QueryFilter.cs
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上传日期:2013-09-30
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- /*
- * 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 System.Runtime.InteropServices;
- using IndexReader = Lucene.Net.Index.IndexReader;
- namespace Lucene.Net.Search
- {
-
- /// <summary>Constrains search results to only match those which also match a provided
- /// query. Results are cached, so that searches after the first on the same
- /// index using this filter are much faster.
- ///
- /// <p> This could be used, for example, with a {@link RangeQuery} on a suitably
- /// formatted date field to implement date filtering. One could re-use a single
- /// QueryFilter that matches, e.g., only documents modified within the last
- /// week. The QueryFilter and RangeQuery would only need to be reconstructed
- /// once per day.
- ///
- /// </summary>
- /// <version> $Id: QueryFilter.java 328729 2005-10-26 21:05:35Z yonik $
- /// </version>
- [Serializable]
- public class QueryFilter : Filter
- {
- private class AnonymousClassHitCollector : HitCollector
- {
- public AnonymousClassHitCollector(System.Collections.BitArray bits, QueryFilter enclosingInstance)
- {
- InitBlock(bits, enclosingInstance);
- }
- private void InitBlock(System.Collections.BitArray bits, QueryFilter enclosingInstance)
- {
- this.bits = bits;
- this.enclosingInstance = enclosingInstance;
- }
- private System.Collections.BitArray bits;
- private QueryFilter enclosingInstance;
- public QueryFilter Enclosing_Instance
- {
- get
- {
- return enclosingInstance;
- }
-
- }
- public override void Collect(int doc, float score)
- {
- bits.Set(doc, true); // set bit for hit
- }
- }
- private Query query;
- [NonSerialized]
- private System.Collections.Hashtable cache = null;
-
- /// <summary>Constructs a filter which only matches documents matching
- /// <code>query</code>.
- /// </summary>
- public QueryFilter(Query query)
- {
- this.query = query;
- }
-
- public override System.Collections.BitArray Bits(IndexReader reader)
- {
-
- if (cache == null)
- {
- cache = new System.Collections.Hashtable();
- }
-
- lock (cache.SyncRoot)
- {
- // check cache
- System.Collections.BitArray cached = (System.Collections.BitArray) cache[reader];
- if (cached != null)
- {
- return cached;
- }
- }
-
- System.Collections.BitArray bits = new System.Collections.BitArray((reader.MaxDoc() % 64 == 0?reader.MaxDoc() / 64:reader.MaxDoc() / 64 + 1) * 64);
-
- new IndexSearcher(reader).Search(query, new AnonymousClassHitCollector(bits, this));
-
- lock (cache.SyncRoot)
- {
- // update cache
- cache[reader] = bits;
- }
-
- return bits;
- }
-
- public override System.String ToString()
- {
- return "QueryFilter(" + query + ")";
- }
-
- public override bool Equals(System.Object o)
- {
- if (!(o is QueryFilter))
- return false;
- return this.query.Equals(((QueryFilter) o).query);
- }
-
- public override int GetHashCode()
- {
- return query.GetHashCode() ^ (unchecked((int) 0x923F64B9L)); // {{Aroush-1.9}} Is this OK?!
- }
- }
- }