org.terrier.structures.integer

Class IntegerCodingPostingIndexInputStream

java.lang.Object

org.terrier.structures.integer.IntegerCodingPostingIndexInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, Iterator<IterablePosting>, PostingIndexInputStream, Skipable

public class IntegerCodingPostingIndexInputStream
extends Object
implements PostingIndexInputStream, Skipable

Input stream for an integer coding posting index.

Since:

4.0

Author:

Craig Macdonald, Matteo Catena

Field Summary

Fields

Modifier and Type	Field and Description
protected IntegerCodec	blocksCodec
protected int	chunkSize
protected int	currentEntryCount
protected byte	currentFile
protected BitIndexPointer	currentPointer
protected DocumentIndex	documentIndex
protected int	entriesSkipped
protected IntegerCodec	fieldsCodec
protected int	fieldsCount
protected ByteIn	file The compressed file containing the terms.
protected byte	fileCount
protected int	hasBlocks
protected IntegerCodec	idsCodec
protected IndexOnDisk	index
protected static org.apache.log4j.Logger	logger
protected Iterator<? extends BitIndexPointer>	pointerList the lexicon input stream providing the offsets
protected String	structureName
protected IntegerCodec	tfsCodec

Constructor Summary

Constructors

Constructor and Description
IntegerCodingPostingIndexInputStream(IndexOnDisk _index, String _structureName, Iterator<? extends BitIndexPointer> _pointerList) Constructs an instance

Method Summary

Methods

Modifier and Type	Method and Description
protected BitIndexPointer	_next()
void	close()
Pointer	getCurrentPointer() Returns the pointer associated with the current postings being accessed
protected DocumentIndex	getDocumentIndex(BitIndexPointer pointer)
int	getEntriesSkipped() Returns the number of entries that were skipped during a call to the next().
static String	getFilename(IndexOnDisk _index, String structureName, byte fileCount, byte fileId) Returns filename
static String	getFilename(String path, String prefix, String structureName, byte fileCount, byte fileId) Return filename
IterablePosting	getNextPostings() Return the next IterablePosting object, or null if none defined.
int	getNumberOfCurrentPostings() Returns the number of postings in the current IterablePosting object
BitFilePosition	getPos() Get the file position
boolean	hasNext()
protected IterablePosting	loadPostingIterator(BitIndexPointer pointer)
IterablePosting	next()
void	print() Print a list of the postings to standard out
void	remove() Not supported
void	skip(int numEntries) Skip forward the specified number of entries.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final org.apache.log4j.Logger logger

pointerList

protected final Iterator<? extends BitIndexPointer> pointerList

the lexicon input stream providing the offsets

file

protected ByteIn file

The compressed file containing the terms.

currentEntryCount

protected int currentEntryCount

currentPointer

protected BitIndexPointer currentPointer

entriesSkipped

protected int entriesSkipped

fileCount

protected byte fileCount

currentFile

protected byte currentFile

index

protected IndexOnDisk index

documentIndex

protected DocumentIndex documentIndex

structureName

protected String structureName

fieldsCount

protected int fieldsCount

hasBlocks

protected int hasBlocks

chunkSize

protected int chunkSize

idsCodec

protected IntegerCodec idsCodec

tfsCodec

protected IntegerCodec tfsCodec

fieldsCodec

protected IntegerCodec fieldsCodec

blocksCodec

protected IntegerCodec blocksCodec

Constructor Detail

IntegerCodingPostingIndexInputStream

public IntegerCodingPostingIndexInputStream(IndexOnDisk _index,
                                    String _structureName,
                                    Iterator<? extends BitIndexPointer> _pointerList)
                                     throws IOException

Constructs an instance

Parameters:

_index -

_structureName -

_pointerList -

Throws:

IOException

Method Detail

getFilename

public static String getFilename(String path,
                 String prefix,
                 String structureName,
                 byte fileCount,
                 byte fileId)

Return filename

Parameters:

path -

prefix -

structureName -

fileCount -

fileId -

Returns:

filename

getFilename

public static String getFilename(IndexOnDisk _index,
                 String structureName,
                 byte fileCount,
                 byte fileId)

Returns filename

Parameters:

_index -

structureName -

fileCount -

fileId -

Returns:

filename

getPos

public BitFilePosition getPos()

Get the file position

skip

public void skip(int numEntries)
          throws IOException

Skip forward the specified number of entries. Should be followed by a next() call.

Specified by:

skip in interface Skipable

Parameters:

numEntries - number of entries to skip

Throws:

IOException - if an IO problem occurs.

getNumberOfCurrentPostings

public int getNumberOfCurrentPostings()

Returns the number of postings in the current IterablePosting object

Specified by:

getNumberOfCurrentPostings in interface PostingIndexInputStream

getNextPostings

public IterablePosting getNextPostings()
                                throws IOException

Return the next IterablePosting object, or null if none defined. Use this method instead of hasNext() and next().

Specified by:

getNextPostings in interface PostingIndexInputStream

Returns:

IterablePosting postings for next object

Throws:

IOException - if an I/O problem occurs.

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<IterablePosting>

_next

protected BitIndexPointer _next()

next

public IterablePosting next()

Specified by:

next in interface Iterator<IterablePosting>

getEntriesSkipped

public int getEntriesSkipped()

Returns the number of entries that were skipped during a call to the next().

Specified by:

getEntriesSkipped in interface PostingIndexInputStream

Returns:

int the number of entries skipped.

loadPostingIterator

protected IterablePosting loadPostingIterator(BitIndexPointer pointer)
                                       throws IOException

Throws:

IOException

getDocumentIndex

protected DocumentIndex getDocumentIndex(BitIndexPointer pointer)

print

public void print()

Print a list of the postings to standard out

Specified by:

print in interface PostingIndexInputStream

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

remove

public void remove()

Not supported

Specified by:

remove in interface Iterator<IterablePosting>

getCurrentPointer

public Pointer getCurrentPointer()

Returns the pointer associated with the current postings being accessed

Specified by:

getCurrentPointer in interface PostingIndexInputStream