templateservlet.java

ejb克斯人随风俗

/* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 
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   the documentation and/or other materials provided with the
   distribution.
 
 Neither the name of Sun Microsystems, Inc. or the names of
 contributors may be used to endorse or promote products derived
 from this software without specific prior written permission.
 
 This software is provided "AS IS," without a warranty of any
 kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES
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 $Id: TemplateServlet.java,v 1.1 2004/04/15 03:44:14 yutayoshida Exp $ */

package com.sun.j2ee.blueprints.waf.view.template;

import java.io.IOException;
import java.net.URL;
import java.io.PrintWriter;
import java.util.Map;
import java.util.Iterator;
import java.util.StringTokenizer;
import java.util.HashMap;
import java.util.Locale;
import java.util.Enumeration;

// J2EE imports
import javax.servlet.*;
import javax.servlet.http.*;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.*;

import com.sun.j2ee.blueprints.waf.controller.web.util.WebKeys;

public class TemplateServlet extends HttpServlet {

    private HashMap allScreens;
    private ServletConfig config;
    private ServletContext context;
    private String defaultLocale;
    private boolean cachePreviousScreenAttributes = false;
    private boolean cachePreviousScreenParameters = false;
    private static final String PREVIOUS_SCREEN = "PREVIOUS";

    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        this.config = config;
        this.context = config.getServletContext();
        String cachePreviousScreenAttributesString = config.getInitParameter("cache_previous_screen_attributes");
        if (cachePreviousScreenAttributesString != null) {
            if (cachePreviousScreenAttributesString.toLowerCase().equals("true")) {
                System.out.println("TemplateServlet: Enabled caching of previous screen attributes.");
                cachePreviousScreenAttributes = true;
            }
        }
        // enable the caching of previous screen parameters
        String cachePreviousScreenParametersString = config.getInitParameter("cache_previous_screen_parameters");
        if (cachePreviousScreenParametersString != null) {
            if (cachePreviousScreenParametersString.toLowerCase().equals("true")) {
                System.out.println("TemplateServlet: Enabled caching of previous screen parameters.");
                cachePreviousScreenParameters = true;
            }
        }
        allScreens = new HashMap();
        defaultLocale = config.getInitParameter("default_locale");
        if (defaultLocale == null) {
            defaultLocale = (Locale.getDefault()).toString();
        }
        String locales = config.getInitParameter("locales");
        if (locales != null) {
            StringTokenizer strTok = new StringTokenizer(locales,",");
            while (strTok.hasMoreTokens()) {
                initScreens(config.getServletContext(), strTok.nextToken());
            }
        }
    }

    private void initScreens(ServletContext context, String language) {
        URL screenDefinitionURL = null;
        try {
            screenDefinitionURL = context.getResource("/WEB-INF/screendefinitions_" + language + ".xml");
        } catch (java.net.MalformedURLException ex) {
            System.err.println("TemplateServlet: malformed URL exception: " + ex);
        }
        if (screenDefinitionURL != null) {
            Screens screenDefinitions = ScreenDefinitionDAO.loadScreenDefinitions(screenDefinitionURL);
            if (screenDefinitions != null) {
                allScreens.put(language, screenDefinitions);
            } else {
                System.err.println("Template Servlet Error Loading Screen Definitions: Confirm that file at URL /WEB-INF/screendefinitions_" + language + ".xml contains the screen definitions");
            }
        } else {
            System.err.println("Template Servlet Error Loading Screen Definitions: URL /WEB-INF/screendefinitions_" + language + ".xml not found");
        }
    }

    public void doPost (HttpServletRequest request, 
      HttpServletResponse response)
        throws IOException, ServletException {
  process(request, response);
    }

    public void doGet (HttpServletRequest request, 
           HttpServletResponse  response)
        throws IOException, ServletException {
  process(request, response);
    }

    public void process (HttpServletRequest request, 
        HttpServletResponse  response)
        throws IOException, ServletException {

        String screenName = null;
        String localeString = null;
        String selectedUrl = request.getRequestURI();
        if (request.getSession().getAttribute(WebKeys.CURRENT_URL) != null) {
            request.getSession().removeAttribute(WebKeys.CURRENT_URL);
        }
        
        String languageParam = request.getParameter("locale");
        // The language when specified as a parameter overrides the language set in the session
        if (languageParam != null) {
            localeString = languageParam;
        } else if (request.getSession().getAttribute(WebKeys.LOCALE) != null) {
            localeString = ((Locale)request.getSession().getAttribute(WebKeys.LOCALE)).toString();
        }
        if (allScreens.get(localeString) == null) {
           localeString = defaultLocale;
        }
                
