GenericDaoHibernate.java

/*******************************************************************************
 *   Gisgraphy Project 
 * 
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 * 
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *   Lesser General Public License for more details.
 * 
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
 * 
 *  Copyright 2008  Gisgraphy project 
 *  David Masclet <davidmasclet@gisgraphy.com>
 *  
 *  
 *******************************************************************************/
package com.gisgraphy.dao.hibernate;

import java.io.Serializable;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.gisgraphy.dao.GenericDao;

/**
 * This class serves as the Base class for all other DAOs - namely to hold
 * common CRUD methods that they might all use. You should only need to extend
 * this class when your require custom CRUD logic.
 * <p>
 * To register this class in your Spring context file, use the following XML.
 * 
 * <pre>
 *      <bean id="fooDao" class="com.gisgraphy.dao.hibernate.GenericDaoHibernate">
 *          <constructor-arg value="com.gisgraphy.model.Foo"/>
 *          <property name="sessionFactory" ref="sessionFactory"/>
 *      </bean>
 * </pre>
 * 
 * @author <a href="mailto:bwnoll@gmail.com">Bryan Noll</a>
 * @param <T>
 *                a type variable
 * @param <PK>
 *                the primary key for that type
 */
public class GenericDaoHibernate<T, PK extends Serializable> extends
	HibernateDaoSupport implements GenericDao<T, PK> {
    /**
     * Log variable for all child classes. Uses LogFactory.getLog(getClass())
     * from Commons Logging
     */
    protected final Log log = LogFactory.getLog(getClass());

    private Class<T> persistentClass;

    /**
     * Constructor that takes in a class to see which type of entity to persist
     * 
     * @param persistentClass
     *                the class type you'd like to persist
     */
    public GenericDaoHibernate(final Class<T> persistentClass) {
	this.persistentClass = persistentClass;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public List<T> getAll() {
	return super.getHibernateTemplate().loadAll(this.persistentClass);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public T get(PK id) {
	T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
		id);

	if (entity == null) {
	    log.warn("Uh oh, '" + this.persistentClass + "' object with id '"
		    + id + "' not found...");
	    throw new ObjectRetrievalFailureException(this.persistentClass, id);
	}

	return entity;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public boolean exists(PK id) {
	T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
		id);
	return entity != null;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public T save(T object) {
	return (T) super.getHibernateTemplate().merge(object);
    }

    /**
     * {@inheritDoc}
     */
    public void remove(PK id) {
	super.getHibernateTemplate().delete(this.get(id));
    }
}