forked from apache/lucenenet
/
PerFieldSimilarityWrapper.cs
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/
PerFieldSimilarityWrapper.cs
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namespace Lucene.Net.Search.Similarities
{
/*
* 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 AtomicReaderContext = Lucene.Net.Index.AtomicReaderContext;
using FieldInvertState = Lucene.Net.Index.FieldInvertState;
/// <summary>
/// Provides the ability to use a different <see cref="Similarity"/> for different fields.
/// <para/>
/// Subclasses should implement <see cref="Get(string)"/> to return an appropriate
/// <see cref="Similarity"/> (for example, using field-specific parameter values) for the field.
/// <para/>
/// @lucene.experimental
/// </summary>
public abstract class PerFieldSimilarityWrapper : Similarity
{
/// <summary>
/// Sole constructor. (For invocation by subclass
/// constructors, typically implicit.)
/// </summary>
public PerFieldSimilarityWrapper()
{
}
public override sealed long ComputeNorm(FieldInvertState state)
{
return Get(state.Name).ComputeNorm(state);
}
public override sealed SimWeight ComputeWeight(float queryBoost, CollectionStatistics collectionStats, params TermStatistics[] termStats)
{
PerFieldSimWeight weight = new PerFieldSimWeight();
weight.@delegate = Get(collectionStats.Field);
weight.delegateWeight = weight.@delegate.ComputeWeight(queryBoost, collectionStats, termStats);
return weight;
}
public override sealed SimScorer GetSimScorer(SimWeight weight, AtomicReaderContext context)
{
PerFieldSimWeight perFieldWeight = (PerFieldSimWeight)weight;
return perFieldWeight.@delegate.GetSimScorer(perFieldWeight.delegateWeight, context);
}
/// <summary>
/// Returns a <see cref="Similarity"/> for scoring a field.
/// </summary>
public abstract Similarity Get(string name);
internal class PerFieldSimWeight : SimWeight
{
internal Similarity @delegate;
internal SimWeight delegateWeight;
public override float GetValueForNormalization()
{
return delegateWeight.GetValueForNormalization();
}
public override void Normalize(float queryNorm, float topLevelBoost)
{
delegateWeight.Normalize(queryNorm, topLevelBoost);
}
}
}
}