends T> other,
 Function<? super T, U> fn)

Specified by:

applyToEither in interface CompletionStage<T>

applyToEitherAsync

public <U> CompletableFuture<U> applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T, U> fn)

Specified by:

applyToEitherAsync in interface CompletionStage<T>

applyToEitherAsync

public <U> CompletableFuture<U> applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T, U> fn,
 Executor executor)

Specified by:

applyToEitherAsync in interface CompletionStage<T>

acceptEither

public CompletableFuture<Void> acceptEither(CompletionStage<? extends T> other,
 Consumer<? super T> action)

Specified by:

acceptEither in interface CompletionStage<T>

acceptEitherAsync

public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other,
 Consumer<? super T> action)

Specified by:

acceptEitherAsync in interface CompletionStage<T>

acceptEitherAsync

public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other,
 Consumer<? super T> action,
 Executor executor)

Specified by:

acceptEitherAsync in interface CompletionStage<T>

runAfterEither

public CompletableFuture<Void> runAfterEither(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterEither in interface CompletionStage<T>

runAfterEitherAsync

public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterEitherAsync in interface CompletionStage<T>

runAfterEitherAsync

public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other,
 Runnable action,
 Executor executor)

Specified by:

runAfterEitherAsync in interface CompletionStage<T>

toCompletableFuture

public CompletableFuture<T> toCompletableFuture()

Specified by:

toCompletableFuture in interface CompletionStage<T>

copy

public CompletableFuture<T> copy()

A new future that completes as this one does.

minimalCompletionStage

public CompletionStage<T> minimalCompletionStage()

A stage that completes as this one does, and that completing does not complete this one: a copy().

Not provided: the JDK's refusal. There the stage answered is of a class whose complete, cancel, get and the rest throw UnsupportedOperationException, and whose toCompletableFuture answers yet another copy. Here it is an ordinary future, as what completedStage(U) and failedStage(Throwable) answer is, so code that casts the stage back to a CompletableFuture, or calls toCompletableFuture() on it, and completes that, completes the stage its dependents hang off instead of being refused. What the method is called for holds either way: whoever is handed the stage cannot complete, fail or cancel the future it was made from.

toString

public String toString()

Description copied from class: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of: getClass().getName() + '@' + Integer.toHexString(hashCode())

Overrides:

toString in class Object