Package org.apache.lucene.search
Class FilteredDocIdSetIterator
- java.lang.Object
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- org.apache.lucene.search.DocIdSetIterator
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- org.apache.lucene.search.FilteredDocIdSetIterator
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public abstract class FilteredDocIdSetIterator extends DocIdSetIterator
Abstract decorator class of a DocIdSetIterator implementation that provides on-demand filter/validation mechanism on an underlying DocIdSetIterator. SeeFilteredDocIdSet
.
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Field Summary
Fields Modifier and Type Field Description protected DocIdSetIterator
_innerIter
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Fields inherited from class org.apache.lucene.search.DocIdSetIterator
NO_MORE_DOCS
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Constructor Summary
Constructors Constructor Description FilteredDocIdSetIterator(DocIdSetIterator innerIter)
Constructor.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods 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 thisDocIdSetIterator
.int
docID()
Returns the following: -1 orDocIdSetIterator.NO_MORE_DOCS
ifDocIdSetIterator.nextDoc()
orDocIdSetIterator.advance(int)
were not called yet.protected abstract boolean
match(int doc)
Validation method to determine whether a docid should be in the result set.int
nextDoc()
Advances to the next document in the set and returns the doc it is currently on, orDocIdSetIterator.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
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Field Detail
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_innerIter
protected DocIdSetIterator _innerIter
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Constructor Detail
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FilteredDocIdSetIterator
public FilteredDocIdSetIterator(DocIdSetIterator innerIter)
Constructor.- Parameters:
innerIter
- Underlying DocIdSetIterator.
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Method Detail
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match
protected abstract boolean match(int doc)
Validation method to determine whether a docid should be in the result set.- Parameters:
doc
- docid to be tested- Returns:
- true if input docid should be in the result set, false otherwise.
- See Also:
FilteredDocIdSetIterator(DocIdSetIterator)
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docID
public int docID()
Description copied from class:DocIdSetIterator
Returns the following:- -1 or
DocIdSetIterator.NO_MORE_DOCS
ifDocIdSetIterator.nextDoc()
orDocIdSetIterator.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 classDocIdSetIterator
- -1 or
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nextDoc
public int nextDoc() throws java.io.IOException
Description copied from class:DocIdSetIterator
Advances to the next document in the set and returns the doc it is currently on, orDocIdSetIterator.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 classDocIdSetIterator
- Throws:
java.io.IOException
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advance
public int advance(int target) throws java.io.IOException
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 returnsDocIdSetIterator.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 classDocIdSetIterator
- Throws:
java.io.IOException
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cost
public long cost()
Description copied from class:DocIdSetIterator
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.
- Specified by:
cost
in classDocIdSetIterator
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