peer instruction persistence context

JPAUtil.java

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;


/**
 *
 * @author natan
 */
public class JPAUtil {
    private static final EntityManagerFactory EMF = Persistence.createEntityManagerFactory("default");
    
    public static EntityManager getEntityManager() {
        return EMF.createEntityManager();
    }
    
    public static void closeEntityManager() {
        EMF.close();
    }
}

PersistencePerson.java

import com.natansevero.peer.instruction.entities.Person;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;

/**
 *
 * @author natan
 */
public class PersistencePerson {
    private final EntityManager em;
    
    public PersistencePerson() {
        em = JPAUtil.getEntityManager();
    }
    
    public Person add(Person p) {
        EntityTransaction tx = em.getTransaction();
        tx.begin();
        em.persist(p);
        tx.commit();
        
        return p;
    }
    
    public Person update(Person p) {
        EntityTransaction tx = em.getTransaction();
        tx.begin();
        em.merge(p);
        tx.commit();
        
        return p;
    }
    
    public Person delete(Person p) {
        EntityTransaction tx = em.getTransaction();
        tx.begin();
        em.remove(p);
        tx.commit();
        
        return p;
    }
    
    public void listAll() {
        Query q = em.createQuery("select p from Person p", Person.class);
 
        List<Person> persons = q.getResultList();
        
        for(Person p : persons) System.out.println(p.toString()); 
    }

}

Person.java

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

/**
 *
 * @author natan
 */
@Entity
public class Person implements Serializable {
    @Id
    @GeneratedValue
    private Integer id;
    
    @Column
    private String name;
    
    public Person() {
        
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Person{" + "id=" + id + ", name=" + name + '}';
    }
    
    
}