package ejbs;

import entities.Course;
import entities.Student;
import entities.Subject;

import javax.ejb.EJBException;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import java.util.List;

@Stateless(name = "SubjectEJB")
public class SubjectBean {
    @PersistenceContext
    EntityManager em;

    public void create(int code, String name,int courseCode,int courseYear,String scholarYear){
        try {
            Course course = (Course) em.find(Course.class,courseCode);
            if(course==null){
                return;
            }
            Subject subject = new Subject(code,name,course,courseYear,scholarYear);
            em.persist(subject);
            course.addSubject(subject);
        }catch (Exception e){
            throw new EJBException(e.getMessage());
        }
    }

    public List<Subject> all() {
        try {
            return (List<Subject>) em.createNamedQuery("getAllSubjects").getResultList();
        } catch (Exception e) {
            throw new EJBException("ERROR_RETRIEVING_SUBJECTS", e);
        }
    }
}