org.tallison.lucene.search.concordance.util.SimpleTargetCounter.java Source code

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Here is the source code for org.tallison.lucene.search.concordance.util.SimpleTargetCounter.java

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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.
 */
package org.tallison.lucene.search.concordance.util;

import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.TotalHitCountCollector;
import org.apache.lucene.search.Weight;
import org.tallison.lucene.search.concordance.windowvisitor.TargetVisitor;

public class SimpleTargetCounter {

    /**
     * Simple utility class to perform basic term frequency/document frequency
     * counts on the individual terms within a query.  This relies on
     * IndexReader and does not perform any concordance search/retrieval;
     * it is, therefore, very fast.
     * <p>
     * If you want to visit more than basic terms (e.g. SpanNear),
     * see {@link TargetVisitor}
     *
     * @param query query
     * @param searcher searcher
     * @return target term results
     * @throws java.io.IOException if there is an IOException from the searcher
     */
    public SimpleTargetTermResults searchSingleTerms(Query query, IndexSearcher searcher) throws IOException {
        Query tmpQ = query.rewrite(searcher.getIndexReader());
        Set<Term> terms = new HashSet<>();
        Weight weight = tmpQ.createWeight(searcher, ScoreMode.COMPLETE_NO_SCORES, 1.0f);
        weight.extractTerms(terms);

        Map<String, Integer> dfs = new HashMap<>();
        Map<String, Integer> tfs = new HashMap<>();

        for (Term t : terms) {
            String targ = t.text();
            int docFreq = searcher.getIndexReader().docFreq(t);
            if (docFreq == 0) {
                continue;
            }
            Integer i = new Integer(docFreq);
            dfs.put(targ, i);

            long tf = searcher.getIndexReader().totalTermFreq(t);
            tfs.put(targ, (int) tf);
        }

        SimpleTargetTermResults results = new SimpleTargetTermResults(dfs, tfs);

        return results;
    }

    /**
     * Simple utility method to get document counts for a given query.
     * This uses TotalHitCounter.
     *
     * @param query  query
     * @param reader reader
     * @return number of docs with a hit
     * @throws java.io.IOException if there is an exception from teh searcher
     */
    public int simpleDocCount(Query query, IndexReader reader) throws IOException {
        IndexSearcher searcher = new IndexSearcher(reader);
        TotalHitCountCollector collector = new TotalHitCountCollector();
        searcher.search(query, collector);
        return collector.getTotalHits();
    }
}