org.apache.lucene.search.spans
Class NearSpansOrdered

java.lang.Object
  org.apache.lucene.search.spans.Spans
      org.apache.lucene.search.spans.NearSpansOrdered

public class NearSpansOrdered
extends Spans

A Spans that is formed from the ordered subspans of a SpanNearQuery where the subspans do not overlap and have a maximum slop between them.

The formed spans only contains minimum slop matches.
The matching slop is computed from the distance(s) between the non overlapping matching Spans.
Successive matches are always formed from the successive Spans of the SpanNearQuery.

The formed spans may contain overlaps when the slop is at least 1. For example, when querying using

t1 t2 t3

with slop at least 1, the fragment:

t1 t2 t1 t3 t2 t3

matches twice:

t1 t2 .. t3      

      t1 .. t2 t3

Expert: Only public for subclassing. Most implementations should not need this class

Constructor Summary

NearSpansOrdered(SpanNearQuery spanNearQuery, IndexReader reader)

NearSpansOrdered(SpanNearQuery spanNearQuery, IndexReader reader, boolean collectPayloads)

Method Summary

int	doc() Returns the document number of the current match.
int	end() Returns the end position of the current match.
Collection<byte[]>	getPayload() Returns the payload data for the current span.
Spans[]	getSubSpans()
boolean	isPayloadAvailable() Checks if a payload can be loaded at this position.
boolean	next() Move to the next match, returning true iff any such exists.
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()

Methods inherited from class java.lang.Object

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

Constructor Detail

NearSpansOrdered

public NearSpansOrdered(SpanNearQuery spanNearQuery,
                        IndexReader reader)
                 throws IOException

Throws:

IOException

NearSpansOrdered

public NearSpansOrdered(SpanNearQuery spanNearQuery,
                        IndexReader reader,
                        boolean collectPayloads)
                 throws IOException

Throws:

IOException

Method Detail

doc

public int doc()

Description copied from class: Spans

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

Specified by:

doc in class Spans

start

public int start()

Description copied from class: Spans

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

Specified by:

start in class Spans

end

public int end()

Description copied from class: Spans

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

Specified by:

end in class Spans

getSubSpans

public Spans[] getSubSpans()

getPayload

public Collection<byte[]> getPayload()
                              throws IOException

Description copied from class: Spans

Returns the payload data for the current span. This is invalid until Spans.next() is called for the first time. This method must not be called more than once after each call of Spans.next(). However, most payloads are loaded lazily, so if the payload data for the current position is not needed, this method may not be called at all for performance reasons. An ordered SpanQuery does not lazy load, so if you have payloads in your index and you do not want ordered SpanNearQuerys to collect payloads, you can disable collection with a constructor option.

Note that the return type is a collection, thus the ordering should not be relied upon.

Specified by:

getPayload in class Spans

Returns:

a List of byte arrays containing the data of this payload, otherwise null if isPayloadAvailable is false

Throws:

IOException

isPayloadAvailable

public boolean isPayloadAvailable()

Description copied from class: Spans

Checks if a payload can be loaded at this position.

Payloads can only be loaded once per call to Spans.next().

Specified by:

isPayloadAvailable in class Spans

Returns:

true if there is a payload available at this position that can be loaded

next

public boolean next()
             throws IOException

Description copied from class: Spans

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

Specified by:

next in class Spans

Throws:

IOException

skipTo

public boolean skipTo(int target)
               throws IOException

Description copied from class: 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 class Spans

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object