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.spi;
018    
019    import java.io.InputStream;
020    import java.io.OutputStream;
021    
022    import org.apache.camel.Exchange;
023    import org.apache.camel.Message;
024    
025    /**
026     * Represents a
027     * <a href="http://camel.apache.org/data-format.html">data format</a>
028     * used to marshal objects to and from streams
029     * such as Java Serialization or using JAXB2 to encode/decode objects using XML
030     * or using SOAP encoding.
031     *
032     * @version 
033     */
034    public interface DataFormat {
035    
036        /**
037         * Marshals the object to the given Stream.
038         *
039         * @param exchange  the current exchange
040         * @param graph     the object to be marshalled
041         * @param stream    the output stream to write the marshalled result to
042         * @throws Exception can be thrown
043         */
044        void marshal(Exchange exchange, Object graph, OutputStream stream) throws Exception;
045    
046        /**
047         * Unmarshals the given stream into an object.
048         * <p/>
049         * <b>Notice:</b> The result is set as body on the exchange OUT message.
050         * It is possible to mutate the OUT message provided in the given exchange parameter.
051         * For instance adding headers to the OUT message will be preserved.
052         * <p/>
053         * It's also legal to return the <b>same</b> passed <tt>exchange</tt> as is but also a
054         * {@link Message} object as well which will be used as the OUT message of <tt>exchange</tt>.
055         *
056         * @param exchange    the current exchange
057         * @param stream      the input stream with the object to be unmarshalled
058         * @return            the unmarshalled object
059         * @throws Exception can be thrown
060         */
061        Object unmarshal(Exchange exchange, InputStream stream) throws Exception;
062    }