Package org.apache.lucene.util

Class PForDeltaDocIdSet

java.lang.Object

org.apache.lucene.search.DocIdSet

org.apache.lucene.util.PForDeltaDocIdSet

public final class PForDeltaDocIdSet
extends DocIdSet

DocIdSet implementation based on pfor-delta encoding.

This implementation is inspired from LinkedIn's Kamikaze (http://data.linkedin.com/opensource/kamikaze) and Daniel Lemire's JavaFastPFOR (https://github.com/lemire/JavaFastPFOR).

On the contrary to the original PFOR paper, exceptions are encoded with FOR instead of Simple16.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PForDeltaDocIdSet.Builder	A builder for PForDeltaDocIdSet.

Method Summary

Modifier and Type	Method	Description
int	cardinality()	Return the number of documents in this DocIdSet in constant time.
boolean	isCacheable()	This method is a hint for CachingWrapperFilter, if this DocIdSet should be cached without copying it.
DocIdSetIterator	iterator()	Provides a DocIdSetIterator to access the set.
long	ramBytesUsed()	Return the memory usage of this instance.

Methods inherited from class org.apache.lucene.search.DocIdSet

bits

Methods inherited from class java.lang.Object

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

Method Details

isCacheable

public boolean isCacheable()

Description copied from class: DocIdSet

This method is a hint for CachingWrapperFilter, if this DocIdSet should be cached without copying it. The default is to return false. If you have an own DocIdSet implementation that does its iteration very effective and fast without doing disk I/O, override this method and return true.

Overrides:

isCacheable in class DocIdSet

iterator

public DocIdSetIterator iterator()

Description copied from class: DocIdSet

Provides a DocIdSetIterator to access the set. This implementation can return null if there are no docs that match.

Specified by:

iterator in class DocIdSet

cardinality

public int cardinality()

Return the number of documents in this DocIdSet in constant time.

ramBytesUsed

public long ramBytesUsed()

Return the memory usage of this instance.