org.apache.lucene.search
Class SpanFilter

java.lang.Object
  extended by org.apache.lucene.search.Filter
      extended by org.apache.lucene.search.SpanFilter
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
CachingSpanFilter, SpanQueryFilter

public abstract class SpanFilter
extends Filter

Abstract base class providing a mechanism to restrict searches to a subset of an index and also maintains and returns position information. This is useful if you want to compare the positions from a SpanQuery with the positions of items in a filter. For instance, if you had a SpanFilter that marked all the occurrences of the word "foo" in documents, and then you entered a new SpanQuery containing bar, you could not only filter by the word foo, but you could then compare position information for post processing.

See Also:
Serialized Form

Constructor Summary
SpanFilter()
           
 
Method Summary
abstract  SpanFilterResult bitSpans(IndexReader reader)
          Returns a SpanFilterResult with true for documents which should be permitted in search results, and false for those that should not and Spans for where the true docs match.
 
Methods inherited from class org.apache.lucene.search.Filter
getDocIdSet
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SpanFilter

public SpanFilter()
Method Detail

bitSpans

public abstract SpanFilterResult bitSpans(IndexReader reader)
                                   throws IOException
Returns a SpanFilterResult with true for documents which should be permitted in search results, and false for those that should not and Spans for where the true docs match.

Parameters:
reader - The IndexReader to load position and DocIdSet information from
Returns:
A SpanFilterResult
Throws:
IOException - if there was an issue accessing the necessary information


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