org.apache.lucene.util

Class BitDocIdSet

java.lang.Object

org.apache.lucene.search.DocIdSet

org.apache.lucene.util.BitDocIdSet

All Implemented Interfaces:

Accountable

public class BitDocIdSet
extends DocIdSet

Implementation of the DocIdSet interface on top of a BitSet.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BitDocIdSet.Builder A builder of DocIdSets that supports random access.

Field Summary

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

EMPTY

Constructor Summary

Constructors

Constructor and Description
BitDocIdSet(BitSet set) Same as BitDocIdSet(BitSet, long) but uses the set's approximate cardinality as a cost.
BitDocIdSet(BitSet set, long cost) Wrap the given FixedBitSet as a DocIdSet.

Method Summary

Methods

Modifier and Type	Method and Description
BitSet	bits() Optionally provides a Bits interface for random access to matching documents.
boolean	isCacheable() This DocIdSet implementation is cacheable.
DocIdSetIterator	iterator() Provides a DocIdSetIterator to access the set.
long	ramBytesUsed() Return the memory usage of this object in bytes.
String	toString()

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

getChildResources

Methods inherited from class java.lang.Object

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

Constructor Detail

BitDocIdSet

public BitDocIdSet(BitSet set,
           long cost)

Wrap the given FixedBitSet as a DocIdSet. The provided FixedBitSet should not be modified after having wrapped as a DocIdSet.

BitDocIdSet

public BitDocIdSet(BitSet set)

Same as BitDocIdSet(BitSet, long) but uses the set's approximate cardinality as a cost.

Method Detail

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

bits

public BitSet bits()

Description copied from class: DocIdSet

Optionally provides a Bits interface for random access to matching documents.

Overrides:

bits in class DocIdSet

Returns:

null, if this DocIdSet does not support random access. In contrast to DocIdSet.iterator(), a return value of null does not imply that no documents match the filter! The default implementation does not provide random access, so you only need to implement this method if your DocIdSet can guarantee random access to every docid in O(1) time without external disk access (as Bits interface cannot throw IOException). This is generally true for bit sets like FixedBitSet, which return itself if they are used as DocIdSet.

isCacheable

public boolean isCacheable()

This DocIdSet implementation is cacheable.

Overrides:

isCacheable in class DocIdSet

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

toString

public String toString()

Overrides:

toString in class Object