Package org.terrier.structures.indexing

Class BlockDocumentPostingList

java.lang.Object

org.terrier.structures.indexing.DocumentPostingList

org.terrier.structures.indexing.BlockDocumentPostingList

All Implemented Interfaces:

java.io.Serializable, org.apache.hadoop.io.Writable

public class BlockDocumentPostingList
extends DocumentPostingList

Represents the postings of one document, and saves block (term position) information. Uses HashMaps internally.

Properties:

• indexing.avg.unique.terms.per.doc - number of unique terms per doc on average, used to tune the initial size of the haashmaps used in this class.

See Also:

DocumentPostingList, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.terrier.structures.indexing.DocumentPostingList

DocumentPostingList.postingIterator

Field Summary

Fields

Modifier and Type	Field	Description
protected int	blockCount	number of blocks in this document.
protected gnu.trove.THashMap<java.lang.String,gnu.trove.TIntHashSet>	term_blocks	mapping term to blockids in this document

Fields inherited from class org.terrier.structures.indexing.DocumentPostingList

AVG_DOCUMENT_UNIQUE_TERMS, documentLength, occurrences

Constructor Summary

Constructors

Constructor	Description
BlockDocumentPostingList()	Instantiate a new block document posting list.

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all postings from this document
int[]	getBlocks(java.lang.String term)	return blocks
int[][]	getPostings(TermCodes termCodes)	returns the postings suitable to be written into the block direct index
void	insert(java.lang.String t, int blockId)	Insert a term into this document, occurs at given block id
protected IterablePosting	makePostingIterator(java.lang.String[] _terms, int[] termIds)
void	readFields(java.io.DataInput in)
void	write(java.io.DataOutput out)

Methods inherited from class org.terrier.structures.indexing.DocumentPostingList

forEachTerm, getDocumentLength, getDocumentStatistics, getFrequency, getNumberOfPointers, getPostings2, insert, insert, termSet

Methods inherited from class java.lang.Object

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

Field Detail

term_blocks

protected final gnu.trove.THashMap<java.lang.String,gnu.trove.TIntHashSet> term_blocks

mapping term to blockids in this document

blockCount

protected int blockCount

number of blocks in this document. usually equal to document length, but perhaps less

Constructor Detail

BlockDocumentPostingList

public BlockDocumentPostingList()

Instantiate a new block document posting list. Saves block information, but no fields

Method Detail

insert

public void insert(java.lang.String t,
                   int blockId)

Insert a term into this document, occurs at given block id

getBlocks

public int[] getBlocks(java.lang.String term)

return blocks

Parameters:

term -

Returns:

int[]

getPostings

public int[][] getPostings(TermCodes termCodes)

returns the postings suitable to be written into the block direct index

Overrides:

getPostings in class DocumentPostingList

makePostingIterator

protected IterablePosting makePostingIterator(java.lang.String[] _terms,
                                              int[] termIds)

Overrides:

makePostingIterator in class DocumentPostingList

clear

public void clear()

Description copied from class: DocumentPostingList

Removes all postings from this document

Overrides:

clear in class DocumentPostingList

readFields

public void readFields(java.io.DataInput in)
                throws java.io.IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Overrides:

readFields in class DocumentPostingList

Throws:

java.io.IOException

write

public void write(java.io.DataOutput out)
           throws java.io.IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Overrides:

write in class DocumentPostingList

Throws:

java.io.IOException