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.client;
019    
020    import java.io.IOException;
021    import java.util.List;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    import org.apache.hadoop.fs.FSDataInputStream;
026    import org.apache.hadoop.hdfs.DFSInputStream;
027    import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
028    import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
029    import org.apache.hadoop.hdfs.protocol.LocatedBlock;
030    
031    /**
032     * The Hdfs implementation of {@link FSDataInputStream}.
033     */
034    @InterfaceAudience.Public
035    @InterfaceStability.Evolving
036    public class HdfsDataInputStream extends FSDataInputStream {
037      public HdfsDataInputStream(DFSInputStream in) throws IOException {
038        super(in);
039      }
040    
041      /**
042       * Get the datanode from which the stream is currently reading.
043       */
044      public DatanodeInfo getCurrentDatanode() {
045        return ((DFSInputStream) in).getCurrentDatanode();
046      }
047    
048      /**
049       * Get the block containing the target position.
050       */
051      public ExtendedBlock getCurrentBlock() {
052        return ((DFSInputStream) in).getCurrentBlock();
053      }
054    
055      /**
056       * Get the collection of blocks that has already been located.
057       */
058      public synchronized List<LocatedBlock> getAllBlocks() throws IOException {
059        return ((DFSInputStream) in).getAllBlocks();
060      }
061    
062      /**
063       * Get the visible length of the file. It will include the length of the last
064       * block even if that is in UnderConstruction state.
065       * 
066       * @return The visible length of the file.
067       */
068      public long getVisibleLength() throws IOException {
069        return ((DFSInputStream) in).getFileLength();
070      }
071    
072      /**
073       * Get statistics about the reads which this DFSInputStream has done.
074       * Note that because HdfsDataInputStream is buffered, these stats may
075       * be higher than you would expect just by adding up the number of
076       * bytes read through HdfsDataInputStream.
077       */
078      public synchronized DFSInputStream.ReadStatistics getReadStatistics() {
079        return ((DFSInputStream) in).getReadStatistics();
080      }
081    }