org.hibernate.search.demos.tweets.ServiceImpl.java Source code

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Here is the source code for org.hibernate.search.demos.tweets.ServiceImpl.java

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/*
 * Hibernate Search, full-text search for your domain model
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.search.demos.tweets;

import java.io.IOException;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.SortField;
import org.apache.lucene.search.SortedNumericSortField;
import org.hibernate.search.jpa.FullTextEntityManager;
import org.hibernate.search.jpa.FullTextQuery;
import org.hibernate.search.query.dsl.QueryBuilder;

/**
 * Example service
 */
public class ServiceImpl {

    /**
     * this should be injected before use.
     */
    public FullTextEntityManager fullTextEntityManager;
    private QueryBuilder tweetQueryBuilder;

    /**
     * creates a FullTextQuery for all tweets mentioning a specific word/technology in the message field.
     */
    public FullTextQuery messagesMentioning(String keyword) {
        Query query = getQueryBuilder().keyword().onField("message").matching(keyword).createQuery();
        FullTextQuery fullTextQuery = fullTextEntityManager.createFullTextQuery(query);
        return fullTextQuery;
    }

    /**
     * Searches for all tweets from a specific account. This is case-sensitive.
     */
    public FullTextQuery messagesBy(String name) {
        Query query = getQueryBuilder().keyword().onField("sender").matching(name).createQuery();
        FullTextQuery fullTextQuery = fullTextEntityManager.createFullTextQuery(query);
        return fullTextQuery;
    }

    /**
     * To search for all tweets, sorted in creation order (assuming the timestamp is correct).
     * @return
     */
    public FullTextQuery allTweetsSortedByTime() {
        Query query = getQueryBuilder().all().createQuery();
        FullTextQuery fullTextQuery = fullTextEntityManager.createFullTextQuery(query);
        fullTextQuery.setSort(new Sort(new SortedNumericSortField("timestamp", SortField.Type.LONG)));
        return fullTextQuery;
    }

    /**
     * This is the most complex case, and uses ScoredTerm to represent the return value.
     * I guess this is a practical way to make a tag cloud out of all indexed terms.
     * @param inField Will return only scoredTerms in the specified field
     * @param minimumFrequency a minimum threshold, can be used to reduce not very significant words (see analyzers and stopwords for better results).
     * @throws IOException
    Set<ScoredTerm> mostFrequentlyUsedTerms(String inField, int minimumFrequency) throws IOException {
       String internedFieldName = inField.intern();
       SearchFactory searchFactory = fullTextEntityManager.getSearchFactory();
       IndexReader indexReader = searchFactory.getIndexReaderAccessor().open( Tweet.class );
       TreeSet<ScoredTerm> sortedTerms = new TreeSet<ScoredTerm>();
       try {
     TermEnum termEnum = indexReader.terms();
     while ( termEnum.next() ) {
        Term term = termEnum.term();
        if ( internedFieldName != term.field() ) {
           continue;
        }
        int docFreq = termEnum.docFreq();
        if ( docFreq < minimumFrequency ) {
           continue;
        }
        String text = term.text();
        sortedTerms.add( new ScoredTerm( text, docFreq ) );
     }
       }
       finally {
     searchFactory.getIndexReaderAccessor().close( indexReader );
     indexReader.close();
       }
       return sortedTerms;
    }*/

    private QueryBuilder getQueryBuilder() {
        if (tweetQueryBuilder == null) {
            tweetQueryBuilder = fullTextEntityManager.getSearchFactory().buildQueryBuilder().forEntity(Tweet.class)
                    .get();
        }
        return tweetQueryBuilder;
    }

}