org.apache.lucene.search.spans

Class FilterSpans

java.lang.Object

org.apache.lucene.search.spans.Spans

org.apache.lucene.search.spans.FilterSpans

public class FilterSpans
extends Spans

A Spans implementation which allows wrapping another spans instance and override some selected methods.

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor and Description
FilterSpans(Spans in) Wrap the given Spans.

Method Summary

Methods

Modifier and Type	Method and Description
long	cost() Returns the estimated cost of this spans.
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.
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

Field Detail

in

protected final Spans in

The wrapped spans instance.

Constructor Detail

FilterSpans

public FilterSpans(Spans in)

Wrap the given Spans.

Method Detail

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.

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.

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

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

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 - if there is a low-level I/O error

isPayloadAvailable

public boolean isPayloadAvailable()
                           throws IOException

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

Throws:

IOException

cost

public long cost()

Description copied from class: Spans

Returns the estimated cost of this spans.

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 Spans

toString

public String toString()

Overrides:

toString in class Object