org.terrier.structures.indexing.singlepass

Class Posting

java.lang.Object

org.terrier.structures.indexing.singlepass.Posting

Direct Known Subclasses:

BlockPosting, FieldPosting

public class Posting
extends Object

Class representing a simple posting list in memory. It keeps the information for TF, Nt, maxtf, and the sequence [doc, tf]

Author:

Roi Blanco

Field Summary

Fields

Modifier and Type	Field and Description
protected MemorySBOS	docIds The compressed in-memory object holding the sequence doc_id, idf
protected int	lastInt Last document inserted in the posting
protected int	maxtf
protected int	Nt The document frequency
protected int	TF The term frequency

Constructor Summary

Constructors

Constructor and Description
Posting()

Method Summary

Modifier and Type	Method and Description
int	getDocF()
MemorySBOS	getDocs()
int	getMaxtf()
int	getSize() Returns the size of the underlying buffer representing this posting set.
int	getTF()
int	insert(int doc, int freq) Inserts a new document in the posting list.
void	setDocF(int docF) Set the document frequency the number of documents this term occurs in.
void	setDocs(MemorySBOS docs) Sets the document data compressed object.
void	setTF(int tf) Sets the term frequency in the run.
int	writeFirstDoc(int docId, int freq) Writes the first document in the posting list.

Methods inherited from class java.lang.Object

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

Field Detail

TF

protected int TF

The term frequency

Nt

protected int Nt

The document frequency

maxtf

protected int maxtf

docIds

protected MemorySBOS docIds

The compressed in-memory object holding the sequence doc_id, idf

lastInt

protected int lastInt

Last document inserted in the posting

Constructor Detail

Posting

public Posting()

Method Detail

writeFirstDoc

public int writeFirstDoc(int docId,
                         int freq)
                  throws IOException

Writes the first document in the posting list.

Parameters:

docId - the document identifier.

freq - the frequency of the term in the document.

Returns:

the number of bytes consumed in the buffer

Throws:

IOException - if an I/O error ocurrs.

insert

public int insert(int doc,
                  int freq)
           throws IOException

Inserts a new document in the posting list. Document insertions must be done in order.

Parameters:

doc - the document identifier.

freq - the frequency of the term in the document.

Returns:

the number of bytes consumed in the buffer

Throws:

IOException - if and I/O error occurs.

getMaxtf

public int getMaxtf()

Returns:

the max term frequency of the term in any document in the run

getTF

public int getTF()

Returns:

the term frequency of the term in the run

getDocs

public MemorySBOS getDocs()

Returns:

the document data compressed object.

setTF

public void setTF(int tf)

Sets the term frequency in the run.

Parameters:

tf - the term frequency.

setDocs

public void setDocs(MemorySBOS docs)

Sets the document data compressed object.

Parameters:

docs -

getDocF

public int getDocF()

Returns:

the document frequency - the number of documents this term occurs in

setDocF

public void setDocF(int docF)

Set the document frequency the number of documents this term occurs in.

Parameters:

docF - the document frequency.

getSize

public int getSize()

Returns the size of the underlying buffer representing this posting set.