/*
 * Copyright 2004 The Apache Software Foundation
 * 
 * Licensed 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 Monodoc.Lucene.Net.Index;
namespace Monodoc.Lucene.Net.Search
{
	
	/// <summary>Abstract base class providing a mechanism to restrict searches to a subset
	/// of an index. 
	/// </summary>
	[Serializable]
	public abstract class Filter
	{
		/// <summary>Returns a BitSet with true for documents which should be permitted in
		/// search results, and false for those that should not. 
		/// </summary>
		public abstract System.Collections.BitArray Bits(Monodoc.Lucene.Net.Index.IndexReader reader);
	}
}