001/* 002 * Copyright (C) 2011 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 005 * in compliance with the License. You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software distributed under the License 010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 011 * or implied. See the License for the specific language governing permissions and limitations under 012 * the License. 013 */ 014 015package com.google.common.util.concurrent; 016 017import com.google.common.annotations.GwtCompatible; 018import java.util.concurrent.ExecutionException; 019import java.util.concurrent.Future; 020import org.checkerframework.checker.nullness.qual.Nullable; 021 022/** 023 * A callback for accepting the results of a {@link java.util.concurrent.Future} computation 024 * asynchronously. 025 * 026 * <p>To attach to a {@link ListenableFuture} use {@link Futures#addCallback}. 027 * 028 * @author Anthony Zana 029 * @since 10.0 030 */ 031@GwtCompatible 032@ElementTypesAreNonnullByDefault 033public interface FutureCallback<V extends @Nullable Object> { 034 /** Invoked with the result of the {@code Future} computation when it is successful. */ 035 void onSuccess(@ParametricNullness V result); 036 037 /** 038 * Invoked when a {@code Future} computation fails or is canceled. 039 * 040 * <p>If the future's {@link Future#get() get} method throws an {@link ExecutionException}, then 041 * the cause is passed to this method. Any other thrown object is passed unaltered. 042 */ 043 void onFailure(Throwable t); 044}