org.apache.hadoop.mapred
Class IFileInputStream

java.lang.Object
  java.io.InputStream
      org.apache.hadoop.mapred.IFileInputStream

All Implemented Interfaces:

Closeable

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class IFileInputStream
extends InputStream

A checksum input stream, used for IFiles. Used to validate the checksum of files created by IFileOutputStream.

Field Summary

static org.apache.commons.logging.Log

LOG

Constructor Summary

IFileInputStream(InputStream in, long len, org.apache.hadoop.conf.Configuration conf)
Create a checksum input stream that reads

Method Summary

void	close() Close the input stream.
byte[]	getChecksum()
long	getPosition()
long	getSize()
int	read()
int	read(byte[] b, int off, int len) Read bytes from the stream.
int	readWithChecksum(byte[] b, int off, int len) Read bytes from the stream.
long	skip(long n)

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, reset

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

Constructor Detail

IFileInputStream

public IFileInputStream(InputStream in,
                        long len,
                        org.apache.hadoop.conf.Configuration conf)

Create a checksum input stream that reads

Parameters:

in - The input stream to be verified for checksum.

len - The length of the input stream including checksum bytes.

Method Detail

close

public void close()
           throws IOException

Close the input stream. Note that we need to read to the end of the stream to validate the checksum.

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

getPosition

public long getPosition()

getSize

public long getSize()

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Read bytes from the stream. At EOF, checksum is validated, but the checksum bytes are not passed back in the buffer.

Overrides:

read in class InputStream

Throws:

IOException

readWithChecksum

public int readWithChecksum(byte[] b,
                            int off,
                            int len)
                     throws IOException

Read bytes from the stream. At EOF, checksum is validated and sent back as the last four bytes of the buffer. The caller should handle these bytes appropriately

Throws:

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

getChecksum

public byte[] getChecksum()