TFIDFCalculatorImpl.java

/*   Copyright 2012 Tim Garrett, Mothsoft LLC
 *
 *  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.
 */
package com.mothsoft.alexis.engine.textual;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.apache.log4j.Logger;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.hibernate.Session;
import org.hibernate.search.FullTextSession;
import org.hibernate.search.Search;
import org.hibernate.search.SearchFactory;
import org.hibernate.search.indexes.IndexReaderAccessor;
import org.springframework.transaction.annotation.Transactional;

import com.mothsoft.alexis.domain.Document;
import com.mothsoft.alexis.domain.DocumentAssociation;
import com.mothsoft.alexis.domain.DocumentTerm;
import com.mothsoft.alexis.domain.TFIDF;
import com.mothsoft.alexis.engine.Task;

/**
 * Calculate the TF-IDF and create dependent summary data
 * 
 * @author tgarrett
 * 
 */
public class TFIDFCalculatorImpl implements Task {

    private static final Logger logger = Logger.getLogger(TFIDFCalculatorImpl.class);

    private static final String CONTENT_TEXT_FIELD_NAME = "content.text";

    @PersistenceContext
    private EntityManager em;

    public TFIDFCalculatorImpl() throws IOException {
    }

    public void setEm(EntityManager em) {
        this.em = em;
    }

    @SuppressWarnings("unchecked")
    @Transactional
    public void execute() {
        final long start = System.currentTimeMillis();

        final FullTextSession fullTextSession = Search.getFullTextSession((Session) this.em.getDelegate());
        final SearchFactory searchFactory = fullTextSession.getSearchFactory();
        final IndexReaderAccessor ira = searchFactory.getIndexReaderAccessor();
        final IndexReader reader = ira.open(com.mothsoft.alexis.domain.Document.class);

        final Query query = em
                .createQuery("select d from Document d join d.documentTerms dt where dt.tfIdf IS NULL ORDER BY d.id ASC");
        final List<Document> documents = query.getResultList();

        final Term luceneTerm = new Term(CONTENT_TEXT_FIELD_NAME);
        int affectedRows = 0;

        try {
            for (final Document document : documents) {
                final Map<String, Float> termTfIdfMap = new HashMap<String, Float>();

                // calculate term TF-IDFs
                for (final DocumentTerm documentTerm : document.getDocumentTerms()) {
                    final Term term = luceneTerm.createTerm(documentTerm.getTerm().getValueLowercase());
                    Float score = TFIDF.score(documentTerm.getTerm().getValueLowercase(), documentTerm.getCount(),
                            document.getTermCount(), reader.numDocs(), reader.docFreq(term));
                    documentTerm.setTfIdf(score);
                    termTfIdfMap.put(documentTerm.getTerm().getValueLowercase(), score);
                    affectedRows++;
                }

                // update association weights
                for (final DocumentAssociation documentAssociation : document.getDocumentAssociations()) {
                    final String a = documentAssociation.getA().getValueLowercase();
                    final String b = documentAssociation.getB().getValueLowercase();
                    documentAssociation.setAssociationWeight((float) documentAssociation.getAssociationCount()
                            * (termTfIdfMap.get(a) + termTfIdfMap.get(b)));
                }
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            ira.close(reader);
        }

        logger.info("TF-IDF calc took: " + ((System.currentTimeMillis() - start) / 1000.00) + " seconds and affected "
                + affectedRows + " rows.");
    }

}