InventoryMgmtEJB.java

package ejava.examples.ejbwar.inventory.ejb;

import java.util.List;
import java.util.UUID;

import javax.ejb.Stateless;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;
import javax.inject.Inject;
import javax.persistence.EntityManager;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import ejava.examples.ejbwar.inventory.bo.Categories;
import ejava.examples.ejbwar.inventory.bo.Category;
import ejava.examples.ejbwar.inventory.bo.Product;
import ejava.examples.ejbwar.inventory.bo.Products;
import ejava.examples.ejbwar.inventory.cdi.Inventory;
import ejava.examples.ejbwar.inventory.dao.InventoryDAO;

/**
 * This class implements the core transactional business logic for the 
 * inventory management. It is implemented as a no interface @Stateless
 * session bean and has JAX-RS and RMI facades that deal with technology-
 * specific communications with remote clients.
 */
@Stateless
public class InventoryMgmtEJB {
    private static final Logger logger = LoggerFactory.getLogger(InventoryMgmtEJB.class);
    
    @Inject
    private InventoryDAO dao;
    @Inject @Inventory
    private EntityManager em; //used for demo
    
    /**
     * Returns a list of categories that match the name provided
     * @param name
     * @return
     */
    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public Categories findCategoryByName(String name, int offset, int limit) {
        List<Category> categories = dao.findCategoryByName("%" + name + "%", offset, limit);
        for (Category category : categories) {
            category.setProductCount(categories.size());
            dao.detachCategory(category); //detach before manipulating collection 
            category.setProducts(null);
        }
        return new Categories(categories, 0, 0);
    }
    

    @TransactionAttribute(TransactionAttributeType.REQUIRED)
    public Category createOrGetCategory(String name) {
        List<Category> categories = dao.findCategoryByName(name, 0, 1); 
        if (categories.size()==0) {
            Category category=new Category(name);
            dao.createCategory(category);
            return category;
        }
        else {
            return categories.get(0);
        }
    }

    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public Category getCategory(int id) {
        return dao.getCategory(id);
    }

    @TransactionAttribute(TransactionAttributeType.REQUIRED)
    public void deleteCategory(int id) {
        Category category = dao.getCategory(id);
        if (category != null) {
            dao.deleteCategory(category);
        }
    }


    @TransactionAttribute(TransactionAttributeType.REQUIRED)
    public Product addProduct(Product product, String categoryName) {
        product.setProtectedValue(UUID.randomUUID().toString());
        dao.addProduct(product);
        Category category = createOrGetCategory(categoryName);
        category.getProducts().add(product);
        product = dao.getProduct(product.getId());
        return product;
    }
    
    @TransactionAttribute(TransactionAttributeType.REQUIRED)
    public Product updateProduct(Product product) {
        logger.info("updating existing product: {}", dao.getProduct(product.getId()));
        logger.info("to these values: {}", product);
        dao.updateProduct(product);
        em.flush();
        em.clear();
        Product dbResult = dao.getProduct(product.getId());
        logger.info("resulting product: {}", dbResult);
        return dbResult;
    }
    
    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public Products findProductByName(String name, int offset, int limit) {
        return new Products(dao.findProductsByName("%" + name + "%", offset, limit), offset, limit);
    }

    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public Product getProduct(int id) {
        return dao.getProduct(id);
    }

    @TransactionAttribute(TransactionAttributeType.REQUIRED)
    public void deleteProduct(Product product) {
        dao.deleteProduct(product);
    }
}