com.google.common.util.concurrent.AsyncFunction.java Source code

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Here is the source code for com.google.common.util.concurrent.AsyncFunction.java

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/*
 * 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 com.google.common.annotations.GwtCompatible;

import java.util.concurrent.Future;

import javax.annotation.Nullable;

/**
 * Transforms a value, possibly asynchronously. For an example usage and more information, see
 * {@link Futures#transformAsync(ListenableFuture, AsyncFunction)}.
 *
 * @author Chris Povirk
 * @since 11.0
 */
@GwtCompatible
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(@Nullable I input) throws Exception;
}