        // get the screen name
        int lastPathSeparator = selectedUrl.lastIndexOf("/") + 1;
        int lastDot = selectedUrl.lastIndexOf(".");
        if (lastPathSeparator != -1 && lastDot != -1 && lastDot > lastPathSeparator) {
            screenName = selectedUrl.substring(lastPathSeparator, lastDot);
        }
         // check if request is for the previous screen
        if (screenName.equals(PREVIOUS_SCREEN)) {
            String longScreenName  =  (String)request.getSession().getAttribute(WebKeys.PREVIOUS_SCREEN);
            int lastDot2 = longScreenName.lastIndexOf(".");
            if ( lastDot2 != -1 && lastDot2 > 0) {
                screenName = longScreenName.substring(0, lastDot2);
             }
            // put the request attributes stored in the session in the request
            if (cachePreviousScreenParameters) {
                Map previousParams = (Map)request.getSession().getAttribute(WebKeys.PREVIOUS_REQUEST_PARAMETERS);
                Map params = (Map)request.getParameterMap();
                Iterator it = previousParams.keySet().iterator();
                while (it.hasNext()) {
                    String key = (String)it.next();
                    Object value = previousParams.get(key);
                    params.put(key,value);
                }
            }
            // put in the previous request attributes
            if (cachePreviousScreenAttributes) {
                Map previousAttributes = (Map)request.getSession().getAttribute(WebKeys.PREVIOUS_REQUEST_ATTRIBUTES);
                Iterator it2 = previousAttributes.keySet().iterator();
                // put the request attributes stored in the session in the request
                while (it2.hasNext()) {
                    String key = (String)it2.next();
                    Object value = previousAttributes.get(key);
                    request.setAttribute(key,value);
                }
            }
        } else {
                  String extension = selectedUrl.substring(lastDot, selectedUrl.length());
                  request.getSession().setAttribute(WebKeys.PREVIOUS_SCREEN, screenName + extension);
                  if (cachePreviousScreenParameters) {
                      // copy all the parameters into a new map
                      HashMap newParams =  new HashMap();
                      Map params = (Map)request.getParameterMap();
                      Iterator it = params.keySet().iterator();
                     // put the request attributes stored in the session in the request
                     while (it.hasNext()) {
                         String key = (String)it.next();
                         Object value = params.get(key);
                         newParams.put(key,value);
                     }
                     request.getSession().setAttribute(WebKeys.PREVIOUS_REQUEST_PARAMETERS, newParams);
                  }
                  if (cachePreviousScreenAttributes) {
                     // put the request attributes into a map
                     HashMap attributes = new HashMap();
                     Enumeration enum = request.getAttributeNames();
                     while (enum.hasMoreElements()) {
                         String key = (String)enum.nextElement();
                         Object value = request.getAttribute(key);
                         attributes.put(key, value);
                     }
                     request.getSession().setAttribute(WebKeys.PREVIOUS_REQUEST_ATTRIBUTES, attributes);
                  }
        }                
        // get the screen information for the coresponding language
        Screen screen = null;
        if (screenName != null){
            Screens localeScreens = (Screens)allScreens.get(localeString);
            if (localeScreens != null) screen = (Screen)localeScreens.getScreen(screenName);
            // default to the default locale screen if it was not defined in the locale specific definitions
            if (screen == null) {
                System.err.println("Screen not Found loading default from " + defaultLocale);
                localeScreens = (Screens)allScreens.get(defaultLocale);
                screen = (Screen)localeScreens.getScreen(screenName);
            }
            if (screen != null) {
                request.setAttribute(WebKeys.CURRENT_SCREEN, screen);
                String templateName = localeScreens.getTemplate(screenName);
                if (templateName != null) {
                    context.getRequestDispatcher(templateName).forward(request, response);
                } else {
                    response.setContentType("text/html;charset=8859_1");
                    PrintWriter out = response.getWriter();
                    out.println("<font size=+4>Error:</font><br>Template file not found for " + screenName);
                }
            } else {
                response.setContentType("text/html;charset=8859_1");
                PrintWriter out = response.getWriter();
                out.println("<font size=+4>Error:</font><br>Definition for screen " + screenName + " not found");
            }
        }
    }
}