bookstore.CategoryUtils.java Source code

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Here is the source code for bookstore.CategoryUtils.java

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package bookstore;

import bookstore.model.CategoryDAO;
import bookstore.model.ProductDAO;
import java.util.List;
import java.util.Set;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

/**
 *
 * @author abraham
 */
public class CategoryUtils {

    private static Session session;

    public static List<CategoryDAO> getCategories() {

        List<CategoryDAO> categories = null;

        session = HibernateUtil.getSessionFactory().openSession();

        Query query = session.createQuery("from CategoryDaoHibernate");
        categories = query.list();

        return categories;

    }

    public static CategoryDAO getCategoryById(int catId) {

        List<CategoryDAO> categories = null;

        session = HibernateUtil.getSessionFactory().openSession();

        Query query = session.createQuery("from CategoryDaoHibernate C where C.id = :ID");
        query.setParameter("ID", catId);

        categories = query.list();

        if (categories != null && !categories.isEmpty()) {
            return categories.get(0);
        }

        return null;
    }

    /**
     * 
     * @param category
     * @return the id of the new created category
     * 
     */
    public static int createCategory(CategoryDAO category) {

        int id = -1;

        session = HibernateUtil.getSessionFactory().openSession();
        Transaction tx = session.beginTransaction();
        id = (Integer) session.save(category);
        tx.commit();

        return id;

    }

    public static void addProductIntoCategory(ProductDAO product, int catid) {

        session = HibernateUtil.getSessionFactory().openSession();

        CategoryDAO category = getCategoryById(catid);
        product.setCategory(category);

        Set<ProductDAO> products = category.getProducts();
        products.add(product);
        category.setProducts(products);

        Transaction tx = session.beginTransaction();
        session.saveOrUpdate(category);
        tx.commit();

    }

    public static void deleteCategory(int catId) {

        session = HibernateUtil.getSessionFactory().openSession();

        Transaction tx = session.beginTransaction();
        String hql = "DELETE FROM CategoryDaoHibernate C WHERE C.id = :ID";
        Query query = session.createQuery(hql);
        query.setParameter("ID", catId);

        query.executeUpdate();
        tx.commit();

    }

}