org.terrier.structures.indexing.singlepass
Class BlockPostingInRun

java.lang.Object
  extended by org.terrier.structures.indexing.singlepass.PostingInRun
      extended by org.terrier.structures.indexing.singlepass.SimplePostingInRun
          extended by org.terrier.structures.indexing.singlepass.BlockPostingInRun
Direct Known Subclasses:
BlockFieldPostingInRun

public class BlockPostingInRun
extends SimplePostingInRun

Class holding the information for a posting list read from a previously written run at disk. Used in the merging phase of the Single pass inversion method. This class knows how to append itself to a BitOut and it represents a posting with blocks information (tf, df, [docid, idf, blockFr [blockid]])

Author:
Roi Blanco

Nested Class Summary
protected  class BlockPostingInRun.BlockPIRPostingIterator
           
 
Nested classes/interfaces inherited from class org.terrier.structures.indexing.singlepass.SimplePostingInRun
SimplePostingInRun.PIRPostingIterator
 
Field Summary
 
Fields inherited from class org.terrier.structures.indexing.singlepass.PostingInRun
postingSource, term, termDf, termTF
 
Constructor Summary
BlockPostingInRun()
          Constructor for the class.
 
Method Summary
 int append(BitOut bos, int last, int runShift)
          Writes the document data of this posting to a BitOut It encodes the data with the right compression methods.
 IterablePosting getPostingIterator(int runShift)
          Returns an IterablePosting object for the postings in this run
 
Methods inherited from class org.terrier.structures.indexing.singlepass.PostingInRun
addToLexiconEntry, append, getDf, getLexiconEntry, getTerm, getTF, setDf, setPostingSource, setTerm, setTF
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BlockPostingInRun

public BlockPostingInRun()
Constructor for the class.

Method Detail

append

public int append(BitOut bos,
                  int last,
                  int runShift)
           throws IOException
Writes the document data of this posting to a BitOut It encodes the data with the right compression methods. The stream is written as d1, idf(d1), blockNo(d1), bid1, bid2, ..., d2 - d1, idf(d2), blockNo(d2), ... etc

Overrides:
append in class SimplePostingInRun
Parameters:
bos - BitOut to be written.
last - int representing the last document written in this posting.
runShift - amount of delta to apply to the first posting read.
Returns:
The last posting written.
Throws:
IOException

getPostingIterator

public IterablePosting getPostingIterator(int runShift)
                                   throws IOException
Description copied from class: PostingInRun
Returns an IterablePosting object for the postings in this run

Overrides:
getPostingIterator in class SimplePostingInRun
Throws:
IOException


Terrier 3.6. Copyright © 2004-2011 University of Glasgow