Package org.apache.lucene.search
Class DocIdSetIterator
- java.lang.Object
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- org.apache.lucene.search.DocIdSetIterator
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- Direct Known Subclasses:
FilteredDocIdSetIterator
,OpenBitSetIterator
,Scorer
public abstract class DocIdSetIterator extends Object
This abstract class defines methods to iterate over a set of non-decreasing doc ids. Note that this class assumes it iterates on doc Ids, and thereforeNO_MORE_DOCS
is set to 2147483647 in order to be used as a sentinel object. Implementations of this class are expected to considerInteger.MAX_VALUE
as an invalid value.
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Field Summary
Fields Modifier and Type Field Description static int
NO_MORE_DOCS
When returned bynextDoc()
,advance(int)
anddocID()
it means there are no more docs in the iterator.
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Constructor Summary
Constructors Constructor Description DocIdSetIterator()
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description abstract int
advance(int target)
Advances to the first beyond (see NOTE below) the current whose document number is greater than or equal to target.abstract int
docID()
abstract int
nextDoc()
Advances to the next document in the set and returns the doc it is currently on, orNO_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.
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Field Detail
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NO_MORE_DOCS
public static final int NO_MORE_DOCS
When returned bynextDoc()
,advance(int)
anddocID()
it means there are no more docs in the iterator.- See Also:
- Constant Field Values
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Method Detail
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docID
public abstract int docID()
Returns the following:- -1 or
NO_MORE_DOCS
ifnextDoc()
oradvance(int)
were not called yet. NO_MORE_DOCS
if the iterator has exhausted.- Otherwise it should return the doc ID it is currently on.
- Since:
- 2.9
- -1 or
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nextDoc
public abstract int nextDoc() throws IOException
Advances to the next document in the set and returns the doc it is currently on, orNO_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.- Throws:
IOException
- Since:
- 2.9
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advance
public abstract int advance(int target) throws IOException
Advances to the first beyond (see NOTE below) the current whose document number is greater than or equal to target. Returns the current document number orNO_MORE_DOCS
if there are no more docs in the set.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: when
target ≤ current
implementations may opt not to advance beyond their currentdocID()
.NOTE: this method may be called with
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.NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
- Throws:
IOException
- Since:
- 2.9
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