org.opendaylight.yangtools.util.concurrent.FluentFutures Maven / Gradle / Ivy
/*
* Copyright (c) 2018 Pantheon Technologies, s.r.o. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.util.concurrent;
import static java.util.Objects.requireNonNull;
import com.google.common.annotations.Beta;
import com.google.common.util.concurrent.FluentFuture;
import com.google.common.util.concurrent.Futures;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import org.eclipse.jdt.annotation.NonNullByDefault;
import org.eclipse.jdt.annotation.Nullable;
/**
* Utility methods for working with {@link FluentFuture}s. This class provides methods which should really live in
* Guava's, for example in {@link Futures}, as the implementations provided by {@link Futures#immediateFuture(Object)}
* and others already implement {@link FluentFuture} and so getting a FluentFuture is a matter of pure boiler-plate.
*
*
* {@link #immediateBooleanFluentFuture(boolean)}, {@link #immediateBooleanFluentFuture(Boolean)},
* {@link #immediateFalseFluentFuture()}, {@link #immediateTrueFluentFuture()} and {@link #immediateNullFluentFuture()}
* provide low-cardinality constants, which are generally useful to reduce allocations.
*
* @author Robert Varga
*/
@Beta
@NonNullByDefault
@SuppressWarnings("null")
public final class FluentFutures {
private static final FluentFuture CANCELLED_FUTURE = FluentFuture.from(Futures.immediateCancelledFuture());
private static final FluentFuture NULL_FUTURE = FluentFuture.from(Futures.immediateFuture(null));
private static final FluentFuture FALSE_FUTURE = FluentFuture.from(Futures.immediateFuture(Boolean.FALSE));
private static final FluentFuture TRUE_FUTURE = FluentFuture.from(Futures.immediateFuture(Boolean.TRUE));
private FluentFutures() {
}
/**
* Return a {@link FluentFuture} which is immediately {@link Future#cancel(boolean)}led.
*
* @return An immediately-cancelled FluentFuture.
*/
@SuppressWarnings("unchecked")
public static FluentFuture immediateCancelledFluentFuture() {
return (FluentFuture) CANCELLED_FUTURE;
}
/**
* Return a {@link FluentFuture} which is immediately failed, reporting specified failure {@code cause}.
*
* @param cause failure cause
* @return An immediately-failed FluentFuture.
* @throws NullPointerException if {@code cause} is null
*/
public static FluentFuture immediateFailedFluentFuture(final Throwable cause) {
return FluentFuture.from(Futures.immediateFailedFuture(requireNonNull(cause)));
}
/**
* Return a {@link FluentFuture} which is immediately completed, reporting specified {@code result}.
*
* @param result result of the future
* @return An immediately-completed FluentFuture.
* @throws NullPointerException if {@code result} is null
*/
public static FluentFuture immediateFluentFuture(final T result) {
return FluentFuture.from(Futures.immediateFuture(requireNonNull(result)));
}
/**
* Return a {@link FluentFuture} which is immediately completed with a {@code null} result.
*
* @return An immediately-completed FluentFuture.
*/
@SuppressWarnings("unchecked")
public static <@Nullable T> FluentFuture immediateNullFluentFuture() {
return (FluentFuture) NULL_FUTURE;
}
/**
* Return a {@link FluentFuture} which is immediately completed, reporting specified {@code result}.
*
* @param result boolean result
* @return An immediately-completed FluentFuture reporting specified {@code result}
* @throws NullPointerException if {@code result} is null
*/
public static FluentFuture immediateBooleanFluentFuture(final Boolean result) {
return immediateBooleanFluentFuture(result.booleanValue());
}
/**
* Return a {@link FluentFuture} which is immediately completed, reporting specified {@code result}.
*
* @param result boolean result
* @return An immediately-completed FluentFuture reporting specified {@code result}
*/
public static FluentFuture immediateBooleanFluentFuture(final boolean result) {
return result ? TRUE_FUTURE : FALSE_FUTURE;
}
/**
* Return a {@link FluentFuture} which is immediately completed, reporting specified {@link Boolean#TRUE}.
*
* @return An immediately-completed FluentFuture reporting {@link Boolean#TRUE}
*/
public static FluentFuture immediateTrueFluentFuture() {
return TRUE_FUTURE;
}
/**
* Return a {@link FluentFuture} which is immediately completed, reporting specified {@link Boolean#TRUE}.
*
* @return An immediately-completed FluentFuture reporting {@link Boolean#TRUE}
*/
public static FluentFuture immediateFalseFluentFuture() {
return FALSE_FUTURE;
}
/**
* Submit a {@link Callable} to specified {@link Executor} and return a {@link FluentFuture} that completes with the
* result of the {@link Callable}.
*
* @param Callable return type
* @param callable The Callable to call
* @param executor The Executor to use
* @throws NullPointerException if any argument is {@code null}
*/
public static FluentFuture submit(final Callable callable, final Executor executor) {
return FluentFuture.from(Futures.submit(callable, executor));
}
}