org.apache.lucene.search.spans

Class TermSpans

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

org.apache.lucene.search.spans.Spans

org.apache.lucene.search.spans.TermSpans

public class TermSpans
extends Spans

Expert: Public for extension only. This does not work correctly for terms that indexed at position Integer.MAX_VALUE.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	count
protected int	doc
protected int	freq
protected int	position
protected PostingsEnum	postings
protected boolean	readPayload
protected Term	term

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

NO_MORE_POSITIONS

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

NO_MORE_DOCS

Constructor Summary

Constructors

Constructor and Description
TermSpans(Similarity.SimScorer scorer, PostingsEnum postings, Term term, float positionsCost)

Method Summary

Modifier and Type	Method and 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.
void	collect(SpanCollector collector) Collect postings data from the leaves of the current Spans.
long	cost() Returns the estimated cost of this DocIdSetIterator.
int	docID() Returns the following: -1 if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
int	endPosition() Returns the end position for the current start position, or -1 when Spans.nextStartPosition() was not yet called on the current doc.
PostingsEnum	getPostings()
int	nextDoc() Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.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 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 compute the slop factor.

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

asTwoPhaseIterator, doCurrentSpans, doStartCurrentDoc

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

all, empty, slowAdvance

Methods inherited from class java.lang.Object

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

Field Detail

postings

protected final PostingsEnum postings

term

protected final Term term

doc

protected int doc

freq

protected int freq

count

protected int count

position

protected int position

readPayload

protected boolean readPayload

Constructor Detail

TermSpans

public TermSpans(Similarity.SimScorer scorer,
                 PostingsEnum postings,
                 Term term,
                 float positionsCost)

Method Detail

nextDoc

public 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, or DocIdSetIterator.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 class DocIdSetIterator

Throws:

IOException

advance

public 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 returns DocIdSetIterator.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 class DocIdSetIterator

Throws:

IOException

docID

public int docID()

Description copied from class: DocIdSetIterator

Returns the following:

• -1 if DocIdSetIterator.nextDoc() or DocIdSetIterator.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 class DocIdSetIterator

nextStartPosition

public 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 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 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 compute the slop 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.

Specified by:

width in class Spans

cost

public long cost()

Description copied from class: DocIdSetIterator

Returns the estimated cost of this DocIdSetIterator.

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 class DocIdSetIterator

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

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

toString

public String toString()

Overrides:

toString in class Spans

getPostings

public PostingsEnum getPostings()