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, ByteBufferPositionedReadable, ByteBufferReadable, CanSetDropBehind, CanSetReadahead, CanUnbuffer, org.apache.hadoop.fs.HasEnhancedByteBufferAccess, org.apache.hadoop.fs.HasFileDescriptor, PositionedReadable, Seekable, org.apache.hadoop.fs.statistics.IOStatisticsSource, StreamCapabilities

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

The Hdfs implementation of FSDataInputStream.

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, VECTOREDIO_BUFFERS_SLICED

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
void	clearReadStatistics()
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.
org.apache.hadoop.hdfs.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, getIOStatistics, getPos, hasCapability, maxReadSizeForVectorReads, minSeekForVectorReads, read, read, read, read, read, readFully, readFully, readFully, readVectored, 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.lang.Object

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

Constructor Detail

HdfsDataInputStream

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

HdfsDataInputStream

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

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 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()

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 org.apache.hadoop.hdfs.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()