org.apache.lucene.chunk
Class SpanDechunkingQuery

Object
  Query
      SpanQuery
          SpanDechunkingQuery

All Implemented Interfaces:

Serializable, Cloneable

public class SpanDechunkingQuery
extends SpanQuery

Wraps a SpanQuery, converting chunk spans to look like they're all part of the main document. Uses a DocNumMap to find out the mapping from chunks to the main document. The start and end offsets in each span are then multiplied by the chunk offset times the non-overlapping word count per chunk.

For instance, say that main document 812 has chunks 813-945. And say that the chunk size is 125 words with an overlap of 25. Spans in chunk 813 will have their offsets unchanged; those in 814 will range from 100-199, those in 815 will range from 200-299, etc.

Warning: The spans that result from this query might not be in strict start/end order. Thus, this query is only suitable as a top-level span query, and never as part of another span query.

See Also:

Serialized Form

Field Summary

private DocNumMap	docNumMap
private SpanQuery	wrapped

Constructor Summary

SpanDechunkingQuery(SpanQuery wrap)
Construct a query that will mark the results of a normal span query.

Method Summary

String	getField() Returns the name of the field matched by this query.
Spans	getSpans(IndexReader reader, Searcher searcher) Expert: Returns the matches for this query in an index.
Query[]	getSubQueries()
Collection	getTerms() Returns a collection of all terms matched by this query.
SpanQuery	getWrapped() Retrieve the SpanQuery being wrapped
Query	rewrite(IndexReader reader)
void	setDocNumMap(DocNumMap docNumMap) Establish a document number map.
String	toString(String field)

Methods inherited from class SpanQuery

createWeight, getSpanRecording, setSpanRecording

Methods inherited from class Query

clone, combine, extractTerms, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight

Methods inherited from class Object

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

Field Detail

wrapped

private SpanQuery wrapped

docNumMap

private DocNumMap docNumMap

Constructor Detail

SpanDechunkingQuery

public SpanDechunkingQuery(SpanQuery wrap)

Construct a query that will mark the results of a normal span query.

Method Detail

setDocNumMap

public void setDocNumMap(DocNumMap docNumMap)

Establish a document number map. Must be called before getSpans().

getWrapped

public SpanQuery getWrapped()

Retrieve the SpanQuery being wrapped

getField

public String getField()

Description copied from class: SpanQuery

Returns the name of the field matched by this query.

Specified by:

getField in class SpanQuery

getTerms

public Collection getTerms()

Description copied from class: SpanQuery

Returns a collection of all terms matched by this query.

Specified by:

getTerms in class SpanQuery

getSubQueries

public Query[] getSubQueries()

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Overrides:

rewrite in class Query

Throws:

IOException

toString

public String toString(String field)

Specified by:

toString in class Query

getSpans

public Spans getSpans(IndexReader reader,
                      Searcher searcher)
               throws IOException

Description copied from class: SpanQuery

Expert: Returns the matches for this query in an index. Used internally to search for spans.

Specified by:

getSpans in class SpanQuery

Throws:

IOException