catalogbean.java

《Master EJB 第二版》

package examples;

import javax.ejb.*;
import java.rmi.RemoteException;
import java.util.*;
import javax.naming.*;
import javax.rmi.PortableRemoteObject;
/**
 * This catalog Stateless Session Bean retrieves a list of productitems.
 * ProductItem has product Id, name of the product and description
 */
public class CatalogBean implements SessionBean {
    
    /*
	 * Although this is a stateless session bean, we
	 * do have state - the session context.  Remember
	 * that stateless session beans can store state, they
	 * just can't store state on behalf of particular
	 * clients.
	 */
	private SessionContext ctx;
  	//----------------------------------------------------
	// End EJB-required methods
	//----------------------------------------------------
    
    /**
     * Returns the productitem for the given product id
     */
    public ProductItem getProductItem(String productId){
        try{
                Context ctx = new InitialContext();
                ProductHome productHome = (ProductHome)
                    PortableRemoteObject.narrow(
                        ctx.lookup("ProductHome"), ProductHome.class);
                Product product=productHome.findByPrimaryKey(productId);
                /*
                 * Creates and returns the productitem
                 */
                return new ProductItem(product.getProductID(),product.getName(),
                                product.getBasePrice(),product.getDescription());
            }catch (Exception e) {
                throw new EJBException(e);
            }
    }
    
    /**
     * Returns the list of productitems
     */
    public Vector getProductItemList(){
        try{
                Context ctx = new InitialContext();
                ProductHome productHome = (ProductHome)
                    PortableRemoteObject.narrow(
                            ctx.lookup("ProductHome"), ProductHome.class);
                Collection products=productHome.findAllProducts();
                Enumeration items = Collections.enumeration(products);
                Vector productItems=new Vector();
                    while (items.hasMoreElements()) {
                        Product product= (Product) items.nextElement();
                        /*
                         * Creates a new productitem
                         */
                        ProductItem p=new ProductItem(product.getProductID(),product.getName(),
                                        product.getBasePrice(),product.getDescription());
                        productItems.add(p);
                    }
                /*
                 * Returns the vector of product items
                 */
                return productItems;
            }catch (Exception e) {
                throw new EJBException(e);
            }
    }
        
    //----------------------------------------------------
	// Begin EJB-required methods.  The methods below are
	// called by the Container, and never called by client
	// code.
	//----------------------------------------------------
   
	public void ejbCreate() throws RemoteException {
		System.out.println("ejbCreate() called.");
	}
  
	public void ejbRemove() {
		System.out.println("ejbRemove() called.");
	}

	public void ejbActivate() {
		System.out.println("ejbActivate() called.");
	}

	public void ejbPassivate() {
		System.out.println("ejbPassivate() called.");
	}
   
    /**
	 * Associates this Bean instance with a particular
	 * context.
	 */
	public void setSessionContext(SessionContext ctx) {
		System.out.println("setSessionContext() called");
		this.ctx = ctx;
	}

}