MultiPhraseQuery.cs
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上传日期:2013-09-30
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文件大小:10k
- /*
- * 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 IndexReader = Lucene.Net.Index.IndexReader;
- using MultipleTermPositions = Lucene.Net.Index.MultipleTermPositions;
- using Term = Lucene.Net.Index.Term;
- using TermPositions = Lucene.Net.Index.TermPositions;
- using ToStringUtils = Lucene.Net.Util.ToStringUtils;
- namespace Lucene.Net.Search
- {
-
- /// <summary> MultiPhraseQuery is a generalized version of PhraseQuery, with an added
- /// method {@link #Add(Term[])}.
- /// To use this class, to search for the phrase "Microsoft app*" first use
- /// add(Term) on the term "Microsoft", then find all terms that have "app" as
- /// prefix using IndexReader.terms(Term), and use MultiPhraseQuery.add(Term[]
- /// terms) to add them to the query.
- ///
- /// </summary>
- /// <author> Anders Nielsen
- /// </author>
- /// <version> 1.0
- /// </version>
- [Serializable]
- public class MultiPhraseQuery : Query
- {
- private System.String field;
- private System.Collections.ArrayList termArrays = new System.Collections.ArrayList();
- private System.Collections.ArrayList positions = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10));
-
- private int slop = 0;
-
- /// <summary>Sets the phrase slop for this query.</summary>
- /// <seealso cref="PhraseQuery.SetSlop(int)">
- /// </seealso>
- public virtual void SetSlop(int s)
- {
- slop = s;
- }
-
- /// <summary>Sets the phrase slop for this query.</summary>
- /// <seealso cref="PhraseQuery.GetSlop()">
- /// </seealso>
- public virtual int GetSlop()
- {
- return slop;
- }
-
- /// <summary>Add a single term at the next position in the phrase.</summary>
- /// <seealso cref="PhraseQuery.Add(Term)">
- /// </seealso>
- public virtual void Add(Term term)
- {
- Add(new Term[]{term});
- }
-
- /// <summary>Add multiple terms at the next position in the phrase. Any of the terms
- /// may match.
- ///
- /// </summary>
- /// <seealso cref="PhraseQuery.Add(Term)">
- /// </seealso>
- public virtual void Add(Term[] terms)
- {
- int position = 0;
- if (positions.Count > 0)
- position = ((System.Int32) positions[positions.Count - 1]) + 1;
-
- Add(terms, position);
- }
-
- /// <summary> Allows to specify the relative position of terms within the phrase.
- ///
- /// </summary>
- /// <seealso cref="PhraseQuery.Add(Term, int)">
- /// </seealso>
- /// <param name="terms">
- /// </param>
- /// <param name="position">
- /// </param>
- public virtual void Add(Term[] terms, int position)
- {
- if (termArrays.Count == 0)
- field = terms[0].Field();
-
- for (int i = 0; i < terms.Length; i++)
- {
- if ((System.Object) terms[i].Field() != (System.Object) field)
- {
- throw new System.ArgumentException("All phrase terms must be in the same field (" + field + "): " + terms[i]);
- }
- }
-
- termArrays.Add(terms);
- positions.Add((System.Int32) position);
- }
-
- /// <summary> Returns the relative positions of terms in this phrase.</summary>
- public virtual int[] GetPositions()
- {
- int[] result = new int[positions.Count];
- for (int i = 0; i < positions.Count; i++)
- result[i] = ((System.Int32) positions[i]);
- return result;
- }
-
- [Serializable]
- private class MultiPhraseWeight : Weight
- {
- private void InitBlock(MultiPhraseQuery enclosingInstance)
- {
- this.enclosingInstance = enclosingInstance;
- }
- private MultiPhraseQuery enclosingInstance;
- public MultiPhraseQuery Enclosing_Instance
- {
- get
- {
- return enclosingInstance;
- }
-
- }
- private Similarity similarity;
- private float value_Renamed;
- private float idf;
- private float queryNorm;
