001    /*
002     * Cumulus4j - Securing your data in the cloud - http://cumulus4j.org
003     * Copyright (C) 2011 NightLabs Consulting GmbH
004     *
005     * This program is free software: you can redistribute it and/or modify
006     * it under the terms of the GNU Affero General Public License as
007     * published by the Free Software Foundation, either version 3 of the
008     * License, or (at your option) any later version.
009     *
010     * This program is distributed in the hope that it will be useful,
011     * but WITHOUT ANY WARRANTY; without even the implied warranty of
012     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013     * GNU Affero General Public License for more details.
014     *
015     * You should have received a copy of the GNU Affero General Public License
016     * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017     */
018    package org.cumulus4j.store.query.eval;
019    
020    import java.util.Set;
021    
022    import org.cumulus4j.store.query.QueryEvaluator;
023    import org.datanucleus.query.expression.Literal;
024    
025    /**
026     * Evaluator representing literals.
027     *
028     * @author Marco หงุ่ยตระกูล-Schulze - marco at nightlabs dot de
029     */
030    public class LiteralEvaluator extends AbstractExpressionEvaluator<Literal>
031    {
032            public LiteralEvaluator(QueryEvaluator queryEvaluator, AbstractExpressionEvaluator<?> parent, Literal expression) {
033                    super(queryEvaluator, parent, expression);
034            }
035    
036            @Override
037            protected Set<Long> _queryResultDataEntryIDs(ResultDescriptor resultDescriptor)
038            {
039                    throw new UnsupportedOperationException("Cannot evaluate a literal alone!");
040            }
041    
042            public Object getLiteralValue()
043            {
044                    return getExpression().getLiteral();
045            }
046    }