NaturalIdCriterionBuilder.java

/*
 * The MIT License
 *
 * Copyright 2013 Jakub Jirutka <jakub@jirutka.cz>.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package cz.jirutka.rsql.hibernate;

import cz.jirutka.rsql.parser.model.Comparison;
import org.hibernate.HibernateException;
import org.hibernate.criterion.Criterion;
import org.hibernate.metadata.ClassMetadata;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Criterion Builder that can create <tt>Criterion</tt> for a property which
 * represents an association and argument which contains 
 * {@linkplain org.hibernate.annotations.NaturalId NaturalID} of the associated 
 * entity. It accepts only valid property of association type which associates
 * an entity that has a natural identifier.
 * 
 * @author Jakub Jirutka <jakub@jirutka.cz>
 */
public class NaturalIdCriterionBuilder extends IdentifierCriterionBuilder {
    
    private static final Logger LOG = LoggerFactory.getLogger(NaturalIdCriterionBuilder.class);

    
    @Override
    public boolean accept(String property, Class<?> entityClass, CriteriaBuilder builder) {
        return super.accept(property, entityClass, builder) 
                && hasNaturalIdentifier(property, entityClass, builder);
    }

    @Override
    public Criterion createCriterion(String property, Comparison operator, 
            String argument, Class<?> entityClass, String alias, CriteriaBuilder builder) 
            throws ArgumentFormatException, UnknownSelectorException {

        Class<?> type = findPropertyType(property, builder.getClassMetadata(entityClass));
        ClassMetadata classMetadata = builder.getClassMetadata(type);
        int[] idProps = classMetadata.getNaturalIdentifierProperties();
        Class<?> idType = classMetadata.getPropertyTypes()[idProps[0]].getReturnedClass();
        String idName = classMetadata.getPropertyNames()[idProps[0]];
        
        if (idProps.length != 1) {
            LOG.warn("Entity {} has more than one Natural ID, only first will be used");
        }
        LOG.debug("Entity {} has Natural ID {} of type {}", 
                new Object[]{type.getSimpleName(), idName, idType.getSimpleName()});

        Object castedArgument = builder.getArgumentParser().parse(argument, idType);
        
        String newAlias = builder.createAssociationAlias(alias + property);

        return createCriterion(newAlias +'.'+ idName, operator, castedArgument);

    }
    
    /**
     * Check if given property associates an entity that has a natural 
     * identifier. This doesn't check if property is an association type or even
     * if it exists!
     * 
     * @param property property name
     * @param builder parent <tt>CriteriaBuilder</tt>
     * @return <tt>true</tt> if given property associates an entity that has
     *         a natural identifier, <tt>false</tt> otherwise
     * @throws HibernateException If entity does not contain such property or
     *         it's not an association type.
     */
    protected boolean hasNaturalIdentifier(String property, Class<?> entityClass, CriteriaBuilder builder) 
            throws HibernateException {
        Class<?> type = findPropertyType(property, builder.getClassMetadata(entityClass));
        ClassMetadata assocClassMetadata = builder.getClassMetadata(type);
        
        return assocClassMetadata.hasNaturalIdentifier();
    }

}