1/*
2 * Copyright (C) 2009 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.util.concurrent;
18
19import javax.annotation.Nullable;
20
21/**
22 * A {@link ListenableFuture} whose result may be set by a {@link #set(Object)}
23 * or {@link #setException(Throwable)} call. It may also be cancelled.
24 *
25 * @author Sven Mawson
26 * @since 9.0 (in 1.0 as {@code ValueFuture})
27 */
28public final class SettableFuture<V> extends AbstractFuture<V> {
29
30  /**
31   * Creates a new {@code SettableFuture} in the default state.
32   */
33  public static <V> SettableFuture<V> create() {
34    return new SettableFuture<V>();
35  }
36
37  /**
38   * Explicit private constructor, use the {@link #create} factory method to
39   * create instances of {@code SettableFuture}.
40   */
41  private SettableFuture() {}
42
43  /**
44   * Sets the value of this future.  This method will return {@code true} if
45   * the value was successfully set, or {@code false} if the future has already
46   * been set or cancelled.
47   *
48   * @param value the value the future should hold.
49   * @return true if the value was successfully set.
50   */
51  @Override
52  public boolean set(@Nullable V value) {
53    return super.set(value);
54  }
55
56  /**
57   * Sets the future to having failed with the given exception. This exception
58   * will be wrapped in an {@code ExecutionException} and thrown from the {@code
59   * get} methods. This method will return {@code true} if the exception was
60   * successfully set, or {@code false} if the future has already been set or
61   * cancelled.
62   *
63   * @param throwable the exception the future should hold.
64   * @return true if the exception was successfully set.
65   */
66  @Override
67  public boolean setException(Throwable throwable) {
68    return super.setException(throwable);
69  }
70}
71