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.converter.stream;
018    
019    import java.io.ByteArrayInputStream;
020    import java.io.IOException;
021    import java.io.InputStream;
022    import java.io.Reader;
023    import java.io.StringReader;
024    
025    import javax.xml.transform.TransformerException;
026    import javax.xml.transform.sax.SAXSource;
027    import javax.xml.transform.stream.StreamSource;
028    
029    import org.apache.camel.Converter;
030    import org.apache.camel.converter.IOConverter;
031    import org.apache.camel.converter.jaxp.BytesSource;
032    import org.apache.camel.converter.jaxp.StringSource;
033    import org.apache.camel.converter.jaxp.XmlConverter;
034    import org.apache.commons.logging.Log;
035    import org.apache.commons.logging.LogFactory;
036    
037    /**
038     * A set of {@link Converter} methods for wrapping stream-based messages in a {@link StreamCache}
039     * implementation to ensure message re-readability (eg multicasting, retrying)
040     */
041    @Converter
042    public class StreamCacheConverter {
043        private static final transient Log LOG = LogFactory.getLog(StreamCacheConverter.class);
044    
045        private XmlConverter converter = new XmlConverter();
046    
047        @Converter
048        public StreamCache convertToStreamCache(StreamSource source) throws TransformerException {
049            return new SourceCache(converter.toString(source));
050        }
051        
052        @Converter
053        public StreamCache convertToStreamCache(StringSource source) throws TransformerException {
054            //no need to do stream caching for a StringSource
055            return null;
056        }
057        
058        @Converter
059        public StreamCache convertToStreamCache(BytesSource source) throws TransformerException {
060            //no need to do stream caching for a BytesSource
061            return null;
062        }
063        
064        @Converter
065        public StreamCache convertToStreamCache(SAXSource source) throws TransformerException {
066            return new SourceCache(converter.toString(source));
067        }
068    
069        @Converter
070        public StreamCache convertToStreamCache(InputStream stream) throws IOException {
071            return new InputStreamCache(IOConverter.toBytes(stream));
072        }
073    
074        @Converter
075        public StreamCache convertToStreamCache(Reader reader) throws IOException {
076            return new ReaderCache(IOConverter.toString(reader));
077        }
078    
079        /*
080         * {@link StreamCache} implementation for {@link Source}s
081         */
082        private class SourceCache extends StringSource implements StreamCache {
083    
084            private static final long serialVersionUID = 4147248494104812945L;
085    
086            public SourceCache(String text) {
087                super(text);
088            }
089    
090            public void reset() {
091                // do nothing here
092            }
093    
094        }
095    
096        private class InputStreamCache extends ByteArrayInputStream implements StreamCache {
097    
098            public InputStreamCache(byte[] data) {
099                super(data);
100            }
101    
102        }
103    
104        private class ReaderCache extends StringReader implements StreamCache {
105    
106            public ReaderCache(String s) {
107                super(s);
108            }
109    
110            public void reset() {
111                try {
112                    super.reset();
113                } catch (IOException e) {
114                    LOG.warn("Exception is thrown when resets the ReaderCache", e);
115                }
116            }
117    
118            public void close() {
119                // Do not release the string for caching
120            }
121    
122        }
123    
124    
125    }