001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.server.datanode.web.resources;
019    
020    import java.io.IOException;
021    import java.io.OutputStream;
022    import java.lang.annotation.Annotation;
023    import java.lang.reflect.Type;
024    
025    import javax.ws.rs.core.MediaType;
026    import javax.ws.rs.core.MultivaluedMap;
027    import javax.ws.rs.ext.MessageBodyWriter;
028    import javax.ws.rs.ext.Provider;
029    
030    import org.apache.hadoop.hdfs.DFSClient;
031    import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
032    import org.apache.hadoop.io.IOUtils;
033    
034    /**
035     * A response entity for a HdfsDataInputStream.
036     */
037    public class OpenEntity {
038      private final HdfsDataInputStream in;
039      private final long length;
040      private final DFSClient dfsclient;
041      
042      OpenEntity(final HdfsDataInputStream in, final long length,
043          final DFSClient dfsclient) {
044        this.in = in;
045        this.length = length;
046        this.dfsclient = dfsclient;
047      }
048      
049      /**
050       * A {@link MessageBodyWriter} for {@link OpenEntity}.
051       */
052      @Provider
053      public static class Writer implements MessageBodyWriter<OpenEntity> {
054    
055        @Override
056        public boolean isWriteable(Class<?> clazz, Type genericType,
057            Annotation[] annotations, MediaType mediaType) {
058          return clazz == OpenEntity.class
059              && MediaType.APPLICATION_OCTET_STREAM_TYPE.isCompatible(mediaType);
060        }
061    
062        @Override
063        public long getSize(OpenEntity e, Class<?> type, Type genericType,
064            Annotation[] annotations, MediaType mediaType) {
065          return e.length;
066        }
067    
068        @Override
069        public void writeTo(OpenEntity e, Class<?> type, Type genericType,
070            Annotation[] annotations, MediaType mediaType,
071            MultivaluedMap<String, Object> httpHeaders, OutputStream out
072            ) throws IOException {
073          try {
074            IOUtils.copyBytes(e.in, out, e.length, false);
075          } finally {
076            IOUtils.cleanup(DatanodeWebHdfsMethods.LOG, e.in);
077            IOUtils.cleanup(DatanodeWebHdfsMethods.LOG, e.dfsclient);
078          }
079        }
080      }
081    }