001/*
002 * Copyright (C) 2009 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.util.concurrent;
018
019import javax.annotation.Nullable;
020
021/**
022 * A {@link ListenableFuture} whose result may be set by a {@link #set(Object)}
023 * or {@link #setException(Throwable)} call. It may also be cancelled.
024 *
025 * @author Sven Mawson
026 * @since 9.0 (in 1.0 as {@code ValueFuture})
027 */
028public final class SettableFuture<V> extends AbstractFuture<V> {
029
030  /**
031   * Creates a new {@code SettableFuture} in the default state.
032   */
033  public static <V> SettableFuture<V> create() {
034    return new SettableFuture<V>();
035  }
036
037  /**
038   * Explicit private constructor, use the {@link #create} factory method to
039   * create instances of {@code SettableFuture}.
040   */
041  private SettableFuture() {}
042
043  /**
044   * Sets the value of this future.  This method will return {@code true} if
045   * the value was successfully set, or {@code false} if the future has already
046   * been set or cancelled.
047   *
048   * @param value the value the future should hold.
049   * @return true if the value was successfully set.
050   */
051  @Override
052  public boolean set(@Nullable V value) {
053    return super.set(value);
054  }
055
056  /**
057   * Sets the future to having failed with the given exception. This exception
058   * will be wrapped in an {@code ExecutionException} and thrown from the {@code
059   * get} methods. This method will return {@code true} if the exception was
060   * successfully set, or {@code false} if the future has already been set or
061   * cancelled.
062   *
063   * @param throwable the exception the future should hold.
064   * @return true if the exception was successfully set.
065   */
066  @Override
067  public boolean setException(Throwable throwable) {
068    return super.setException(throwable);
069  }
070}