Package it.unimi.di.big.mg4j.index

Class QuasiSuccinctIndexReader.EliasFanoIndexIterator

java.lang.Object

it.unimi.di.big.mg4j.index.AbstractIndexIterator

it.unimi.di.big.mg4j.index.QuasiSuccinctIndexReader.AbstractQuasiSuccinctIndexIterator

it.unimi.di.big.mg4j.index.QuasiSuccinctIndexReader.EliasFanoIndexIterator

All Implemented Interfaces:

IndexIterator, DocumentIterator

Enclosing class:

QuasiSuccinctIndexReader

protected static final class QuasiSuccinctIndexReader.EliasFanoIndexIterator
extends QuasiSuccinctIndexReader.AbstractQuasiSuccinctIndexIterator

Field Summary

Fields

Modifier and Type	Field	Description
protected QuasiSuccinctIndexReader.EliasFanoPointerReader	pointers	The pointer reader for the current term.

Fields inherited from class it.unimi.di.big.mg4j.index.QuasiSuccinctIndexReader.AbstractQuasiSuccinctIndexIterator

count, counts, countsList, currentDocument, currentTerm, frequency, hasCounts, hasPositions, index, indexReader, nextPosition, numberOfDocuments, occurrency, pointersList, positions, positionsList

Fields inherited from class it.unimi.di.big.mg4j.index.AbstractIndexIterator

id, term, weight

Fields inherited from interface it.unimi.di.big.mg4j.search.DocumentIterator

END_OF_LIST

Fields inherited from interface it.unimi.di.big.mg4j.index.IndexIterator

END_OF_POSITIONS

Constructor Summary

Constructors

Constructor	Description
EliasFanoIndexIterator(QuasiSuccinctIndexReader indexReader)

Method Summary

Modifier and Type	Method	Description
int	count()	Returns the count, that is, the number of occurrences of the term in the current document.
boolean	mayHaveNext()	Returns whether there may be a next document, possibly with false positives.
long	nextDocument()	Returns the next document provided by this document iterator, or DocumentIterator.END_OF_LIST if no more documents are available.
protected boolean	position(long termNumber, long frequency, long occurrency)
long	skipTo(long n)	Skips all documents smaller than n.

Methods inherited from class it.unimi.di.big.mg4j.index.QuasiSuccinctIndexReader.AbstractQuasiSuccinctIndexIterator

dispose, document, frequency, index, indices, intervalIterator, intervalIterator, intervalIterators, nextPosition, payload, termNumber, toString

Methods inherited from class it.unimi.di.big.mg4j.index.AbstractIndexIterator

accept, acceptOnTruePaths, id, id, term, term, weight, weight

Methods inherited from class java.lang.Object

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

Field Detail

pointers

protected QuasiSuccinctIndexReader.EliasFanoPointerReader pointers

The pointer reader for the current term.

Constructor Detail

EliasFanoIndexIterator

public EliasFanoIndexIterator(QuasiSuccinctIndexReader indexReader)

Method Detail

position

protected boolean position(long termNumber,
                           long frequency,
                           long occurrency)

nextDocument

public long nextDocument()
                  throws IOException

Description copied from interface: DocumentIterator

Returns the next document provided by this document iterator, or DocumentIterator.END_OF_LIST if no more documents are available.

Returns:

the next document, or DocumentIterator.END_OF_LIST if no more documents are available.

Throws:

IOException

skipTo

public long skipTo(long n)
            throws IOException

Description copied from interface: DocumentIterator

Skips all documents smaller than n.

Define the current document k associated with this document iterator as follows:

• -1, if DocumentIterator.nextDocument() and this method have never been called;
• DocumentIterator.END_OF_LIST, if a call to this method or to DocumentIterator.nextDocument() returned DocumentIterator.END_OF_LIST;
• the last value returned by a call to DocumentIterator.nextDocument() or this method, otherwise.

If k is larger than or equal to n, then this method does nothing and returns k. Otherwise, a call to this method is equivalent to

 while( ( k = nextDocument() ) < n );
 return k;
 

Thus, when a result k ≠ DocumentIterator.END_OF_LIST is returned, the state of this iterator will be exactly the same as after a call to DocumentIterator.nextDocument() that returned k. In particular, the first document larger than or equal to n (when returned by this method) will not be returned by the next call to DocumentIterator.nextDocument().

Parameters:

n - a document pointer.

Returns:

a document pointer larger than or equal to n if available, DocumentIterator.END_OF_LIST otherwise.

Throws:

IOException

mayHaveNext

public boolean mayHaveNext()

Description copied from interface: DocumentIterator

Returns whether there may be a next document, possibly with false positives.

Returns:

true there may be a next document; false if certainly there is no next document.

count

public int count()
          throws IOException

Description copied from interface: IndexIterator

Returns the count, that is, the number of occurrences of the term in the current document.

Returns:

the count (number of occurrences) of the term in the current document.

Throws:

IOException