orderfilter.java

《j2ee经典实例详解》的源代码。原书无附带光盘。介绍的是一个在线银行系统的例子。绝对难得

/*
 * Copyright (c) 2005 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2005 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */


package filters;

import java.io.*;
import java.sql.Timestamp;
import java.util.Iterator;
import javax.servlet.*;
import javax.servlet.http.*;
import database.BookDetails;
import cart.*;
import util.*;


public final class OrderFilter implements Filter {
    private FilterConfig filterConfig = null;

    public void init(FilterConfig filterConfig) throws ServletException {
        this.filterConfig = filterConfig;
    }

    public void destroy() {
        this.filterConfig = null;
    }

    public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
        if (filterConfig == null) {
            return;
        }

        // Render the generic servlet request properties
        StringWriter sw = new StringWriter();
        PrintWriter writer = new PrintWriter(sw);
        ServletContext context = filterConfig.getServletContext();
        Counter counter = (Counter) context.getAttribute("orderCounter");
        HttpServletRequest hsr = (HttpServletRequest) request;
        HttpSession session = hsr.getSession();
        ShoppingCart cart = (ShoppingCart) session.getAttribute("cart");
        Currency c = (Currency) session.getAttribute("currency");
        c.setAmount(cart.getTotal());
        writer.println();
        writer.println(
            "=======================================================");
        writer.println("The total number of orders is: " +
            counter.incCounter());
        writer.println("This order Received at " +
            (new Timestamp(System.currentTimeMillis())));
        writer.println();
        writer.print("Purchased by: " + request.getParameter("cardname"));
        writer.println();
        writer.print("Total: " + c.getFormat());
        writer.println();

        int num = cart.getNumberOfItems();

        if (num > 0) {
            Iterator i = cart.getItems()
                             .iterator();

            while (i.hasNext()) {
                ShoppingCartItem item = (ShoppingCartItem) i.next();
                BookDetails bookDetails = (BookDetails) item.getItem();
                writer.print("ISBN: " + bookDetails.getBookId());
                writer.print("   Title: " + bookDetails.getTitle());
                writer.print("   Quantity: " + item.getQuantity());
                writer.println();
            }
        }

        writer.println(
            "=======================================================");

        // Log the resulting string
        writer.flush();
        System.out.println(sw.getBuffer().toString());
        chain.doFilter(request, response);
    }

    public String toString() {
        if (filterConfig == null) {
            return ("OrderFilter()");
        }

        StringBuffer sb = new StringBuffer("OrderFilter(");
        sb.append(filterConfig);
        sb.append(")");

        return (sb.toString());
    }
}