Repository.java

package example.bdutra.jpa;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.transaction.Transactional;

@Transactional
public class Repository<T> {

	@PersistenceContext(unitName = "ArquillianPU")
	public EntityManager em;
	
	private Class<T> entityClass;

	public Repository() {
	}

	public Repository(Class<T> entityClass) {
		this.entityClass = entityClass;
	}

	public void create(T entity) {
		em.persist(entity);
	}

	public void update(T entity) {
		em.merge(entity);
	}

	public void delete(Long id) {
		T entity = em.find(entityClass, id);
		if (entity != null) {
			em.remove(entity);
		}
	}

	public void delete(T entity) {
		em.remove(entity);
	}

	public T find(Long id) {
		return em.find(entityClass, id);
	}

	@SuppressWarnings("unchecked")
	public List<T> findAll() {
		return em.createQuery("select t from " + entityClass.getSimpleName() + " t").getResultList();
	}

}