1 /* 2 * Copyright (C) 2011 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.util.concurrent; 18 19 import java.util.concurrent.Future; 20 21 /** 22 * Transforms a value, possibly asynchronously. For an example usage and more 23 * information, see {@link Futures#transform(ListenableFuture, AsyncFunction)}. 24 * 25 * @author Chris Povirk 26 * @since 11.0 27 */ 28 public interface AsyncFunction<I, O> { 29 /** 30 * Returns an output {@code Future} to use in place of the given {@code 31 * input}. The output {@code Future} need not be {@linkplain Future#isDone 32 * done}, making {@code AsyncFunction} suitable for asynchronous derivations. 33 * 34 * <p>Throwing an exception from this method is equivalent to returning a 35 * failing {@code Future}. 36 */ 37 ListenableFuture<O> apply(I input) throws Exception; 38 } 39
