001    /*
002     * Copyright (C) 2009 Google Inc.
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 com.google.common.annotations.Beta;
020    
021    import java.util.concurrent.Callable;
022    
023    import javax.annotation.Nullable;
024    
025    /**
026     * Static utility methods pertaining to the {@link Callable} interface.
027     *
028     * @author Isaac Shum
029     * @since 1
030     */
031    @Beta
032    public final class Callables {
033      private Callables() {}
034    
035      /**
036       * Creates a {@code Callable} which immediately returns a preset value each
037       * time it is called.
038       */
039      public static <T> Callable<T> returning(final @Nullable T value) {
040        return new Callable<T>() {
041          @Override public T call() {
042            return value;
043          }
044        };
045      }
046    }