org.terrier.structures.indexing.singlepass.hadoop

Class HadoopRunPostingIterator

java.lang.Object

org.terrier.structures.indexing.singlepass.RunIterator

org.terrier.structures.indexing.singlepass.hadoop.HadoopRunPostingIterator

All Implemented Interfaces:

Closeable, AutoCloseable, Iterator<PostingInRun>

public class HadoopRunPostingIterator
extends RunIterator

This class allows the iteration of over a postings within a run within the Hadoop framwork.

Since:

2.2

Author:

Craig Macdonald

Field Summary

Fields

Modifier and Type	Field and Description
protected String	mapNo Map number
protected Iterator<MapEmittedPostingList>	postingIterator Runs To Be Merged
protected int	splitNo The Split that the current posting comes from
protected String	term Term that we're processing

Fields inherited from class org.terrier.structures.indexing.singlepass.RunIterator

flushNo, numberOfFields, posting, postingClass

Constructor Summary

Constructors

Constructor and Description
HadoopRunPostingIterator(Class<? extends PostingInRun> postingClass, int runNo, Iterator<MapEmittedPostingList> _postingiterator, String _term, int numFields) Constructs a new RunPostingIterator.

Method Summary

Methods

Modifier and Type	Method and Description
String	getMapNo() Returns the map that the current posting came from
int	getSplitNo()
boolean	hasNext() Move to the next posting
PostingInRun	next() Return the next PostingInRun

Methods inherited from class org.terrier.structures.indexing.singlepass.RunIterator

close, createPosting, current, getRunNo, remove

Methods inherited from class java.lang.Object

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

Field Detail

postingIterator

protected Iterator<MapEmittedPostingList> postingIterator

Runs To Be Merged

mapNo

protected String mapNo

Map number

term

protected String term

Term that we're processing

splitNo

protected int splitNo

The Split that the current posting comes from

Constructor Detail

HadoopRunPostingIterator

public HadoopRunPostingIterator(Class<? extends PostingInRun> postingClass,
                        int runNo,
                        Iterator<MapEmittedPostingList> _postingiterator,
                        String _term,
                        int numFields)
                         throws Exception

Constructs a new RunPostingIterator.

Parameters:

postingClass - is the name of the class to use to read the postings

runNo - is the number of the run

_postingiterator - is the iterator of reduce input data that we are going to loop through

_term - is the term that this iterator is operating on

Throws:

Exception

Method Detail

hasNext

public boolean hasNext()

Move to the next posting

Specified by:

hasNext in interface Iterator<PostingInRun>

Specified by:

hasNext in class RunIterator

next

public PostingInRun next()

Return the next PostingInRun

Specified by:

next in interface Iterator<PostingInRun>

Specified by:

next in class RunIterator

getMapNo

public String getMapNo()

Returns the map that the current posting came from

getSplitNo

public int getSplitNo()

Returns:

the splitNo