MatchAllDocsQuery.cs

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/* 
 * 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 Lucene.Net.Index;
using IndexReader = Lucene.Net.Index.IndexReader;
using TermDocs = Lucene.Net.Index.TermDocs;
using ToStringUtils = Lucene.Net.Util.ToStringUtils;

namespace Lucene.Net.Search
{
    
    /// <summary> A query that matches all documents.
    /// 
    /// </summary>
    [Serializable]
    public class MatchAllDocsQuery:Query
    {
        
        public MatchAllDocsQuery():this(null)
        {
        }
        
        private System.String normsField;
        
        /// <param name="normsField">Field used for normalization factor (document boost). Null if nothing.
        /// </param>
        public MatchAllDocsQuery(System.String normsField)
        {
            this.normsField = normsField;
        }
        
        private class MatchAllScorer:Scorer
        {
            private void  InitBlock(MatchAllDocsQuery enclosingInstance)
            {
                this.enclosingInstance = enclosingInstance;
            }
            private MatchAllDocsQuery enclosingInstance;
            public MatchAllDocsQuery Enclosing_Instance
            {
                get
                {
                    return enclosingInstance;
                }
                
            }
            internal TermDocs termDocs;
            internal float score;
            internal byte[] norms;
            private int doc = - 1;
            
            internal MatchAllScorer(MatchAllDocsQuery enclosingInstance, IndexReader reader, Similarity similarity, Weight w, byte[] norms):base(similarity)
            {
                InitBlock(enclosingInstance);
                this.termDocs = reader.TermDocs(null);
                score = w.Value;
                this.norms = norms;
            }
            
            public override int DocID()
            {
                return doc;
            }
            
            public override int NextDoc()
            {
                return doc = termDocs.Next()?termDocs.Doc:NO_MORE_DOCS;
            }
            
            public override float Score()
            {
                return norms == null?score:score * Similarity.DecodeNorm(norms[DocID()]);
            }
            
            public override int Advance(int target)
            {
                return doc = termDocs.SkipTo(target)?termDocs.Doc:NO_MORE_DOCS;
            }
        }
        
        [Serializable]
        private class MatchAllDocsWeight:Weight
        {
            private void  InitBlock(MatchAllDocsQuery enclosingInstance)
            {
                this.enclosingInstance = enclosingInstance;
            }
            private MatchAllDocsQuery enclosingInstance;
            public MatchAllDocsQuery Enclosing_Instance
            {
                get
                {
                    return enclosingInstance;
                }
                
            }
            private Similarity similarity;
            private float queryWeight;
            private float queryNorm;
            
            public MatchAllDocsWeight(MatchAllDocsQuery enclosingInstance, Searcher searcher)
            {
                InitBlock(enclosingInstance);
                this.similarity = searcher.Similarity;
            }
            
            public override System.String ToString()
            {
                return "weight(" + Enclosing_Instance + ")";
            }

            public override Query Query
            {
                get { return Enclosing_Instance; }
            }

            public override float Value
            {
                get { return queryWeight; }
            }

            public override float GetSumOfSquaredWeights()
            {
                queryWeight = Enclosing_Instance.Boost;
                return queryWeight*queryWeight;
            }

            public override void  Normalize(float queryNorm)
            {
                this.queryNorm = queryNorm;
                queryWeight *= this.queryNorm;
            }
            
            public override Scorer Scorer(IndexReader reader, bool scoreDocsInOrder, bool topScorer)
            {
                return new MatchAllScorer(enclosingInstance, reader, similarity, this, Enclosing_Instance.normsField != null?reader.Norms(Enclosing_Instance.normsField):null);
            }
            
            public override Explanation Explain(IndexReader reader, int doc)
            {
                // explain query weight
                Explanation queryExpl = new ComplexExplanation(true, Value, "MatchAllDocsQuery, product of:");
                if (Enclosing_Instance.Boost != 1.0f)
                {
                    queryExpl.AddDetail(new Explanation(Enclosing_Instance.Boost, "boost"));
                }
                queryExpl.AddDetail(new Explanation(queryNorm, "queryNorm"));
                
                return queryExpl;
            }
        }
        
        public override Weight CreateWeight(Searcher searcher)
        {
            return new MatchAllDocsWeight(this, searcher);
        }
        
        public override void  ExtractTerms(System.Collections.Generic.ISet<Term> terms)
        {
        }
        
        public override System.String ToString(System.String field)
        {
            System.Text.StringBuilder buffer = new System.Text.StringBuilder();
            buffer.Append("*:*");
            buffer.Append(ToStringUtils.Boost(Boost));
            return buffer.ToString();
        }
        
        public  override bool Equals(System.Object o)
        {
            if (!(o is MatchAllDocsQuery))
                return false;
            MatchAllDocsQuery other = (MatchAllDocsQuery) o;
            return this.Boost == other.Boost;
        }
        
        public override int GetHashCode()
        {
            return BitConverter.ToInt32(BitConverter.GetBytes(Boost), 0) ^ 0x1AA71190;
        }
    }
}