/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.camel;



/**
 * A more complex version of {@see Processor} which supports asynchronous
 * processing of the {@see Exchange}.  Any processor can be coerced to
 * have an {@see AsyncProcessor} interface by using the {@see AsyncProcessorTypeConverter.convert()}
 * method.
 * 
 * @version $Revision: 21091 $
 */
public interface AsyncProcessor extends Processor {

    /**
     * Processes the message exchange.  Similar to {@see Processor.process}, but
     * the caller supports having the exchange asynchronously processed.
     *
     * @param exchange the exchange to process
     * @param  callback The @{see AsyncCallback} will be invoked when the processing
     *         of the exchange is completed. If the exchange is completed synchronously, then the 
     *         callback is also invoked synchronously.  The callback should therefore be careful of
     *         starting recursive loop.
     *         
     * @return true if the processing was completed synchronously.
     */
    boolean process(Exchange exchange, AsyncCallback callback);
    
}
