ReverseIlikeExpression.java

/**
 * Copyright 2010 CosmoCode GmbH
 *
 * 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 de.cosmocode.hibernate;

import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.criterion.CriteriaQuery;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.IlikeExpression;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.PostgreSQLDialect;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.engine.TypedValue;

/**
 * A version of the {@link IlikeExpression} which uses
 * the property as the pattern.
 * 
 * <p>
 *   A normal {@link IlikeExpression} renders ilike expressions
 *   like this:
 *   <pre>
 *     lower(my_column) like ?
 *   </pre>
 *   This implementation produces the following:
 *   <pre>
 *     ? like lower(concat('%', my_column))
 *   </pre>
 * </p>
 *
 * @author Willi Schoenborn
 */
public class ReverseIlikeExpression implements Criterion {

    private static final long serialVersionUID = -7965682008508199091L;
    
    private final String propertyName;
    private final Object value;
    private final PropertyMatchMode matchMode;

    protected ReverseIlikeExpression(String propertyName, String value, PropertyMatchMode matchMode) {
        this.propertyName = propertyName;
        this.value = value;
        this.matchMode = matchMode;
    }

    @Override
    public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
        final SessionFactoryImplementor factory = criteriaQuery.getFactory();
        final Dialect dialect = factory.getDialect();
        final String[] columns = criteriaQuery.getColumnsUsingProjection(criteria, propertyName);
        
        if (columns.length != 1) throw new HibernateException("ilike may only be used with single-column properties");
        
        final String columnName = columns[0];
        final String s = matchMode.toMatchString(factory, columnName);
        
        if (dialect instanceof PostgreSQLDialect) {
            return "? ilike " + s;
        } else {
            return "? like " + dialect.getLowercaseFunction() + "(" + s + ")";
        }
        
    }

    @Override
    public TypedValue[] getTypedValues(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
        return new TypedValue[] {criteriaQuery.getTypedValue(criteria, propertyName, value.toString().toLowerCase())};
    }

    @Override
    public String toString() {
        return value + " ilike " + propertyName;
    }
    
}