org.apache.lucene.search.spans
Class NearSpans

Object
  NearSpans

All Implemented Interfaces:

Spans

 class NearSpans
extends Object
implements Spans

Calculates spans that match several queries "near" each other. In-order matches score higher than out-of-order matches.

Nested Class Summary

private class

NearSpans.SpansCell Wraps a Spans, and can be used to form a linked list.

Field Summary

private NearSpans.SpansCell	firstCell
private boolean	firstTime
private boolean	inOrder
private NearSpans.SpansCell	lastCell
private boolean	more
private int	nCellsInList
private List	ordered
private SpanNearQuery	query
private Similarity	similarity
private int	slop
private int	totalLength
private float	totalScore
private int	totalSlop

Constructor Summary

NearSpans(SpanNearQuery query, IndexReader reader, Searcher searcher)

Method Summary

private boolean	advanceOneCell()
private boolean	atMatch()
private boolean	checkSlop()
int	doc() Returns the document number of the current match.
int	end() Returns the end position of the current match.
Explanation	explain() Returns an explanation of how the score was arrived at.
private void	initList(int target)
private boolean	matchIsOrdered()
boolean	next() Move to the next match, returning true iff any such exists.
float	score() Returns the score of the current match.
boolean	skipTo(int target) Skips to the first match beyond the current, whose document number is greater than or equal to target.
int	start() Returns the start position of the current match.
String	toString()
private int	totalSlop()

Methods inherited from class Object

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

Field Detail

query

private SpanNearQuery query

similarity

private Similarity similarity

ordered

private List ordered

slop

private int slop

inOrder

private boolean inOrder

firstCell

private NearSpans.SpansCell firstCell

lastCell

private NearSpans.SpansCell lastCell

nCellsInList

private int nCellsInList

totalLength

private int totalLength

totalScore

private float totalScore

totalSlop

private int totalSlop

more

private boolean more

firstTime

private boolean firstTime

Constructor Detail

NearSpans

public NearSpans(SpanNearQuery query,
                 IndexReader reader,
                 Searcher searcher)
          throws IOException

Throws:

IOException

Method Detail

next

public boolean next()
             throws IOException

Description copied from interface: Spans

Move to the next match, returning true iff any such exists.

Specified by:

next in interface Spans

Throws:

IOException

advanceOneCell

private boolean advanceOneCell()
                        throws IOException

Throws:

IOException

skipTo

public boolean skipTo(int target)
               throws IOException

Description copied from interface: Spans

Skips to the first match beyond the current, whose document number is greater than or equal to target.

Returns true iff there is such a match.

Behaves as if written:

   boolean skipTo(int target) {
     do {
       if (!next())
              return false;
     } while (target > doc());
     return true;
   }
 

Most implementations are considerably more efficient than that.

Specified by:

skipTo in interface Spans

Throws:

IOException

doc

public int doc()

Description copied from interface: Spans

Returns the document number of the current match. Initially invalid.

Specified by:

doc in interface Spans

start

public int start()

Description copied from interface: Spans

Returns the start position of the current match. Initially invalid.

Specified by:

start in interface Spans

end

public int end()

Description copied from interface: Spans

Returns the end position of the current match. Initially invalid.

Specified by:

end in interface Spans

score

public float score()

Description copied from interface: Spans

Returns the score of the current match. Initially invalid.

Specified by:

score in interface Spans

toString

public String toString()

Overrides:

toString in class Object

initList

private void initList(int target)
               throws IOException

Throws:

IOException

atMatch

private boolean atMatch()

checkSlop

private boolean checkSlop()

matchIsOrdered

private boolean matchIsOrdered()

totalSlop

private int totalSlop()

explain

public Explanation explain()
                    throws IOException

Description copied from interface: Spans

Returns an explanation of how the score was arrived at. Initially invalid.

Specified by:

explain in interface Spans

Throws:

IOException