/*
* 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 System.Runtime.InteropServices;
using IndexReader = Lucene.Net.Index.IndexReader;
namespace Lucene.Net.Search
{
/// Wraps another SpanFilter's result and caches it. The purpose is to allow
/// filters to simply filter, and then wrap with this class to add caching.
///
[Serializable]
public class CachingSpanFilter:SpanFilter
{
protected internal SpanFilter filter;
/// A transient Filter cache.
[NonSerialized]
protected internal System.Collections.IDictionary cache;
/// Filter to cache results of
///
public CachingSpanFilter(SpanFilter filter)
{
this.filter = filter;
}
/// Use {@link #GetDocIdSet(IndexReader)} instead.
///
[Obsolete("Use GetDocIdSet(IndexReader) instead.")]
public override System.Collections.BitArray Bits(IndexReader reader)
{
SpanFilterResult result = GetCachedResult(reader);
return result != null?result.GetBits():null;
}
public override DocIdSet GetDocIdSet(IndexReader reader)
{
SpanFilterResult result = GetCachedResult(reader);
return result != null?result.GetDocIdSet():null;
}
private SpanFilterResult GetCachedResult(IndexReader reader)
{
SpanFilterResult result = null;
if (cache == null)
{
cache = new SupportClass.WeakHashTable();
}
lock (cache.SyncRoot)
{
// check cache
result = (SpanFilterResult) cache[reader];
if (result == null)
{
result = filter.BitSpans(reader);
cache[reader] = result;
}
}
return result;
}
public override SpanFilterResult BitSpans(IndexReader reader)
{
return GetCachedResult(reader);
}
public override System.String ToString()
{
return "CachingSpanFilter(" + filter + ")";
}
public override bool Equals(System.Object o)
{
if (!(o is CachingSpanFilter))
return false;
return this.filter.Equals(((CachingSpanFilter) o).filter);
}
public override int GetHashCode()
{
return filter.GetHashCode() ^ 0x1117BF25;
}
}
}