《jsp网站开发技术》中的源代码(清华大学出版社)

				/*
				 * Copyright (c) 2000 Javacat. All Rights Reserved.
				 *
				 * @(#)Cart.java 12/10/2000
				 */
				
				package com.javacat.jsp.beans.ebiz;
				
				import javax.servlet.http.*;
				import java.util.Vector;
				import java.util.Enumeration;
				/**
				*The Cart bean is used as a dummy cart for client
				*to hold their goods when they're shopping online.
				*/
				public class Cart{
				    Vector goods= new Vector();
				
				    String submit = null;
				    int ablumID = -1;
				    String item=null;
				    //add new goods
				    private void add(String id) {
				    if(!goods.contains(id))
					    goods.addElement(id);
				    }
				    //remove the specified goods
				    private void remove(String[] ids) {
				     for(int i=0;i					       goods.removeElement(ids[i]);
				     }
				    }
				
				    public void setItem(String id) {
					item = id;
				    }
				
				    public void setSubmit(String s) {
				    if(s==null||s.equals(""))
				      return;
				    else submit=s;
				    }
				
				    public String[] getAllGoods() {
					String[] sg = new String[goods.size()];
					goods.copyInto(sg);
					return sg;
				    }
				
				    public void processRequest(HttpServletRequest request) {
					// null value for submit - user hit enter instead of clicking on
					// "add" or "remove"
					if (submit == null&&request.getParameter("remove")==null){
					    reset();
				      return;
				  }
					if (submit.equals("add")){
					    add(item);
				      this.setAlbumID(item);
				  }
					else if (request.getParameter("remove")!=null){
				      java.util.Enumeration pns=request.getParameterNames();
					    String pn;
					    String p;
				      Vector vid=new Vector();
					    while(pns.hasMoreElements()){
						    pn=(String)pns.nextElement();
						    p=request.getParameter(pn);
				        if(pn.startsWith("c")&&p.equals("on")){
				          vid.add(pn.substring(1));
				        }
				      }
				      if(vid.size()>0){
				      String[] ids=new String[vid.size()];
				      vid.copyInto(ids);
					    remove(ids);
				      }
				  }
					// reset at the end of the request
					reset();
				    }
				
				    // reset
				    private void reset() {
					submit = null;
					item = null;
				    }
				    public synchronized void setAlbumID(String ite)
				    {
				      this.ablumID=Integer.parseInt(ite);
				    }
				    public synchronized int getAlbumID()
				    {
				      return this.ablumID;
				    }
				    public Album[] getOrderedAlbums()
				    {
				      String[] items=this.getAllGoods();
				      Album[] albums=new Album[items.length];
				      for(int i=0;i				      {
				        albums[i]=new Album(Integer.parseInt(items[i]));
				      }
				      return albums;
				    }
				}