Package org.apache.lucene.util

Class FixedBitSet.FixedBitSetIterator

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

org.apache.lucene.util.FixedBitSet.FixedBitSetIterator

Enclosing class:

FixedBitSet

public static final class FixedBitSet.FixedBitSetIterator
extends DocIdSetIterator

A DocIdSetIterator which iterates over set bits in a FixedBitSet.

Field Summary

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

NO_MORE_DOCS

Constructor Summary

Constructors

Constructor	Description
FixedBitSetIterator(long[] bits, int numBits, int wordLength)	Creates an iterator over the given array of bits.
FixedBitSetIterator(FixedBitSet bits)	Creates an iterator over the given FixedBitSet.

Method Summary

Modifier and Type	Method	Description
int	advance(int target)	Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself.
long	cost()	Returns the estimated cost of this DocIdSetIterator.
int	docID()	Returns the following: -1 or DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
int	nextDoc()	Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set. NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

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

empty, slowAdvance

Methods inherited from class java.lang.Object

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

Constructor Detail

FixedBitSetIterator

public FixedBitSetIterator(FixedBitSet bits)

Creates an iterator over the given FixedBitSet.

FixedBitSetIterator

public FixedBitSetIterator(long[] bits,
                           int numBits,
                           int wordLength)

Creates an iterator over the given array of bits.

Method Detail

nextDoc

public int nextDoc()

Description copied from class: DocIdSetIterator

Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Specified by:

nextDoc in class DocIdSetIterator

docID

public int docID()

Description copied from class: DocIdSetIterator

Returns the following:

• -1 or DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
• DocIdSetIterator.NO_MORE_DOCS if the iterator has exhausted.
• Otherwise it should return the doc ID it is currently on.

Specified by:

docID in class DocIdSetIterator

cost

public long cost()

Description copied from class: DocIdSetIterator

Returns the estimated cost of this DocIdSetIterator.

This is generally an upper bound of the number of documents this iterator might match, but may be a rough heuristic, hardcoded value, or otherwise completely inaccurate.

Specified by:

cost in class DocIdSetIterator

advance

public int advance(int target)

Description copied from class: DocIdSetIterator

Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself. Exhausts the iterator and returns DocIdSetIterator.NO_MORE_DOCS if target is greater than the highest document number in the set.

The behavior of this method is undefined when called with target ≤ current, or after the iterator has exhausted. Both cases may result in unpredicted behavior.

When target > current it behaves as if written:

 int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
 

Some implementations are considerably more efficient than that.

NOTE: this method may be called with DocIdSetIterator.NO_MORE_DOCS for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

Specified by:

advance in class DocIdSetIterator