/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.util.concurrent;
import java.util.concurrent.Future;
/**
* Transforms a value, possibly asynchronously. For an example usage and more
* information, see {@link Futures#transform(ListenableFuture, AsyncFunction)}.
*
* @author Chris Povirk
* @since 11.0
*/
public interface AsyncFunction<I, O> {
/**
* Returns an output {@code Future} to use in place of the given {@code
* input}. The output {@code Future} need not be {@linkplain Future#isDone
* done}, making {@code AsyncFunction} suitable for asynchronous derivations.
*
* <p>Throwing an exception from this method is equivalent to returning a
* failing {@code Future}.
*/
ListenableFuture<O> apply(I input) throws Exception;
}