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    
021    /**
022     * A more complex version of {@link Processor} which supports asynchronous
023     * processing of the {@link Exchange}.  Any processor can be coerced to
024     * have an {@link AsyncProcessor} interface by using the
025     * {@link org.apache.camel.impl.converter.AsyncProcessorTypeConverter#convert AsyncProcessorTypeConverter.covert}
026     * method.
027     * 
028     * @version $Revision: 36635 $
029     */
030    public interface AsyncProcessor extends Processor {
031    
032        /**
033         * Processes the message exchange.  Similar to {@link Processor#process}, but
034         * the caller supports having the exchange asynchronously processed.
035         *
036         * @param exchange the {@link Exchange} to process
037         * @param  callback the {@link AsyncCallback} will be invoked when the processing
038         *         of the exchange is completed. If the exchange is completed synchronously, then the 
039         *         callback is also invoked synchronously.  The callback should therefore be careful of
040         *         starting recursive loop.
041         *         
042         * @return true if the processing was completed synchronously.
043         */
044        boolean process(Exchange exchange, AsyncCallback callback);
045        
046    }