Package org.apache.lucene.queries.spans

Class FilterSpans

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

org.apache.lucene.queries.spans.Spans

org.apache.lucene.queries.spans.FilterSpans

public abstract class FilterSpans
extends Spans

A Spans implementation wrapping another spans instance, allowing to filter spans matches easily by implementing accept(org.apache.lucene.queries.spans.Spans)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FilterSpans.AcceptStatus	Status returned from accept(Spans) that indicates whether a candidate match should be accepted, rejected, or rejected and move on to the next document.

Field Summary

Fields

Modifier and Type	Field	Description
protected Spans	in	The wrapped spans instance.

Fields inherited from class org.apache.lucene.queries.spans.Spans

NO_MORE_POSITIONS

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

NO_MORE_DOCS

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	FilterSpans(Spans in)	Wrap the given Spans.

Method Summary

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)
TwoPhaseIterator	asTwoPhaseIterator()	Optional method: Return a TwoPhaseIterator view of this Scorer.
void	collect(SpanCollector collector)	Collect postings data from the leaves of the current Spans.
long	cost()
int	docID()
int	endPosition()	Returns the end position for the current start position, or -1 when Spans.nextStartPosition() was not yet called on the current doc.
int	nextDoc()
int	nextStartPosition()	Returns the next start position for the current doc.
float	positionsCost()	Return an estimation of the cost of using the positions of this Spans for any single document, but only after Spans.asTwoPhaseIterator() returned null.
int	startPosition()	Returns the start position in the current doc, or -1 when Spans.nextStartPosition() was not yet called on the current doc.
String	toString()
int	width()	Return the width of the match, which is typically used to sloppy freq.

Methods inherited from class org.apache.lucene.queries.spans.Spans

doCurrentSpans, doStartCurrentDoc

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

all, empty, range, slowAdvance

Methods inherited from class java.lang.Object

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

Field Detail

in

protected final Spans in

The wrapped spans instance.

Constructor Detail

FilterSpans

protected FilterSpans(Spans in)

Wrap the given Spans.

Method Detail

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

nextDoc

public final int nextDoc()
                  throws IOException

Specified by:

nextDoc in class DocIdSetIterator

Throws:

IOException

advance

public final int advance(int target)
                  throws IOException

Specified by:

advance in class DocIdSetIterator

Throws:

IOException

docID

public final int docID()

Specified by:

docID in class DocIdSetIterator

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 returns Spans.NO_MORE_POSITIONS.

Specified by:

nextStartPosition in class Spans

Throws:

IOException

startPosition

public final int startPosition()

Description copied from class: Spans

Returns the start position in the current doc, or -1 when Spans.nextStartPosition() was not yet called on the current doc. After the last start/end position at the current doc this returns Spans.NO_MORE_POSITIONS.

Specified by:

startPosition in class Spans

endPosition

public final int endPosition()

Description copied from class: Spans

Returns the end position for the current start position, or -1 when Spans.nextStartPosition() was not yet called on the current doc. After the last start/end position at the current doc this returns Spans.NO_MORE_POSITIONS.

Specified by:

endPosition in class Spans

width

public int width()

Description copied from class: Spans

Return the width of the match, which is typically used to sloppy freq. 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.

Specified by:

width in class Spans

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 after Spans.nextStartPosition(), and before Spans.NO_MORE_POSITIONS has been reached.

Specified by:

collect in class Spans

Parameters:

collector - a SpanCollector

Throws:

IOException

cost

public final long cost()

Specified by:

cost in class DocIdSetIterator

toString

public String toString()

Overrides:

toString in class Spans

asTwoPhaseIterator

public final TwoPhaseIterator asTwoPhaseIterator()

Description copied from class: Spans

Optional method: Return a TwoPhaseIterator view of this Scorer. A return value of null indicates that two-phase iteration is not supported.

Overrides:

asTwoPhaseIterator in class Spans

See Also:

Scorer.twoPhaseIterator()

positionsCost

public float positionsCost()

Description copied from class: Spans

Return an estimation of the cost of using the positions of this Spans for any single document, but only after Spans.asTwoPhaseIterator() returned null. Otherwise this method should not be called. The returned value is independent of the current document.

Specified by:

positionsCost in class Spans