uk.ac.gla.terrier.structures
Class BlockLexiconOutputStream

java.lang.Object
  uk.ac.gla.terrier.structures.LexiconOutputStream
      uk.ac.gla.terrier.structures.BlockLexiconOutputStream

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

UTFBlockLexiconOutputStream

public class BlockLexiconOutputStream
extends LexiconOutputStream

An output stream for writing the lexicon to a file sequentially.

Version:

$Revision: 1.13 $

Author:

Douglas Johnson, Vassilis Plachouras

Constructor Summary

BlockLexiconOutputStream()
A default constructor.

BlockLexiconOutputStream(java.io.File file)
A constructor given the file.

BlockLexiconOutputStream(java.lang.String filename)
A constructor given the filename.

Method Summary

void	setBF(int blockFrequency) Sets the block frequency for the given term
int	writeNextEntry(byte[] term, int termId, int documentFrequency, int blockFrequency, int termFrequency, long endOffset, byte endBitOffset) Write a lexicon entry.
int	writeNextEntry(java.lang.String term, int termId, int documentFrequency, int termFrequency, int blockFrequency, long endOffset, byte endBitOffset) Write a lexicon entry.

Methods inherited from class uk.ac.gla.terrier.structures.LexiconOutputStream

close, getNumberOfPointersWritten, getNumberOfTermsWritten, getNumberOfTokensWritten, setEndBitOffset, setEndOffset, setNt, setTerm, setTermId, setTF, writeNextEntry, writeNextEntry

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockLexiconOutputStream

public BlockLexiconOutputStream()

A default constructor.

BlockLexiconOutputStream

public BlockLexiconOutputStream(java.lang.String filename)

A constructor given the filename.

Parameters:

filename - java.lang.String the name of the lexicon file.

BlockLexiconOutputStream

public BlockLexiconOutputStream(java.io.File file)

A constructor given the file.

Parameters:

file - java.io.File the lexicon file.

Method Detail

writeNextEntry

public int writeNextEntry(java.lang.String term,
                          int termId,
                          int documentFrequency,
                          int termFrequency,
                          int blockFrequency,
                          long endOffset,
                          byte endBitOffset)
                   throws java.io.IOException

Write a lexicon entry.

Parameters:

term - the string representation of the term

termId - the terms integer identifier

documentFrequency - the term's document frequency in the collection

termFrequency - the term's frequency in the collection

endOffset - the term's ending byte offset in the inverted file

endBitOffset - the term's ending byte bit-offset in the inverted file

Returns:

the number of bytes written if there is no error, otherwise returns -1 in case of EOF

Throws:

java.io.IOException - if an I/O error occurs

writeNextEntry

public int writeNextEntry(byte[] term,
                          int termId,
                          int documentFrequency,
                          int blockFrequency,
                          int termFrequency,
                          long endOffset,
                          byte endBitOffset)
                   throws java.io.IOException

Write a lexicon entry.

Parameters:

term - the byte array representation of the term

termId - the terms integer identifier

documentFrequency - the term's document frequency in the collection

termFrequency - the term's frequency in the collection

endOffset - the term's ending byte offset in the inverted file

endBitOffset - the term's ending byte bit-offset in the inverted file

Returns:

the number of bytes written if there is no error, otherwise returns -1 in case of EOF

Throws:

java.io.IOException - if an I/O error occurs

setBF

public void setBF(int blockFrequency)

Sets the block frequency for the given term

Parameters:

blockFrequency - The new block frequency