FileDocCategorySizeDatePackage
PBDispatcherServlet.javaAPI DocExample4467Thu Jun 28 16:14:16 BST 2001com.ora.jsp.servlets

PBDispatcherServlet

public class PBDispatcherServlet extends HttpServlet
This class acts as a controller for the Project Billboard example, dispatching to separate Action objects for request processing.
author
Hans Bergsten, Gefion software
version
1.0

Fields Summary
private Hashtable
actions
Constructors Summary
Methods Summary
public voiddestroy()
Removes the EmployeeRegistryBean and NewsBean servlet context attributes.

        getServletContext().removeAttribute("empReg");
        getServletContext().removeAttribute("news");
public voiddoGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
Performs the same processing as for a POST request.

        doPost(request, response);
public voiddoPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
Locates the Action object corresponding to the requested action, or the login Action in case the user is not yet authenticated, and dispatch the processing to the selected Action object.

        
        String actionName = request.getParameter("action");
        if (actionName == null) {
            response.sendError(HttpServletResponse.SC_NOT_ACCEPTABLE);
            return;
        }
        
        Action action = (Action) actions.get(actionName);
        if (action == null) {
            response.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            return;
        }
        
        // Use the login action if the user is not authenticated
        if (!isAuthenticated(request) && 
            !("authenticate".equals(actionName) || 
	      "logout".equals(actionName))) {
            action = (Action) actions.get("login");
        }
        action.perform(this, request, response);
public voidinit()
Creates the application scope objects used by the Actions and JSP pages in this application.

Note! In this example, a DataSource object is created using hardcoded information. In a real application, it should be retrieved through JNDI or created based on configurable information if JNDI is not used. If the application contains more than one servlet, it may also be better to do all initialization in a servlet dedicated to setting up the application environment instead.

        DataSource ds = null;
        try {
            ds = new DataSourceWrapper("sun.jdbc.odbc.JdbcOdbcDriver", 
                "jdbc:odbc:example", null, null);
        }
        catch (Exception e) {} // Ignore all in this example
        EmployeeRegistryBean empReg = new EmployeeRegistryBean();
        empReg.setDataSource(ds);
        getServletContext().setAttribute("empReg", empReg);

        NewsBean news = new NewsBean();
        getServletContext().setAttribute("news", news);
        initActions();
private voidinitActions()
Initializes the set of Action objects used by the application. Instead of hardcoding this list, it can be based on configuration information, such as servlet initialization parameters.

        actions = new Hashtable();
        actions.put("authenticate", new AuthenticateAction());
        actions.put("logout", new LogoutAction());
        actions.put("storeMsg", new StoreMsgAction());
        actions.put("updateProfile", new UpdateProfileAction());
        actions.put("showPage", new ShowPageAction());
        actions.put("login", new LoginAction());
private booleanisAuthenticated(javax.servlet.http.HttpServletRequest request)
Returns true if the session contains the authentication token.

        boolean isAuthenticated = false;
        HttpSession session = request.getSession();
        if (session.getAttribute("validUser") != null) {
            isAuthenticated = true;
        }
        return isAuthenticated;