org.apache.hadoop.io

Class ArrayFile.Reader

java.lang.Object

org.apache.hadoop.io.MapFile.Reader

org.apache.hadoop.io.ArrayFile.Reader

All Implemented Interfaces:

Closeable, AutoCloseable

Enclosing class:

ArrayFile

public static class ArrayFile.Reader
extends MapFile.Reader

Provide access to an existing array file.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.io.MapFile.Reader

MapFile.Reader.Option

Constructor Summary

Constructors

Constructor and Description
Reader(FileSystem fs, String file, Configuration conf) Construct an array reader for the named file.

Method Summary

Modifier and Type	Method and Description
Writable	get(long n, Writable value) Return the nth value in the file.
long	key() Returns the key associated with the most recent call to seek(long), next(Writable), or get(long,Writable).
Writable	next(Writable value) Read and return the next value in the file.
void	seek(long n) Positions the reader before its nth value.

Methods inherited from class org.apache.hadoop.io.MapFile.Reader

close, comparator, createDataFileReader, finalKey, get, getClosest, getClosest, getKeyClass, getValueClass, midKey, next, open, reset, seek

Methods inherited from class java.lang.Object

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

Constructor Detail

Reader

public Reader(FileSystem fs,
              String file,
              Configuration conf)
       throws IOException

Construct an array reader for the named file.

Parameters:

fs - FileSystem.

file - file.

conf - configuration.

Throws:

IOException - raised on errors performing I/O.

Method Detail

seek

public void seek(long n)
          throws IOException

Positions the reader before its nth value.

Parameters:

n - n key.

Throws:

IOException - raised on errors performing I/O.

next

public Writable next(Writable value)
              throws IOException

Read and return the next value in the file.

Parameters:

value - value.

Returns:

Writable.

Throws:

IOException - raised on errors performing I/O.

key

public long key()
         throws IOException

Returns the key associated with the most recent call to seek(long), next(Writable), or get(long,Writable).

Returns:

key key.

Throws:

IOException - raised on errors performing I/O.

get

public Writable get(long n,
                    Writable value)
             throws IOException

Return the nth value in the file.

Parameters:

n - n key.

value - value.

Returns:

writable.

Throws:

IOException - raised on errors performing I/O.