de.spieleck.pcs.http
Class ControllerServlet

java.lang.Object
  |
  +--javax.servlet.GenericServlet
        |
        +--javax.servlet.http.HttpServlet
              |
              +--de.spieleck.pcs.http.ControllerServlet

All Implemented Interfaces:

ConfigUser, Constants, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public class ControllerServlet

extends javax.servlet.http.HttpServlet

implements ConfigUser, Constants

This servlet acts as a Controller defined by the Front Controller Pattern. The ControllerServlet is the main gateway of a pcs based web application and every request should use this servlet.
The ControllerServlet uses a file to lookup the mappings between action keys and the implementing Action classes. This file is a Java Properties file specified by the servlet init parameter "pcsfw.controller.actions". If this is not set, "/conf/actions.properties" will be used instead.
If a init parameter "pcsfw.controller.viewconfig" is specified, this file name will be used to configure the used View

See Also:

Serialized Form

Field Summary

protected ControllerConfig	controllerConfig
protected static java.lang.String	description

Fields inherited from interface de.spieleck.pcs.Constants

ACTION_RESULT_XSL_FILE, CONTEXT_REAL_PATH, CONTOLLER_XML_CONFIG_PARAM, CONTROLLER_SESSION_EXCEPTION_PARAM_NAME, EXCEPTION_SERVICE_NAME, REQUEST_PATH_PARAM, REQUEST_SERVICE_NAME_PARAM, SESSION_AS_PARAMETER_NAME

Constructor Summary

ControllerServlet()

Method Summary

protected boolean	checkAuthorization(javax.servlet.http.HttpServletRequest request) by this method the Controller Servlet checks, if a given request is authorized or not.
void	destroy() Destroys the servlet.
protected void	display(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, ActionResult ar, ServiceInfo service)
protected void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Handles the HTTP GET method by calling processRequest
protected void	doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Handles the HTTP POST method by calling processRequest
protected ServiceInfo	getService(javax.servlet.http.HttpServletRequest request) returns an Action matching the given request.
java.lang.String	getServletInfo() Returns a short description of the servlet.
protected void	handleException(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.Exception e) This method handles exceptions by addind the exception to the session and call processRequest.
void	init(javax.servlet.ServletConfig config) Initializes the servlet.
protected void	processRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Processes requests for both HTTP GET and POST methods.
void	resetConfig() resets the configuration by calling the Servlet's init method

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

description

protected static java.lang.String description

controllerConfig

protected ControllerConfig controllerConfig

Constructor Detail

ControllerServlet

public ControllerServlet()

Method Detail

init

public void init(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException

Initializes the servlet.

Overrides:

init in class javax.servlet.GenericServlet

destroy

public void destroy()

Destroys the servlet.

Overrides:

destroy in class javax.servlet.GenericServlet

getService

protected ServiceInfo getService(javax.servlet.http.HttpServletRequest request)
                          throws ControllerException

returns an Action matching the given request. To determine the key of the action, at first the path is checked and as key is taken the string from the beginning of the path to the second occurance of '/'. As example if a request is processed with the URL "http://www.server.com/controller/action/" then the String "action" is used as key. If the ActionFactory returns no Action object for this key, the Controller checks whether there is a request parameter named "action". If such a parameter is found the Controller tries to get an Action from the ActionFactory with such a key. If this fails, the Controller tries to get an Action from the ActionFactory with the key "default". If again no matching action can be found, a ServletException is thrown.

Parameters:

request - the request to the Servlet

Returns:

a matching action

Throws:

javax.servlet.ServletException - if no matching action could be found

processRequest

protected void processRequest(javax.servlet.http.HttpServletRequest request,
                              javax.servlet.http.HttpServletResponse response)
                       throws javax.servlet.ServletException,
                              java.io.IOException

Processes requests for both HTTP GET and POST methods. It gets an action via the getAction-Method and performs this action with all parameters supplied by the request and the request and the response. The request is put in the hashtable of the action with the key "request" and the reponse is put with the key "response".

Parameters:

request - servlet request

response - servlet response

display

protected void display(javax.servlet.http.HttpServletRequest request,
                       javax.servlet.http.HttpServletResponse response,
                       ActionResult ar,
                       ServiceInfo service)
                throws java.io.IOException

handleException

protected void handleException(javax.servlet.http.HttpServletRequest request,
                               javax.servlet.http.HttpServletResponse response,
                               java.lang.Exception e)
                        throws java.io.IOException,
                               javax.servlet.ServletException

This method handles exceptions by addind the exception to the session and call processRequest. Then the called method will display the exception.

checkAuthorization

protected boolean checkAuthorization(javax.servlet.http.HttpServletRequest request)

by this method the Controller Servlet checks, if a given request is authorized or not. Should be overwritten if neccessary, since this implementaiton allways returns true.

Parameters:

request - the request which is checked for authorization

doGet

protected void doGet(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response)
              throws javax.servlet.ServletException,
                     java.io.IOException

Handles the HTTP GET method by calling processRequest

Overrides:

doGet in class javax.servlet.http.HttpServlet

Parameters:

request - servlet request

response - servlet response

doPost

protected void doPost(javax.servlet.http.HttpServletRequest request,
                      javax.servlet.http.HttpServletResponse response)
               throws javax.servlet.ServletException,
                      java.io.IOException

Handles the HTTP POST method by calling processRequest

Overrides:

doPost in class javax.servlet.http.HttpServlet

Parameters:

request - servlet request

response - servlet response

getServletInfo

public java.lang.String getServletInfo()

Returns a short description of the servlet.

Overrides:

getServletInfo in class javax.servlet.GenericServlet

resetConfig

public void resetConfig()

resets the configuration by calling the Servlet's init method

Specified by:

resetConfig in interface ConfigUser