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, AutoCloseable, ByteBufferReadable, CanSetDropBehind, CanSetReadahead, HasFileDescriptor, PositionedReadable, Seekable

Direct Known Subclasses:

DFSClient.DFSDataInputStream

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HdfsDataInputStream
extends FSDataInputStream

The Hdfs implementation of FSDataInputStream.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
HdfsDataInputStream(DFSInputStream in)

Method Summary

Methods

Modifier and Type	Method and Description
List<LocatedBlock>	getAllBlocks() Get the collection of blocks that has already been located.
ExtendedBlock	getCurrentBlock() Get the block containing the target position.
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.

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

getFileDescriptor, getPos, getWrappedStream, read, read, readFully, readFully, 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

Methods inherited from interface java.io.Closeable

close

Constructor Detail

HdfsDataInputStream

public HdfsDataInputStream(DFSInputStream in)
                    throws IOException

Throws:

IOException

Method Detail

getCurrentDatanode

public DatanodeInfo getCurrentDatanode()

Get the datanode from which the stream is currently reading.

getCurrentBlock

public ExtendedBlock getCurrentBlock()

Get the block containing the target position.

getAllBlocks

public List<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.