/*
* Hibernate OGM, Domain model persistence for NoSQL datastores
*
* 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.ogm.service.impl;
import java.util.List;
import java.util.Map;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.hql.QueryParser;
import org.hibernate.hql.ast.spi.EntityNamesResolver;
import org.hibernate.hql.lucene.LuceneProcessingChain;
import org.hibernate.hql.lucene.LuceneQueryParsingResult;
import org.hibernate.ogm.OgmSession;
import org.hibernate.ogm.util.impl.Log;
import org.hibernate.ogm.util.impl.LoggerFactory;
import org.hibernate.search.FullTextQuery;
import org.hibernate.search.FullTextSession;
import org.hibernate.search.ProjectionConstants;
import org.hibernate.search.Search;
import org.hibernate.search.engine.spi.SearchFactoryImplementor;
import org.hibernate.search.query.DatabaseRetrievalMethod;
import org.hibernate.search.query.ObjectLookupMethod;
/**
* QueryParserService using the ANTLR3-powered LuceneJPQLWalker.
* Expects the targeted entities and used attributes to be indexed via Hibernate Search,
* transforming HQL and JPQL in Lucene Queries.
*
* @author Sanne Grinovero <sanne@hibernate.org> (C) 2012 Red Hat Inc.
*/
public class LuceneBasedQueryParserService extends BaseQueryParserService {
private static final Log log = LoggerFactory.make();
private volatile SessionFactoryEntityNamesResolver entityNamesResolver;
public LuceneBasedQueryParserService() {
// TODO: make it possible to lookup the SearchFactoryImplementor at initialization time
// searchFactoryImplementor = lookupSearchFactory( registry );
}
@Override
public Query getParsedQueryExecutor(OgmSession session, String queryString, Map<String, Object> namedParameters) {
FullTextSession fullTextSession = Search.getFullTextSession( session );
LuceneQueryParsingResult parsingResult = new QueryParser().parseQuery( queryString,
createProcessingChain( session, unwrap( namedParameters ), fullTextSession ) );
log.createdQuery( queryString, parsingResult.getQuery() );
FullTextQuery fullTextQuery = fullTextSession.createFullTextQuery( parsingResult.getQuery(), parsingResult.getTargetEntity() );
if ( requiresProjections( parsingResult.getProjections() ) ) {
fullTextQuery.setProjection( parsingResult.getProjections().toArray( new String[parsingResult.getProjections().size()] ) );
}
fullTextQuery.setSort( parsingResult.getSort() );
// Following options are mandatory to load matching entities without using a query
// (chicken and egg problem)
fullTextQuery.initializeObjectsWith( ObjectLookupMethod.SKIP, DatabaseRetrievalMethod.FIND_BY_ID );
return fullTextQuery;
}
private boolean requiresProjections(List<String> projections) {
if ( projections.size() == 0 ) {
return false;
}
else if ( projections.size() == 1 && ProjectionConstants.THIS.equals( projections.get( 0 ) ) ) {
return false;
}
else {
return true;
}
}
private LuceneProcessingChain createProcessingChain(Session session, Map<String, Object> namedParameters, FullTextSession fullTextSession) {
EntityNamesResolver entityNamesResolver = getDefinedEntityNames( session.getSessionFactory() );
SearchFactoryImplementor searchFactory = (SearchFactoryImplementor) fullTextSession.getSearchFactory();
return new LuceneProcessingChain.Builder( searchFactory, entityNamesResolver )
.namedParameters( namedParameters )
.buildProcessingChainForClassBasedEntities();
}
private EntityNamesResolver getDefinedEntityNames(SessionFactory sessionFactory) {
if ( entityNamesResolver == null ) {
entityNamesResolver = new SessionFactoryEntityNamesResolver( sessionFactory );
}
return entityNamesResolver;
}
}