/*
* 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 IndexReaderLucene.Net.Index.IndexReader;
using TermLucene.Net.Index.Term;
using TermDocsLucene.Net.Index.TermDocs;
using ToStringUtilsLucene.Net.Util.ToStringUtils;
namespace Lucene.Net.Search{
/// <summary>A Query that matches documents containing a term.
/// This may be combined with other terms with a {@link BooleanQuery}.
/// </summary>
[Serializable]
public class TermQuery : Query
{
private Term term;
[Serializable]
private class TermWeight : Weight
{
private void InitBlock(TermQuery enclosingInstance)
{
this.enclosingInstance = enclosingInstance;
}
private TermQuery enclosingInstance;
public TermQuery Enclosing_Instance
{
get
{
return enclosingInstance;
}
}
private Similarity similarity;
private float value_Renamed;
private float idf;
private float queryNorm;
private float queryWeight;
public TermWeight(TermQuery enclosingInstance, Searcher searcher)
{
InitBlock(enclosingInstance);
this.similarity = Enclosing_Instance.GetSimilarity(searcher);
idf = similarity.Idf(Enclosing_Instance.term, searcher); // compute idf
}
public override System.String ToString()
{
return "weight(" + Enclosing_Instance + ")";
}
public virtual Query GetQuery()
{
return Enclosing_Instance;
}
public virtual float GetValue()
{
return value_Renamed;
}
public virtual float SumOfSquaredWeights()
{
queryWeight = idf * Enclosing_Instance.GetBoost(); // compute query weight
return queryWeight * queryWeight; // square it
}
public virtual void Normalize(float queryNorm)
{
this.queryNorm = queryNorm;
queryWeight *= queryNorm; // normalize query weight
value_Renamed = queryWeight * idf; // idf for document
}
public virtual Scorer Scorer(IndexReader reader)
{
TermDocs termDocs = reader.TermDocs(Enclosing_Instance.term);
if (termDocs == null)
return null;
return new TermScorer(this, termDocs, similarity, reader.Norms(Enclosing_Instance.term.Field()));
}
public virtual Explanation Explain(IndexReader reader, int doc)
{
Explanation result = new Explanation();
result.SetDescription("weight(" + GetQuery() + " in " + doc + "), product of:");
Explanation idfExpl = new Explanation(idf, "idf(docFreq=" + reader.DocFreq(Enclosing_Instance.term) + ")");
// explain query weight
Explanation queryExpl = new Explanation();
queryExpl.SetDescription("queryWeight(" + GetQuery() + "), product of:");
Explanation boostExpl = new Explanation(Enclosing_Instance.GetBoost(), "boost");
if (Enclosing_Instance.GetBoost() != 1.0f)
queryExpl.AddDetail(boostExpl);
queryExpl.AddDetail(idfExpl);
Explanation queryNormExpl = new Explanation(queryNorm, "queryNorm");
queryExpl.AddDetail(queryNormExpl);
queryExpl.SetValue(boostExpl.GetValue() * idfExpl.GetValue() * queryNormExpl.GetValue());
result.AddDetail(queryExpl);
// explain field weight
System.String field = Enclosing_Instance.term.Field();
Explanation fieldExpl = new Explanation();
fieldExpl.SetDescription("fieldWeight(" + Enclosing_Instance.term + " in " + doc + "), product of:");
Explanation tfExpl = Scorer(reader).Explain(doc);
fieldExpl.AddDetail(tfExpl);
fieldExpl.AddDetail(idfExpl);
Explanation fieldNormExpl = new Explanation();
byte[] fieldNorms = reader.Norms(field);
float fieldNorm = fieldNorms != null ? Similarity.DecodeNorm(fieldNorms[doc]) : 0.0f;
fieldNormExpl.SetValue(fieldNorm);
fieldNormExpl.SetDescription("fieldNorm(field=" + field + ", doc=" + doc + ")");
fieldExpl.AddDetail(fieldNormExpl);
fieldExpl.SetValue(tfExpl.GetValue() * idfExpl.GetValue() * fieldNormExpl.GetValue());
result.AddDetail(fieldExpl);
// combine them
result.SetValue(queryExpl.GetValue() * fieldExpl.GetValue());
if (queryExpl.GetValue() == 1.0f)
return fieldExpl;
return result;
}
}
/// <summary>Constructs a query for the term <code>t</code>. </summary>
public TermQuery(Term t)
{
term = t;
}
/// <summary>Returns the term of this query. </summary>
public virtual Term GetTerm()
{
return term;
}
protected internal override Weight CreateWeight(Searcher searcher)
{
return new TermWeight(this, searcher);
}
public override void ExtractTerms(System.Collections.Hashtable terms)
{
Term term = GetTerm();
terms.Add(term, term);
}
/// <summary>Prints a user-readable version of this query. </summary>
public override System.String ToString(System.String field)
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
if (!term.Field().Equals(field))
{
buffer.Append(term.Field());
buffer.Append(":");
}
buffer.Append(term.Text());
buffer.Append(ToStringUtils.Boost(GetBoost()));
return buffer.ToString();
}
/// <summary>Returns true iff <code>o</code> is equal to this. </summary>
public override bool Equals(System.Object o)
{
if (!(o is TermQuery))
return false;
TermQuery other = (TermQuery) o;
return (this.GetBoost() == other.GetBoost()) && this.term.Equals(other.term);
}
/// <summary>Returns a hash code value for this object.</summary>
public override int GetHashCode()
{
return BitConverter.ToInt32(BitConverter.GetBytes(GetBoost()), 0) ^ term.GetHashCode();
}
// {{Aroush-1.9}} Do we need this?!
public override System.Object Clone()
{
return null;
}
}
}
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