org.apache.hadoop.hdfs.client
Class HdfsDataInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          java.io.DataInputStream
              org.apache.hadoop.fs.FSDataInputStream
                  org.apache.hadoop.hdfs.client.HdfsDataInputStream

All Implemented Interfaces:

Closeable, DataInput, org.apache.hadoop.fs.ByteBufferReadable, org.apache.hadoop.fs.CanSetDropBehind, org.apache.hadoop.fs.CanSetReadahead, org.apache.hadoop.fs.HasEnhancedByteBufferAccess, org.apache.hadoop.fs.HasFileDescriptor, org.apache.hadoop.fs.PositionedReadable, org.apache.hadoop.fs.Seekable

Direct Known Subclasses:

DFSClient.DFSDataInputStream

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HdfsDataInputStream
extends org.apache.hadoop.fs.FSDataInputStream

The Hdfs implementation of FSDataInputStream.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

HdfsDataInputStream(org.apache.hadoop.crypto.CryptoInputStream in)

HdfsDataInputStream(org.apache.hadoop.hdfs.DFSInputStream in)

Method Summary

List<org.apache.hadoop.hdfs.protocol.LocatedBlock>	getAllBlocks() Get the collection of blocks that has already been located.
org.apache.hadoop.hdfs.protocol.ExtendedBlock	getCurrentBlock() Get the block containing the target position.
org.apache.hadoop.hdfs.protocol.DatanodeInfo	getCurrentDatanode() Get the datanode from which the stream is currently reading.
DFSInputStream.ReadStatistics	getReadStatistics() Get statistics about the reads which this DFSInputStream has done.
long	getVisibleLength() Get the visible length of the file.
InputStream	getWrappedStream() Get a reference to the wrapped output stream.

Methods inherited from class org.apache.hadoop.fs.FSDataInputStream

getFileDescriptor, getPos, read, read, read, read, readFully, readFully, releaseBuffer, seek, seekToNewSource, setDropBehind, setReadahead

Methods inherited from class java.io.DataInputStream

read, read, readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, readUTF, skipBytes

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HdfsDataInputStream

public HdfsDataInputStream(org.apache.hadoop.hdfs.DFSInputStream in)
                    throws IOException

Throws:

IOException

HdfsDataInputStream

public HdfsDataInputStream(org.apache.hadoop.crypto.CryptoInputStream in)
                    throws IOException

Throws:

IOException

Method Detail

getWrappedStream

public InputStream getWrappedStream()

Get a reference to the wrapped output stream. We always want to return the actual underlying InputStream, even when we're using a CryptoStream. e.g. in the delegated methods below.

Overrides:

getWrappedStream in class org.apache.hadoop.fs.FSDataInputStream

Returns:

the underlying output stream

getCurrentDatanode

public org.apache.hadoop.hdfs.protocol.DatanodeInfo getCurrentDatanode()

Get the datanode from which the stream is currently reading.

getCurrentBlock

public org.apache.hadoop.hdfs.protocol.ExtendedBlock getCurrentBlock()

Get the block containing the target position.

getAllBlocks

public List<org.apache.hadoop.hdfs.protocol.LocatedBlock> getAllBlocks()
                                                                throws IOException

Get the collection of blocks that has already been located.

Throws:

IOException

getVisibleLength

public long getVisibleLength()
                      throws IOException

Get the visible length of the file. It will include the length of the last block even if that is in UnderConstruction state.

Returns:

The visible length of the file.

Throws:

IOException

getReadStatistics

public DFSInputStream.ReadStatistics getReadStatistics()

Get statistics about the reads which this DFSInputStream has done. Note that because HdfsDataInputStream is buffered, these stats may be higher than you would expect just by adding up the number of bytes read through HdfsDataInputStream.