/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using IndexReader = Lucene.Net.Index.IndexReader;
namespace Lucene.Net.Search
{
/// 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.
///
[Serializable]
public abstract class SpanFilter:Filter
{
/// 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.
///
/// The to load position and DocIdSet information from
///
/// A
///
/// java.io.IOException if there was an issue accessing the necessary information
///
///
public abstract SpanFilterResult BitSpans(IndexReader reader);
}
}