GenericHibernateDAO.java

package fr.chantier.dao.impl;

import fr.chantier.dao.GenericDAO;
import org.hibernate.Criteria;
import org.hibernate.LockMode;
import org.hibernate.Session;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Order;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.util.List;
import java.util.HashSet;
import java.util.Collection;

/**
 * Implementation du dao generic.<br />
 * Ce dao sert de superClasse a tout les autres dao qui vont etre cree.
 * User: sora
 * Date: 2 oct. 2008
 * Time: 20:47:32
 */
public abstract class GenericHibernateDAO<T, ID extends Serializable>
        implements GenericDAO<T, ID> {

    private Class<T> persistentClass;
    private Session session;

    public GenericHibernateDAO(Session session) {
        this.persistentClass = (Class<T>) ((ParameterizedType) getClass()
                .getGenericSuperclass()).getActualTypeArguments()[0];
        this.session = session;
    }

    @SuppressWarnings("unchecked")
    public void setSession(Session s) {
        this.session = s;
    }

    protected Session getSession() {
        if (session == null)
            throw new IllegalStateException("Session has not been set on DAO before usage");
        return session;
    }

    public Class<T> getPersistentClass() {
        return persistentClass;
    }

    @SuppressWarnings("unchecked")
    public T findById(ID id, boolean lock) {
        T entity;
        if (lock)
            entity = (T) getSession().load(getPersistentClass(), id, LockMode.UPGRADE);
        else
            entity = (T) getSession().load(getPersistentClass(), id);

        return entity;
    }

    @SuppressWarnings("unchecked")
    public Collection<T> findAll() {
        return findByCriteria();
    }

    @SuppressWarnings("unchecked")
    public T makePersistent(T entity) {
        getSession().saveOrUpdate(entity);
        getSession().persist(entity);
        return entity;
    }

    public void makeTransient(T entity) {
        getSession().delete(entity);
    }

    public void flush() {
        getSession().flush();
    }

    public void clear() {
        getSession().clear();
    }

    /**
     * Use this inside subclasses as a convenience method.
     */
    @SuppressWarnings("unchecked")
    protected Collection<T> findByCriteria(Criterion... criterion) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        for (Criterion c : criterion) {
            crit.add(c);
        }
        return new HashSet(crit.list());
    }

}