orderwebimpl.java

一个优秀的供应商管理系统

package apusic.myshop.order.web;



/**
 * This class is the web-tier representation of the order.
 * It is used in the web tier to get an order that has been
 * placed. The requestId represents the order that has been
 * placed. If no order has been placed the requestId will
 * remain as -l.
 */

import java.rmi.RemoteException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import apusic.myshop.control.web.ModelManager;
import apusic.myshop.control.web.ModelUpdateListener;
import apusic.myshop.order.ejb.Order;
import apusic.myshop.util.WebKeys;
import apusic.myshop.order.model.OrderModel;
import apusic.myshop.util.Debug;
import apusic.myshop.control.GeneralFailureException;

public class OrderWebImpl extends OrderModel
    implements ModelUpdateListener {

    private ModelManager mm;
    private Order orderEjb;
    private HttpSession session;
    private int requestId = -1;

    public OrderWebImpl() {
	    super();
    }

    public void init(HttpServletRequest request){
        this.session = request.getSession();
        Integer id = (Integer)request.getAttribute(WebKeys.RequestIdKey);
        if (id != null) requestId = id.intValue();
        this.mm = (ModelManager)session.getAttribute("modelManager");
        syncUpData();
    }

    private void syncUpData() {
	    // Get data from the EJB
	    if (orderEjb == null && requestId != -1) {
	      orderEjb = mm.getOrderEJB(requestId);
	    }

	    // Using XOR to assert that either requestId == -1 or EJB is  non null.
	    Debug.assert((requestId == -1) ^ (orderEjb != null));
	    try {
	      if (orderEjb != null)
		      copy(orderEjb.getDetails());
      } catch (RemoteException re) {
	        throw new GeneralFailureException(re);
      }
    }

    public void performUpdate(){
        // do nothing - this is a request scope bean
    }
}