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:
BinaryDocValues,BitSetIterator,ByteVectorValues,DisjunctionDISIApproximation,DocBaseBitSetIterator,FilteredDocIdSetIterator,FloatVectorValues,ImpactsDISI,IndexedDISI,MinDocIterator,NumericDocValues,PostingsEnum,QuantizedByteVectorValues,SortedDocValues,SortedNumericDocValues,SortedSetDocValues
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_DOCSis set to 2147483647 in order to be used as a sentinel object. Implementations of this class are expected to considerInteger.MAX_VALUEas an invalid value.
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Field Summary
Fields Modifier and Type Field Description static intNO_MORE_DOCSWhen 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 Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description abstract intadvance(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.static DocIdSetIteratorall(int maxDoc)ADocIdSetIteratorthat matches all documents up tomaxDoc - 1.abstract longcost()Returns the estimated cost of thisDocIdSetIterator.abstract intdocID()static DocIdSetIteratorempty()An emptyDocIdSetIteratorinstanceabstract intnextDoc()Advances to the next document in the set and returns the doc it is currently on, orNO_MORE_DOCSif 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.static DocIdSetIteratorrange(int minDoc, int maxDoc)ADocIdSetIteratorthat matches a range documents from minDocID (inclusive) to maxDocID (exclusive).protected intslowAdvance(int target)Slow (linear) implementation ofadvance(int)relying onnextDoc()to advance beyond the target position.
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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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empty
public static final DocIdSetIterator empty()
An emptyDocIdSetIteratorinstance
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all
public static final DocIdSetIterator all(int maxDoc)
ADocIdSetIteratorthat matches all documents up tomaxDoc - 1.
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range
public static final DocIdSetIterator range(int minDoc, int maxDoc)
ADocIdSetIteratorthat matches a range documents from minDocID (inclusive) to maxDocID (exclusive).
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docID
public abstract int docID()
Returns the following:-1ifnextDoc()oradvance(int)were not called yet.NO_MORE_DOCSif the iterator has exhausted.- Otherwise it should return the doc ID it is currently on.
- Since:
- 2.9
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nextDoc
public abstract int nextDoc() throws IOExceptionAdvances to the next document in the set and returns the doc it is currently on, orNO_MORE_DOCSif 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 IOExceptionAdvances 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 returnsNO_MORE_DOCSif 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 > currentit 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
NO_MORE_DOCSfor 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.- Throws:
IOException- Since:
- 2.9
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slowAdvance
protected final int slowAdvance(int target) throws IOExceptionSlow (linear) implementation ofadvance(int)relying onnextDoc()to advance beyond the target position.- Throws:
IOException
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cost
public abstract long cost()
Returns the estimated cost of thisDocIdSetIterator.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.
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