1 /*
2 * Copyright (C) 2009 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14
15 package com.google.common.util.concurrent;
16
17 import com.google.common.annotations.GwtCompatible;
18 import com.google.errorprone.annotations.CanIgnoreReturnValue;
19 import org.checkerframework.checker.nullness.qual.Nullable;
20
21 /**
22 * A {@link ListenableFuture} whose result can be set by a {@link #set(Object)}, {@link
23 * #setException(Throwable)} or {@link #setFuture(ListenableFuture)} call. It can also, like any
24 * other {@code Future}, be {@linkplain #cancel cancelled}.
25 *
26 * <p>{@code SettableFuture} is the recommended {@code ListenableFuture} implementation when your
27 * task cannot be implemented with {@link ListeningExecutorService}, the various {@link Futures}
28 * utility methods, or {@link ListenableFutureTask}. Those APIs have less opportunity for developer
29 * error. If your needs are more complex than {@code SettableFuture} supports, use {@link
30 * AbstractFuture}, which offers an extensible version of the API.
31 *
32 * @author Sven Mawson
33 * @since 9.0 (in 1.0 as {@code ValueFuture})
34 */
35 @GwtCompatible
36 public final class SettableFuture<V> extends AbstractFuture.TrustedFuture<V> {
37 /**
38 * Creates a new {@code SettableFuture} that can be completed or cancelled by a later method call.
39 */
40 public static <V> SettableFuture<V> create() {
41 return new SettableFuture<V>();
42 }
43
44 @CanIgnoreReturnValue
45 @Override
46 public boolean set(@Nullable V value) {
47 return super.set(value);
48 }
49
50 @CanIgnoreReturnValue
51 @Override
52 public boolean setException(Throwable throwable) {
53 return super.setException(throwable);
54 }
55
56 @CanIgnoreReturnValue
57 @Override
58 public boolean setFuture(ListenableFuture<? extends V> future) {
59 return super.setFuture(future);
60 }
61
62 private SettableFuture() {}
63 }