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 IOException {
049            return new StreamSourceCache(source);
050        }
051        
052        @Converter
053        public StreamCache convertToStreamCache(StringSource source) {
054            //no need to do stream caching for a StringSource
055            return null;
056        }
057        
058        @Converter
059        public StreamCache convertToStreamCache(BytesSource source) {
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() {
087            }
088    
089            public SourceCache(String text) {
090                super(text);
091            }
092    
093            public void reset() {
094                // do nothing here
095            }
096    
097        }
098        
099        /*
100         * {@link StreamCache} implementation for Cache the StreamSource {@link StreamSource}s
101         */
102        private class StreamSourceCache extends StreamSource implements StreamCache {
103            InputStreamCache inputStreamCache;
104            ReaderCache readCache;
105            
106            public StreamSourceCache(StreamSource source) throws IOException {
107                if (source.getInputStream() != null) {
108                    inputStreamCache = new InputStreamCache(IOConverter.toBytes(source.getInputStream()));
109                    setInputStream(inputStreamCache);
110                    setSystemId(source.getSystemId());
111                }
112                if (source.getReader() != null) {
113                    readCache = new ReaderCache(IOConverter.toString(source.getReader()));
114                    setReader(readCache);
115                }
116            }
117            public void reset() {
118                if (inputStreamCache != null) {
119                    inputStreamCache.reset();
120                }
121                if (readCache != null) {
122                    readCache.reset();
123                }            
124            }
125            
126        }
127    
128        private class InputStreamCache extends ByteArrayInputStream implements StreamCache {
129    
130            public InputStreamCache(byte[] data) {
131                super(data);
132            }
133    
134        }
135    
136        private class ReaderCache extends StringReader implements StreamCache {
137    
138            public ReaderCache(String s) {
139                super(s);
140            }
141    
142            public void reset() {
143                try {
144                    super.reset();
145                } catch (IOException e) {
146                    LOG.warn("Exception is thrown when resets the ReaderCache", e);
147                }
148            }
149    
150            public void close() {
151                // Do not release the string for caching
152            }
153    
154        }
155    
156    
157    }