org.apache.lucene.search
Class SpanFilter

java.lang.Object
  org.apache.lucene.search.Filter
      org.apache.lucene.search.SpanFilter

All Implemented Interfaces:

java.io.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

bits, 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 java.io.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:

java.io.IOException - if there was an issue accessing the necessary information