mainservlet.java

ejb克斯人随风俗

/* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 
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 - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
 
 - Redistribution in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in
   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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 OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
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 $Id: MainServlet.java,v 1.1 2004/04/15 03:44:06 yutayoshida Exp $ */

package com.sun.j2ee.blueprints.waf.controller.web;

import java.io.*;
import java.util.*;

// J2EE Imports
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.ServletConfig;

// WAF imports
import com.sun.j2ee.blueprints.waf.util.I18nUtil;
import com.sun.j2ee.blueprints.waf.util.JNDINames;
import com.sun.j2ee.blueprints.waf.controller.GeneralFailureException;
import com.sun.j2ee.blueprints.waf.controller.web.util.WebKeys;
import com.sun.j2ee.blueprints.util.tracer.Debug;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.*;


public class MainServlet extends HttpServlet {
    
    private ServletContext context;
    private HashMap urlMappings;
    private HashMap eventMappings;
    private Locale defaultLocale = null;

    private RequestProcessor requestProcessor;
    private ScreenFlowManager screenFlowManager;
    
    public void init(ServletConfig config) throws ServletException {
        String defaultLocaleString = config.getInitParameter("default_locale");
        defaultLocale = I18nUtil.getLocaleFromString(defaultLocaleString);
        this.context = config.getServletContext();
        // these will have been initialized by the ApplicationComponentManager
        eventMappings = (HashMap)context.getAttribute(WebKeys.EVENT_MAPPINGS);
        urlMappings = (HashMap)context.getAttribute(WebKeys.URL_MAPPINGS);
        requestProcessor = (RequestProcessor)context.getAttribute(WebKeys.REQUEST_PROCESSOR);
        screenFlowManager = (ScreenFlowManager)context.getAttribute(WebKeys.SCREEN_FLOW_MANAGER);
    }
   
     public  void doGet(HttpServletRequest request, HttpServletResponse  response)
        throws IOException, ServletException {
        doProcess(request, response);
    }

    public  void doPost(HttpServletRequest request, HttpServletResponse  response)
        throws IOException, ServletException {
        doProcess(request, response);
        
    }
    
    private void doProcess(HttpServletRequest request, HttpServletResponse response)
                   throws IOException, ServletException {
        // set the locale of the user to default if not set
        if (request.getSession().getAttribute(WebKeys.LOCALE) == null) {
            request.getSession().setAttribute(WebKeys.LOCALE, defaultLocale);
        }
        try {
            String fullURL = request.getRequestURI();
            // get the screen name
            String selectedURL = null;            
            int lastPathSeparator = fullURL.lastIndexOf("/") + 1;
            if (lastPathSeparator != -1) {
                selectedURL = fullURL.substring(lastPathSeparator, fullURL.length());
            }
            URLMapping urlMapping = getURLMapping(selectedURL);
            
           // now check if the URI uses a transaction
            if (urlMapping.isTransactional()) {
                // start the transaction
                boolean tx_started = false;
                UserTransaction ut = null;
                try {
                    // Lookup the UserTransaction object
                    InitialContext ic = new InitialContext();
                    ut = (UserTransaction) ic.lookup("java:comp/UserTransaction");
                    ut.begin();   // start the transaction. 
                    tx_started = true;
                } catch (NamingException ne) {
                    // it should not have happened, but it is a recoverable error. 
                    // Just dont start the transaction. 
                    ne.printStackTrace();
                } catch (NotSupportedException nse) {
                    // Again this is a recoverable error. 
                    nse.printStackTrace();
                } catch (SystemException se) {
                    // Again this is a recoverable error. 
                    se.printStackTrace();
                }
                try {
                    requestProcessor.processRequest(urlMapping, request);
                    screenFlowManager.forwardToNextScreen(request,response);
                } finally {
                    // commit the transaction if it was started earlier successfully. 
                    try {
                        if (tx_started && ut != null) {
                            ut.commit();
                        }
                    } catch (IllegalStateException re) {
                        re.printStackTrace();
                    } catch (RollbackException re) {
                        re.printStackTrace();
                    } catch (HeuristicMixedException hme) {
                        hme.printStackTrace();
                    } catch (HeuristicRollbackException hre) {
                        hre.printStackTrace();
                    } catch (SystemException se) {
                        se.printStackTrace();
                    }
                }
            } else {
                    requestProcessor.processRequest(urlMapping, request);
                    screenFlowManager.forwardToNextScreen(request,response);
            }
        } catch (Throwable ex) {
            String className = ex.getClass().getName();
            String nextScreen = screenFlowManager.getExceptionScreen(ex);
            // put the exception in the request
            request.setAttribute(WebKeys.WAF_EXCEPTION, ex);
            if (nextScreen == null) {
                // send to general error screen
                ex.printStackTrace();
                throw new ServletException("MainServlet: unknown exception: " + className);
            }
            context.getRequestDispatcher(nextScreen).forward(request, response);
      }
    }
    
    /**
     * The UrlMapping object contains information that will match
     * a url to a mapping object that contains information about
     * the current screen, the Action that is needed to
     * process a request, and the Action that is needed
     * to insure that the propper screen is displayed.
    */
    private URLMapping getURLMapping(String urlPattern) {
        if ((urlMappings != null) && urlMappings.containsKey(urlPattern)) {
            return (URLMapping)urlMappings.get(urlPattern);
        } else {
            return null;
        }
    }
}