org.ninit.models.bm25.BM25SingleBooleanScorer.java Source code

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Here is the source code for org.ninit.models.bm25.BM25SingleBooleanScorer.java

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package org.ninit.models.bm25;

/**
 * BM25SingleBooleanScorer.java
 *
 * Copyright (c) 2008 "Joaqun Prez-Iglesias"
 *
 * 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.
 */

import java.io.IOException;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.BM25TermScorer;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Similarity;
import org.ninit.models.bm25.BM25BooleanQuery.BooleanTermQuery;
import org.ninit.models.bm25f.BM25FTermScorer;
import org.ninit.models.bool.AbstractBooleanScorer;
import org.ninit.models.bool.MustBooleanScorer;
import org.ninit.models.bool.NotBooleanScorer;
import org.ninit.models.bool.ShouldBooleanScorer;

/**
 * BM25SingleBooleanScorer, calculates the total relevance value based boolean
 * expression, that has just one common operator (AND, OR, NOT) for all terms.<BR>
 * 
 * @author "Joaquin Perez-Iglesias"
 * 
 */
public class BM25SingleBooleanScorer extends Scorer {

    private AbstractBooleanScorer booleanScorer = null;

    public BM25SingleBooleanScorer(IndexReader reader, BooleanTermQuery[] termQuery, Similarity similarity)
            throws IOException {
        super(similarity);

        Scorer[] scorer = new Scorer[termQuery.length];
        for (int i = 0; i < scorer.length; i++) {
            scorer[i] = new BM25TermScorer(reader, termQuery[i].termQuery, similarity);
        }

        if (termQuery[0].occur == BooleanClause.Occur.MUST)
            this.booleanScorer = new MustBooleanScorer(similarity, scorer);
        else if (termQuery[0].occur == BooleanClause.Occur.SHOULD)
            this.booleanScorer = new ShouldBooleanScorer(similarity, scorer);
        else
            this.booleanScorer = new NotBooleanScorer(similarity, scorer, reader.numDocs());

    }

    public BM25SingleBooleanScorer(IndexReader reader, BooleanTermQuery[] termQuery, Similarity similarity,
            String[] fields, float[] boosts, float[] bParams) throws IOException {
        super(similarity);
        Scorer[] scorer = new Scorer[termQuery.length];

        for (int i = 0; i < scorer.length; i++) {
            scorer[i] = new BM25FTermScorer(reader, termQuery[i].termQuery, fields, boosts, bParams, similarity);
        }

        if (termQuery[0].occur == BooleanClause.Occur.MUST)
            this.booleanScorer = new MustBooleanScorer(similarity, scorer);
        else if (termQuery[0].occur == BooleanClause.Occur.SHOULD)
            this.booleanScorer = new ShouldBooleanScorer(similarity, scorer);
        else
            this.booleanScorer = new NotBooleanScorer(similarity, scorer, reader.numDocs());

    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.lucene.search.Scorer#doc()
     */
    @Override
    public int doc() {
        return booleanScorer.doc();
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.lucene.search.Scorer#explain(int)
     */
    @Override
    public Explanation explain(int doc) throws IOException {
        Explanation result = new Explanation();
        result.setDescription("Total");
        Explanation detail = this.booleanScorer.explain(doc);
        result.addDetail(detail);
        result.setValue(detail.getValue());
        return result;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.lucene.search.Scorer#next()
     */
    @Override
    public boolean next() throws IOException {
        return booleanScorer.next();
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.lucene.search.Scorer#score()
     */
    @Override
    public float score() throws IOException {
        return booleanScorer.score();

    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.lucene.search.Scorer#skipTo(int)
     */
    @Override
    public boolean skipTo(int target) throws IOException {
        while (this.next() && this.doc() < target) {
        }

        return this.doc() == target;
    }

}