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
017 package com.google.common.util.concurrent;
018
019 import 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 */
028 public 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 }