Package 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:

java.io.Closeable, java.io.DataInput, java.lang.AutoCloseable, org.apache.hadoop.fs.ByteBufferPositionedReadable, org.apache.hadoop.fs.ByteBufferReadable, org.apache.hadoop.fs.CanSetDropBehind, org.apache.hadoop.fs.CanSetReadahead, org.apache.hadoop.fs.CanUnbuffer, org.apache.hadoop.fs.HasEnhancedByteBufferAccess, org.apache.hadoop.fs.HasFileDescriptor, org.apache.hadoop.fs.PositionedReadable, org.apache.hadoop.fs.Seekable, org.apache.hadoop.fs.statistics.IOStatisticsSource, org.apache.hadoop.fs.StreamCapabilities

Direct Known Subclasses:

DFSClient.DFSDataInputStream

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

The Hdfs implementation of FSDataInputStream.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.fs.FSDataInputStream

org.apache.hadoop.fs.FSDataInputStream.FadviseType

Nested classes/interfaces inherited from interface org.apache.hadoop.fs.StreamCapabilities

org.apache.hadoop.fs.StreamCapabilities.StreamCapability

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Fields inherited from interface org.apache.hadoop.fs.StreamCapabilities

ABORTABLE_STREAM, DROPBEHIND, HFLUSH, HSYNC, IOSTATISTICS, IOSTATISTICS_CONTEXT, PREADBYTEBUFFER, READAHEAD, READBYTEBUFFER, UNBUFFER, VECTOREDIO

Constructor Summary

Constructors

Constructor	Description
HdfsDataInputStream(org.apache.hadoop.crypto.CryptoInputStream in)
HdfsDataInputStream(DFSInputStream in)

Method Summary

Modifier and Type	Method	Description
void	clearReadStatistics()
java.util.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.
ReadStatistics	getReadStatistics()	Get statistics about the reads which this DFSInputStream has done.
long	getVisibleLength()	Get the visible length of the file.
java.io.InputStream	getWrappedStream()	Get a reference to the wrapped output stream.

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

adviseFile, getChunkSize, getFidServers, getFidStr, getFileDescriptor, getFileLength, getIOStatistics, getPos, hasCapability, maxReadSizeForVectorReads, minSeekForVectorReads, read, read, read, read, read, readFully, readFully, readFully, readVectored, releaseBuffer, seek, seekToNewSource, setDropBehind, setReadahead, toString, unbuffer

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.io.InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo

Methods inherited from class java.lang.Object

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

Constructor Detail

HdfsDataInputStream

public HdfsDataInputStream(DFSInputStream in)

HdfsDataInputStream

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

Method Detail

getWrappedStream

public java.io.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 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 java.util.List<LocatedBlock> getAllBlocks()
                                          throws java.io.IOException

Get the collection of blocks that has already been located.

Throws:

java.io.IOException

getVisibleLength

public long getVisibleLength()

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.

getReadStatistics

public 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.

clearReadStatistics

public void clearReadStatistics()