/*
* 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 IndexReaderLucene.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?!
}
}
}
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