package org.jboss.tools.examples.DAO;

import java.util.List;
import java.util.logging.Logger;

import javax.inject.Inject;
import javax.persistence.EntityManager;

public abstract class DAO<T> {

	@Inject
	private Logger log;

	@Inject
	private EntityManager em;

	protected <T> T update(T entity) {
		return em.merge(entity);
	}

	protected <T> T create(T t) {
		return em.merge(t);
	}

	protected <T> void delete(T t) {
		em.remove(t);
	}

	protected <T> T readById(Class<T> pClass, int pId) {
		return em.find(pClass, pId);
	}

	public <T> List<T> queryFind(int maxResults, Class<T> clazz, String queryName, Object... parameters) {
		javax.persistence.Query q = em.createNamedQuery(queryName);
		if (parameters != null) {
			for (int i = 0; i < parameters.length; i++) {
				q.setParameter(i + 1, parameters[i]);
			}
		}
		q.setMaxResults(maxResults);
		return (List<T>) q.getResultList();
	}

	public <T> List<T> queryFind(Class<T> clazz, String queryName, Object... parameters) {
		return queryFind(Integer.MAX_VALUE, clazz, queryName, parameters);
	}

}