Package org.apache.lucene.search.spans
Class FilterSpans
- java.lang.Object
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- org.apache.lucene.search.DocIdSetIterator
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- org.apache.lucene.search.spans.Spans
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- org.apache.lucene.search.spans.FilterSpans
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public abstract class FilterSpans extends Spans
ASpans
implementation wrapping another spans instance, allowing to filter spans matches easily by implementingaccept(org.apache.lucene.search.spans.Spans)
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
FilterSpans.AcceptStatus
Status returned fromaccept(Spans)
that indicates whether a candidate match should be accepted, rejected, or rejected and move on to the next document.
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Field Summary
Fields Modifier and Type Field Description protected Spans
in
The wrapped spans instance.-
Fields inherited from class org.apache.lucene.search.spans.Spans
NO_MORE_POSITIONS
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Fields inherited from class org.apache.lucene.search.DocIdSetIterator
NO_MORE_DOCS
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Constructor Summary
Constructors Modifier Constructor Description protected
FilterSpans(Spans in)
Wrap the givenSpans
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract FilterSpans.AcceptStatus
accept(Spans candidate)
Returns YES if the candidate should be an accepted match, NO if it should not, and NO_MORE_IN_CURRENT_DOC if iteration should move on to the next document.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.TwoPhaseIterator
asTwoPhaseIterator()
Optional method: Return aTwoPhaseIterator
view of thisScorer
.void
collect(SpanCollector collector)
Collect postings data from the leaves of the current Spans.long
cost()
Returns the estimated cost of thisDocIdSetIterator
.int
docID()
Returns the following:-1
ifDocIdSetIterator.nextDoc()
orDocIdSetIterator.advance(int)
were not called yet.int
endPosition()
Returns the end position for the current start position, or -1 whenSpans.nextStartPosition()
was not yet called on the current doc.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.int
nextStartPosition()
Returns the next start position for the current doc.float
positionsCost()
Return an estimation of the cost of using the positions of thisSpans
for any single document, but only afterSpans.asTwoPhaseIterator()
returnednull
.int
startPosition()
Returns the start position in the current doc, or -1 whenSpans.nextStartPosition()
was not yet called on the current doc.String
toString()
int
width()
Return the width of the match, which is typically used to compute theslop factor
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Methods inherited from class org.apache.lucene.search.spans.Spans
doCurrentSpans, doStartCurrentDoc
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Methods inherited from class org.apache.lucene.search.DocIdSetIterator
all, empty, range, slowAdvance
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Field Detail
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in
protected final Spans in
The wrapped spans instance.
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Method Detail
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accept
protected abstract FilterSpans.AcceptStatus accept(Spans candidate) throws IOException
Returns YES if the candidate should be an accepted match, NO if it should not, and NO_MORE_IN_CURRENT_DOC if iteration should move on to the next document.- Throws:
IOException
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nextDoc
public final int nextDoc() throws 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:
IOException
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advance
public final int advance(int target) throws 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:
IOException
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docID
public final int docID()
Description copied from class:DocIdSetIterator
Returns the following:-1
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
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nextStartPosition
public final int nextStartPosition() throws IOException
Description copied from class:Spans
Returns the next start position for the current doc. There is always at least one start/end position per doc. After the last start/end position at the current doc this returnsSpans.NO_MORE_POSITIONS
.- Specified by:
nextStartPosition
in classSpans
- Throws:
IOException
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startPosition
public final int startPosition()
Description copied from class:Spans
Returns the start position in the current doc, or -1 whenSpans.nextStartPosition()
was not yet called on the current doc. After the last start/end position at the current doc this returnsSpans.NO_MORE_POSITIONS
.- Specified by:
startPosition
in classSpans
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endPosition
public final int endPosition()
Description copied from class:Spans
Returns the end position for the current start position, or -1 whenSpans.nextStartPosition()
was not yet called on the current doc. After the last start/end position at the current doc this returnsSpans.NO_MORE_POSITIONS
.- Specified by:
endPosition
in classSpans
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width
public int width()
Description copied from class:Spans
Return the width of the match, which is typically used to compute theslop factor
. It is only legal to call this method when the iterator is on a valid doc ID and positioned. The return value must be positive, and lower values means that the match is better.
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collect
public void collect(SpanCollector collector) throws IOException
Description copied from class:Spans
Collect postings data from the leaves of the current Spans. This method should only be called afterSpans.nextStartPosition()
, and beforeSpans.NO_MORE_POSITIONS
has been reached.- Specified by:
collect
in classSpans
- Parameters:
collector
- a SpanCollector- Throws:
IOException
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cost
public final 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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asTwoPhaseIterator
public final TwoPhaseIterator asTwoPhaseIterator()
Description copied from class:Spans
Optional method: Return aTwoPhaseIterator
view of thisScorer
. A return value ofnull
indicates that two-phase iteration is not supported.- Overrides:
asTwoPhaseIterator
in classSpans
- See Also:
Scorer.twoPhaseIterator()
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positionsCost
public float positionsCost()
Description copied from class:Spans
Return an estimation of the cost of using the positions of thisSpans
for any single document, but only afterSpans.asTwoPhaseIterator()
returnednull
. Otherwise this method should not be called. The returned value is independent of the current document.- Specified by:
positionsCost
in classSpans
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