001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel;
018
019import java.util.concurrent.CompletableFuture;
020
021/**
022 * An <b>asynchronous</b> processor which can process an {@link Exchange} in an asynchronous fashion
023 * and signal completion by invoking the {@link AsyncCallback}.
024 * <p/>
025 * Any processor can be coerced to have an {@link AsyncProcessor} interface by using the
026 * {@link org.apache.camel.support.AsyncProcessorConverterHelper#convert AsyncProcessorConverterHelper.convert}
027 * method.
028 */
029public interface AsyncProcessor extends Processor {
030
031    /**
032     * Processes the message exchange.
033     * Similar to {@link Processor#process}, but the caller supports having the exchange asynchronously processed.
034     * <p/>
035     * If there was a failure processing then the caused {@link Exception} would be set on the {@link Exchange}.
036     *
037     * @param exchange the message exchange
038     * @param callback the {@link AsyncCallback} will be invoked when the processing of the exchange is completed.
039     *                 If the exchange is completed synchronously, then the callback is also invoked synchronously.
040     *                 The callback should therefore be careful of starting recursive loop.
041     * @return (doneSync) <tt>true</tt> to continue execute synchronously, <tt>false</tt> to continue being executed asynchronously
042     */
043    boolean process(Exchange exchange, AsyncCallback callback);
044
045    CompletableFuture<Exchange> processAsync(Exchange exchange);
046
047}