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.Executor; 022 023 /** 024 * A {@link ForwardingFuture} that also implements {@link ListenableFuture}. 025 * Subclasses will have to provide a delegate {@link ListenableFuture} through 026 * the {@link #delegate()} method. 027 * 028 * @param <V> The result type returned by this Future's <tt>get</tt> method 029 * 030 * @author Shardul Deo 031 * @since 4 032 */ 033 @Beta 034 public abstract class ForwardingListenableFuture<V> extends ForwardingFuture<V> 035 implements ListenableFuture<V> { 036 037 /** Constructor for use by subclasses. */ 038 protected ForwardingListenableFuture() {} 039 040 @Override 041 protected abstract ListenableFuture<V> delegate(); 042 043 @Override 044 public void addListener(Runnable listener, Executor exec) { 045 delegate().addListener(listener, exec); 046 } 047 }