com.arangodb.shaded.vertx.core.Future Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
* which is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
*/
package com.arangodb.shaded.vertx.core;
import com.arangodb.shaded.vertx.codegen.annotations.Fluent;
import com.arangodb.shaded.vertx.codegen.annotations.GenIgnore;
import com.arangodb.shaded.vertx.core.impl.ContextInternal;
import com.arangodb.shaded.vertx.core.impl.future.FailedFuture;
import com.arangodb.shaded.vertx.core.impl.future.SucceededFuture;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.function.Function;
/**
* Represents the result of an action that may, or may not, have occurred yet.
*
*
* @author Tim Fox
*/
public interface Future extends AsyncResult {
/**
* Create a future that hasn't completed yet and that is passed to the {@code handler} before it is returned.
*
* @param handler the handler
* @param the result type
* @return the future.
*/
static Future future(Handler> handler) {
Promise promise = Promise.promise();
try {
handler.handle(promise);
} catch (Throwable e){
promise.tryFail(e);
}
return promise.future();
}
/**
* Create a succeeded future with a null result
*
* @param the result type
* @return the future
*/
static Future succeededFuture() {
return (Future) SucceededFuture.EMPTY;
}
/**
* Created a succeeded future with the specified result.
*
* @param result the result
* @param the result type
* @return the future
*/
static Future succeededFuture(T result) {
if (result == null) {
return succeededFuture();
} else {
return new SucceededFuture<>(result);
}
}
/**
* Create a failed future with the specified failure cause.
*
* @param t the failure cause as a Throwable
* @param the result type
* @return the future
*/
static Future failedFuture(Throwable t) {
return new FailedFuture<>(t);
}
/**
* Create a failed future with the specified failure message.
*
* @param failureMessage the failure message
* @param the result type
* @return the future
*/
static Future failedFuture(String failureMessage) {
return new FailedFuture<>(failureMessage);
}
/**
* Has the future completed?
*
* It's completed if it's either succeeded or failed.
*
* @return true if completed, false if not
*/
boolean isComplete();
/**
* Add a handler to be notified of the result.
*
* WARNING: this is a terminal operation.
* If several {@code handler}s are registered, there is no guarantee that they will be invoked in order of registration.
*
* @param handler the handler that will be called with the result
* @return a reference to this, so it can be used fluently
*/
@Fluent
Future onComplete(Handler> handler);
/**
* Add a handler to be notified of the succeeded result.
*
* WARNING: this is a terminal operation.
* If several {@code handler}s are registered, there is no guarantee that they will be invoked in order of registration.
*
* @param handler the handler that will be called with the succeeded result
* @return a reference to this, so it can be used fluently
*/
@Fluent
default Future onSuccess(Handler handler) {
return onComplete(ar -> {
if (ar.succeeded()) {
handler.handle(ar.result());
}
});
}
/**
* Add a handler to be notified of the failed result.
*
* WARNING: this is a terminal operation.
* If several {@code handler}s are registered, there is no guarantee that they will be invoked in order of registration.
*
* @param handler the handler that will be called with the failed result
* @return a reference to this, so it can be used fluently
*/
@Fluent
default Future onFailure(Handler handler) {
return onComplete(ar -> {
if (ar.failed()) {
handler.handle(ar.cause());
}
});
}
/**
* The result of the operation. This will be null if the operation failed.
*
* @return the result or null if the operation failed.
*/
@Override
T result();
/**
* A Throwable describing failure. This will be null if the operation succeeded.
*
* @return the cause or null if the operation succeeded.
*/
@Override
Throwable cause();
/**
* Did it succeed?
*
* @return true if it succeded or false otherwise
*/
@Override
boolean succeeded();
/**
* Did it fail?
*
* @return true if it failed or false otherwise
*/
@Override
boolean failed();
/**
* Alias for {@link #compose(Function)}.
*/
default Future flatMap(Function> mapper) {
return compose(mapper);
}
/**
* Compose this future with a {@code mapper} function.
*
* When this future (the one on which {@code compose} is called) succeeds, the {@code mapper} will be called with
* the completed value and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.
*
* If the {@code mapper} throws an exception, the returned future will be failed with this exception.
*
* When this future fails, the failure will be propagated to the returned future and the {@code mapper}
* will not be called.
*
* @param mapper the mapper function
* @return the composed future
*/
default Future compose(Function> mapper) {
return compose(mapper, Future::failedFuture);
}
/**
* Handles a failure of this Future by returning the result of another Future.
* If the mapper fails, then the returned future will be failed with this failure.
*
* @param mapper A function which takes the exception of a failure and returns a new future.
* @return A recovered future
*/
default Future recover(Function> mapper) {
return compose(Future::succeededFuture, mapper);
}
/**
* Compose this future with a {@code successMapper} and {@code failureMapper} functions.
*
* When this future (the one on which {@code compose} is called) succeeds, the {@code successMapper} will be called with
* the completed value and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.
*
* When this future (the one on which {@code compose} is called) fails, the {@code failureMapper} will be called with
* the failure and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.
*
* If any mapper function throws an exception, the returned future will be failed with this exception.
*
* @param successMapper the function mapping the success
* @param failureMapper the function mapping the failure
* @return the composed future
*/
Future compose(Function> successMapper, Function> failureMapper);
/**
* Transform this future with a {@code mapper} functions.
