org.terrier.structures
Class BlockDirectInvertedOutputStream

java.lang.Object
  org.terrier.structures.DirectInvertedOutputStream
      org.terrier.structures.BlockDirectInvertedOutputStream

All Implemented Interfaces:

java.io.Closeable

public class BlockDirectInvertedOutputStream
extends DirectInvertedOutputStream

Writes a block direct or block inverted index, when passed appropriate posting lists.

Since:

2.0

Author:

Craig Macdonald

Field Summary

Fields inherited from class org.terrier.structures.DirectInvertedOutputStream

logger, output

Constructor Summary

BlockDirectInvertedOutputStream(BitOut out)
Creates a new output stream, writing to the specified BitOut implementation.

BlockDirectInvertedOutputStream(java.lang.String filename)
Creates a new output stream, writing a BitOutputStream to the specified file.

Method Summary

java.lang.Class<? extends IterablePosting>	getPostingIteratorClass() Returns the IterablePosting class to use for reading structure written by this class
protected BitIndexPointer	writeNoFieldPostings(int[][] postings, int offset, int length, int firstId) Writes the given block postings to the bit file.
protected void	writePostingNotDocid(Posting _p) Hook method for writing out the remainder of the posting

Methods inherited from class org.terrier.structures.DirectInvertedOutputStream

close, getBitOffset, getBitOut, getByteOffset, getOffset, writePostings, writePostings, writePostings, writePostings, writePostings, writePostings

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockDirectInvertedOutputStream

public BlockDirectInvertedOutputStream(java.lang.String filename)
                                throws java.io.IOException

Creates a new output stream, writing a BitOutputStream to the specified file. The number of binary bits for fields must also be specified.

Parameters:

filename - Location of the file to write to

Throws:

java.io.IOException

BlockDirectInvertedOutputStream

public BlockDirectInvertedOutputStream(BitOut out)

Creates a new output stream, writing to the specified BitOut implementation. The number of binary bits for fields must also be specified.

Parameters:

out - BitOut implementation to write the file to

Method Detail

getPostingIteratorClass

public java.lang.Class<? extends IterablePosting> getPostingIteratorClass()

Description copied from class: DirectInvertedOutputStream

Returns the IterablePosting class to use for reading structure written by this class

Overrides:

getPostingIteratorClass in class DirectInvertedOutputStream

writeNoFieldPostings

protected BitIndexPointer writeNoFieldPostings(int[][] postings,
                                               int offset,
                                               int length,
                                               int firstId)
                                        throws java.io.IOException

Writes the given block postings to the bit file. This method assumes that field information is not provided.

Overrides:

writeNoFieldPostings in class DirectInvertedOutputStream

Parameters:

postings - the postings list to write.

firstId - the first identifier to write. This can be an id plus one, or the gap of the current id and the previous one.

offset - The location of the first posting to write out.

length - The number of postings to be written out.

Throws:

java.io.IOException - if an error occurs during writing to a file.

writePostingNotDocid

protected void writePostingNotDocid(Posting _p)
                             throws java.io.IOException

Description copied from class: DirectInvertedOutputStream

Hook method for writing out the remainder of the posting

Overrides:

writePostingNotDocid in class DirectInvertedOutputStream

Throws:

java.io.IOException