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     */
017    package org.apache.camel;
018    
019    /**
020     * An <b>asynchronous</b> processor which can process an {@link Exchange} in an asynchronous fashion
021     * and signal completion by invoking the {@link AsyncCallback}.
022     * <p/>
023     * Any processor can be coerced to have an {@link AsyncProcessor} interface by using the
024     * {@link org.apache.camel.impl.converter.AsyncProcessorTypeConverter#convert AsyncProcessorTypeConverter.covert}
025     * method.
026     *
027     * @version 
028     */
029    public 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    }