*
* When this future (the one on which {@code transform} is called) completes, the {@code mapper} will be called with
* the async result and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.
*
* If any mapper function throws an exception, the returned future will be failed with this exception.
*
* @param mapper the function mapping the future
* @return the transformed future
*/
Future transform(Function, Future> mapper);
/**
* Compose this future with a {@code mapper} that will be always be called.
*
* When this future (the one on which {@code eventually} is called) completes, the {@code mapper} will be called
* and this mapper returns another future object. This returned future completion will complete the future returned
* by this method call with the original result of the future.
*
*
The outcome of the future returned by the {@code mapper} will not influence the nature
* of the returned future.
*
* @param mapper the function returning the future.
* @return the composed future
*/
Future eventually(Function> mapper);
/**
* Apply a {@code mapper} function on this future.
*
* When this future succeeds, the {@code mapper} will be called with the completed value and this mapper
* returns a value. This value will complete the future returned by this method call.
*
* If the {@code mapper} throws an exception, the returned future will be failed with this exception.
*
* When this future fails, the failure will be propagated to the returned future and the {@code mapper}
* will not be called.
*
* @param mapper the mapper function
* @return the mapped future
*/
Future map(Function mapper);
/**
* Map the result of a future to a specific {@code value}.
*
* When this future succeeds, this {@code value} will complete the future returned by this method call.
*
* When this future fails, the failure will be propagated to the returned future.
*
* @param value the value that eventually completes the mapped future
* @return the mapped future
*/
Future map(V value);
/**
* Map the result of a future to {@code null}.
*
* This is a conveniency for {@code future.map((T) null)} or {@code future.map((Void) null)}.
*
* When this future succeeds, {@code null} will complete the future returned by this method call.
*
* When this future fails, the failure will be propagated to the returned future.
*
* @return the mapped future
*/
@Override
default Future mapEmpty() {
return (Future) AsyncResult.super.mapEmpty();
}
/**
* Apply a {@code mapper} function on this future.
*
* When this future fails, the {@code mapper} will be called with the completed value and this mapper
* returns a value. This value will complete the future returned by this method call.
*
* If the {@code mapper} throws an exception, the returned future will be failed with this exception.
*
* When this future succeeds, the result will be propagated to the returned future and the {@code mapper}
* will not be called.
*
* @param mapper the mapper function
* @return the mapped future
*/
Future otherwise(Function mapper);
/**
* Map the failure of a future to a specific {@code value}.
*
* When this future fails, this {@code value} will complete the future returned by this method call.
*
* When this future succeeds, the result will be propagated to the returned future.
*
* @param value the value that eventually completes the mapped future
* @return the mapped future
*/
Future otherwise(T value);
/**
* Map the failure of a future to {@code null}.
*
* This is a convenience for {@code future.otherwise((T) null)}.
*
* When this future fails, the {@code null} value will complete the future returned by this method call.
*
* When this future succeeds, the result will be propagated to the returned future.
*
* @return the mapped future
*/
default Future otherwiseEmpty() {
return (Future) AsyncResult.super.otherwiseEmpty();
}
/**
* Invokes the given {@code handler} upon completion.
*
* If the {@code handler} throws an exception, the returned future will be failed with this exception.
*
* @param handler invoked upon completion of this future
* @return a future completed after the {@code handler} has been invoked
*/
default Future andThen(Handler> handler) {
return transform(ar -> {
handler.handle(ar);
return (Future) ar;
});
}
/**
* Bridges this Vert.x future to a {@link CompletionStage} instance.
*
* The {@link CompletionStage} handling methods will be called from the thread that resolves this future.
*
* @return a {@link CompletionStage} that completes when this future resolves
*/
@GenIgnore
default CompletionStage toCompletionStage() {
CompletableFuture completableFuture = new CompletableFuture<>();
onComplete(ar -> {
if (ar.succeeded()) {
completableFuture.complete(ar.result());
} else {
completableFuture.completeExceptionally(ar.cause());
}
});
return completableFuture;
}
/**
* Bridges a {@link CompletionStage} object to a Vert.x future instance.
*
* The Vert.x future handling methods will be called from the thread that completes {@code completionStage}.
*
* @param completionStage a completion stage
* @param the result type
* @return a Vert.x future that resolves when {@code completionStage} resolves
*/
@GenIgnore
static Future fromCompletionStage(CompletionStage completionStage) {
Promise promise = Promise.promise();
completionStage.whenComplete((value, err) -> {
if (err != null) {
promise.fail(err);
} else {
promise.complete(value);
}
});
return promise.future();
}
/**
* Bridges a {@link CompletionStage} object to a Vert.x future instance.
*
* The Vert.x future handling methods will be called on the provided {@code context}.
*
* @param completionStage a completion stage
* @param context a Vert.x context to dispatch to
* @param the result type
* @return a Vert.x future that resolves when {@code completionStage} resolves
*/
@GenIgnore
static Future fromCompletionStage(CompletionStage completionStage, Context context) {
Promise promise = ((ContextInternal) context).promise();
completionStage.whenComplete((value, err) -> {
if (err != null) {
promise.fail(err);
} else {
promise.complete(value);
}
});
return promise.future();
}
}