creating a framework that provide some crud boilerplate code.

EntityInstanceHandler.java

package org.jboss.saf;

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

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaQuery;

public class EntityInstanceHandler implements Serializable {

    @PersistenceContext
    EntityManager em;

    Object instance = null;

    public void saveOrUpdate(Object entity) {
         /*
         * verify which method should be used, merge, update or save
         */
    }

    public <T> T findById(Class<T> entityClass, Object primaryKey) {
        // could we keep a reference for object instance?
        return em.find(entityClass, primaryKey);

    }

    public <T> List<T> listAll(Class<T> entity) {
        CriteriaQuery<T> query = em.getCriteriaBuilder().createQuery(entity);
        query.from(entity);
        return em.createQuery(query).getResultList();
    }
    // we add some wrappers here. 
    public void remove(Object entity) {
        em.remove(entity);
    }

    public void delete(Object entity) {
        this.remove(entity);
    }

}

EntityService.java

@Model
@Stateful
public class EntityService implements Serializable {

    @Inject
    EntityInstanceHandler entityHandler;

    EntityExample entity = new EntityExample();

    public String saveEntityExample() {
        entityHandler.saveOrUpdate(entity);
        return "saflist.xhtml"; //I don't like returning string
    }

    public EntityExample getEntity() {
        return entity;
    }

    public void setEntity(EntityExample entity) {
        this.entity = entity;
    }

}