- private float queryWeight;
-
- public MultiPhraseWeight(MultiPhraseQuery enclosingInstance, Searcher searcher)
- {
- InitBlock(enclosingInstance);
- this.similarity = Enclosing_Instance.GetSimilarity(searcher);
-
- // compute idf
- System.Collections.IEnumerator i = Enclosing_Instance.termArrays.GetEnumerator();
- while (i.MoveNext())
- {
- Term[] terms = (Term[]) i.Current;
- for (int j = 0; j < terms.Length; j++)
- {
- idf += Enclosing_Instance.GetSimilarity(searcher).Idf(terms[j], searcher);
- }
- }
- }
-
- 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)
- {
- if (Enclosing_Instance.termArrays.Count == 0)
- // optimize zero-term case
- return null;
-
- TermPositions[] tps = new TermPositions[Enclosing_Instance.termArrays.Count];
- for (int i = 0; i < tps.Length; i++)
- {
- Term[] terms = (Term[]) Enclosing_Instance.termArrays[i];
-
- TermPositions p;
- if (terms.Length > 1)
- p = new MultipleTermPositions(reader, terms);
- else
- p = reader.TermPositions(terms[0]);
-
- if (p == null)
- return null;
-
- tps[i] = p;
- }
-
- if (Enclosing_Instance.slop == 0)
- return new ExactPhraseScorer(this, tps, Enclosing_Instance.GetPositions(), similarity, reader.Norms(Enclosing_Instance.field));
- else
- return new SloppyPhraseScorer(this, tps, Enclosing_Instance.GetPositions(), similarity, Enclosing_Instance.slop, reader.Norms(Enclosing_Instance.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(" + GetQuery() + ")");
-
- // 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
- Explanation fieldExpl = new Explanation();
- fieldExpl.SetDescription("fieldWeight(" + GetQuery() + " in " + doc + "), product of:");
-
- Explanation tfExpl = Scorer(reader).Explain(doc);
- fieldExpl.AddDetail(tfExpl);
- fieldExpl.AddDetail(idfExpl);
-
- Explanation fieldNormExpl = new Explanation();
- byte[] fieldNorms = reader.Norms(Enclosing_Instance.field);
- float fieldNorm = fieldNorms != null ? Similarity.DecodeNorm(fieldNorms[doc]) : 0.0f;
- fieldNormExpl.SetValue(fieldNorm);
- fieldNormExpl.SetDescription("fieldNorm(field=" + Enclosing_Instance.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;
- }
- }
-
- public override Query Rewrite(IndexReader reader)
- {
- if (termArrays.Count == 1)
- {
- // optimize one-term case
- Term[] terms = (Term[]) termArrays[0];
- BooleanQuery boq = new BooleanQuery(true);
- for (int i = 0; i < terms.Length; i++)
- {
- boq.Add(new TermQuery(terms[i]), BooleanClause.Occur.SHOULD);
- }
- boq.SetBoost(GetBoost());
- return boq;
- }
- else
- {
- return this;
- }
- }
-
- protected internal override Weight CreateWeight(Searcher searcher)
- {
- return new MultiPhraseWeight(this, searcher);
- }
-
- /// <summary>Prints a user-readable version of this query. </summary>
- public override System.String ToString(System.String f)
- {
- System.Text.StringBuilder buffer = new System.Text.StringBuilder();
- if (!field.Equals(f))
- {
- buffer.Append(field);
- buffer.Append(":");
- }
-
- buffer.Append(""");
- System.Collections.IEnumerator i = termArrays.GetEnumerator();
- while (i.MoveNext())
- {
- Term[] terms = (Term[]) i.Current;
- if (terms.Length > 1)
- {
- buffer.Append("(");
- for (int j = 0; j < terms.Length; j++)
- {
- buffer.Append(terms[j].Text());
- if (j < terms.Length - 1)
- buffer.Append(" ");
- }
- buffer.Append(")");
- }
- else
- {
- buffer.Append(terms[0].Text());
- }
- if (i.MoveNext())
- buffer.Append(" ");
- }
- buffer.Append(""");
-
- if (slop != 0)
- {
- buffer.Append("~");
- buffer.Append(slop);
- }
-
- buffer.Append(ToStringUtils.Boost(GetBoost()));
-
- return buffer.ToString();
- }
- // {{Aroush-1.9}} Do we need this?!
- override public System.Object Clone()
- {
- return null;
- }
- }
- }