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

Class QuasiSuccinctIndexReader

java.lang.Object

it.unimi.di.big.mg4j.index.AbstractIndexReader

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

All Implemented Interfaces:

IndexReader, SafelyCloseable, Closeable, AutoCloseable

public class QuasiSuccinctIndexReader
extends AbstractIndexReader
implements IndexReader

An index reader for quasi-succinct indices.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	QuasiSuccinctIndexReader.AbstractQuasiSuccinctIndexIterator
protected static class	QuasiSuccinctIndexReader.CountReader
protected static class	QuasiSuccinctIndexReader.EliasFanoIndexIterator
protected static class	QuasiSuccinctIndexReader.EliasFanoPointerReader
protected static class	QuasiSuccinctIndexReader.LongWordBitReader
protected static class	QuasiSuccinctIndexReader.PointerReader
protected static class	QuasiSuccinctIndexReader.PositionReader
protected static class	QuasiSuccinctIndexReader.RankedIndexIterator
protected static class	QuasiSuccinctIndexReader.RankedPointerReader

Field Summary

Fields

Modifier and Type	Field	Description
protected LongBigList	countsList	A reference to the data for counts, or null of index has counts.
protected QuasiSuccinctIndexReader.EliasFanoIndexIterator	eliasFanoIndexIterator	An index iterator that can read Elias-Fano pointer lists.
protected QuasiSuccinctIndex	index	The index, cached.
protected LongBigList	pointersList	A reference to the data for pointers.
protected QuasiSuccinctIndexReader.LongWordBitReader	pointersLongWordBitReader	A longword bit reader used to check whether a posting list is ranked or not.
protected LongBigList	positionsList	A reference to the data for positions, or null of index has positions.
protected QuasiSuccinctIndexReader.LongWordBitReader	positionsLongWordBitReader	A longword bit reader used to retrieve values stored in the list of positions.
protected QuasiSuccinctIndexReader.RankedIndexIterator	rankedIndexIterator	An index iterator that can read ranked pointer lists.

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

closed

Constructor Summary

Constructors

Constructor	Description
QuasiSuccinctIndexReader(QuasiSuccinctIndex index)

Method Summary

Modifier and Type	Method	Description
IndexIterator	documents(long termNumber)	Returns a document iterator over the documents containing a term.
IndexIterator	documents(CharSequence term)	Returns an index iterator over the documents containing a term; the term is given explicitly.
IndexIterator	nextIterator()	Throws an UnsupportedOperationException.

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

close, finalize

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.io.Closeable

close

Field Detail

eliasFanoIndexIterator

protected final QuasiSuccinctIndexReader.EliasFanoIndexIterator eliasFanoIndexIterator

An index iterator that can read Elias-Fano pointer lists.

rankedIndexIterator

protected final QuasiSuccinctIndexReader.RankedIndexIterator rankedIndexIterator

An index iterator that can read ranked pointer lists.

index

protected final QuasiSuccinctIndex index

The index, cached.

pointersList

protected final LongBigList pointersList

A reference to the data for pointers.

countsList

protected final LongBigList countsList

A reference to the data for counts, or null of index has counts.

positionsList

protected final LongBigList positionsList

A reference to the data for positions, or null of index has positions.

pointersLongWordBitReader

protected final QuasiSuccinctIndexReader.LongWordBitReader pointersLongWordBitReader

A longword bit reader used to check whether a posting list is ranked or not.

positionsLongWordBitReader

protected final QuasiSuccinctIndexReader.LongWordBitReader positionsLongWordBitReader

A longword bit reader used to retrieve values stored in the list of positions.

Constructor Detail

QuasiSuccinctIndexReader

public QuasiSuccinctIndexReader(QuasiSuccinctIndex index)

Method Detail

documents

public IndexIterator documents(long termNumber)
                        throws IOException

Description copied from interface: IndexReader

Returns a document iterator over the documents containing a term.

Note that the index iterator returned by this method will return null on a call to term().

Note that it is always possible to call this method with argument 0, even if the underlying index does not provide random access.

Specified by:

documents in interface IndexReader

Parameters:

termNumber - the number of a term.

Throws:

IOException

documents

public IndexIterator documents(CharSequence term)
                        throws IOException

Description copied from interface: IndexReader

Returns an index iterator over the documents containing a term; the term is given explicitly.

Unless the term processor of the associated index is null, words coming from a query will have to be processed before being used with this method.

Note that the index iterator returned by this method will return term on a call to term().

Specified by:

documents in interface IndexReader

Parameters:

term - a term (the term will be downcased if the index is case insensitive).

Throws:

IOException

nextIterator

public IndexIterator nextIterator()
                           throws IOException

Description copied from class: AbstractIndexReader

Throws an UnsupportedOperationException.

Specified by:

nextIterator in interface IndexReader

Overrides:

nextIterator in class AbstractIndexReader

Returns:

the index iterator of the next term, or null if there are no more terms after the current one.

Throws:

IOException