ch5.postServlet
Class ControllerHelper

java.lang.Object
  shared.HelperBaseCh4
      shared.HelperBaseCh5
          ch5.postServlet.ControllerHelper

public class ControllerHelper
extends HelperBaseCh5

Contains doGet and doPost methods.

This is the same as the helper for the persistentData controller, with the addition of a doPost method.

The Get and Post requests are handled differently.

• Get requests are treated as initial requests. Old data in the session is ignored and the default button method is called.
• Post requests are treated as continuations of a request. Old data is retrieved from the session and the correct method for the button is executed.

Nested Class Summary

Nested classes/interfaces inherited from class shared.HelperBaseCh4

HelperBaseCh4.SessionData

Field Summary

Fields inherited from class shared.HelperBaseCh4

logger, request, response

Constructor Summary

ControllerHelper(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
Call the base class constructor to store the request and response.

Method Summary

java.lang.String	confirmMethod() The method to call when the confirm button is clicked.
void	copyFromSession(java.lang.Object sessionHelper) The implementation of the abstract method from the helper base.
protected void	doGet() GET is considered a new request, so the old data is not read and the JSP is always for the edit page.
protected void	doPost() POST is considered a continuation of a previous request, so read the old data from the session and calculate the next page based on the button.
java.lang.String	editMethod() The method to call when the edit button is clicked.
java.lang.Object	getData() An accessor that allows the JSPs to retrieve the bean from the helper.
protected java.lang.String	jspLocation(java.lang.String page) Encapsulates the location of the JSPs.
java.lang.String	processMethod() The method to call when the process button is clicked.

Methods inherited from class shared.HelperBaseCh5

getErrors, isValid, isValidProperty, setErrors

Methods inherited from class shared.HelperBaseCh4

addHelperToSession, addHelperToSession, executeButtonMethod, executeButtonMethod, fillBeanFromRequest, invokeButtonMethod, writeError

Methods inherited from class java.lang.Object

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

Constructor Detail

ControllerHelper

public ControllerHelper(javax.servlet.http.HttpServletRequest request,
                        javax.servlet.http.HttpServletResponse response)

Call the base class constructor to store the request and response.

Parameters:

request - Request information encapsulated in a Java object

response - Response information encapsulated in a Java object

Method Detail

getData

public java.lang.Object getData()

An accessor that allows the JSPs to retrieve the bean from the helper.

Returns:

The bean that contains the data from the request.

copyFromSession

public void copyFromSession(java.lang.Object sessionHelper)

The implementation of the abstract method from the helper base.

The method copies data from the old helper that is still in the session to the current helper.

Specified by:

copyFromSession in class HelperBaseCh4

Parameters:

sessionHelper - The old helper that is still in the session.

jspLocation

protected java.lang.String jspLocation(java.lang.String page)

Encapsulates the location of the JSPs.

Parameters:

page - The file name of the JSP.

Returns:

The full path to the JSP.

editMethod

public java.lang.String editMethod()

The method to call when the edit button is clicked.

The method does nothing else at this time than indicate the address of the page.

The method is adorned with a ButtonMethod annotation that associates the name of a button with the method.

Returns:

The address for the JSP.

confirmMethod

public java.lang.String confirmMethod()

The method to call when the confirm button is clicked.

Use the fillBeanFromRequest method to automatically copy the request data into the bean and implement required validation.

The method is adorned with a ButtonMethod annotation that associates the name of a button with the method.

Returns:

The address for the JSP.

processMethod

public java.lang.String processMethod()

The method to call when the process button is clicked.

The method does nothing else at this time than indicate the address of the page.

The method is adorned with a ButtonMethod annotation that associates the name of a button with the method.

Returns:

The address for the JSP.

doGet

protected void doGet()
              throws javax.servlet.ServletException,
                     java.io.IOException

GET is considered a new request, so the old data is not read and the JSP is always for the edit page.

1. Add the helper to the session but ignore the data from the old helper in the session
2. Always go to the edit page
3. Forward the request and response to the next address.

Overrides:

doGet in class HelperBaseCh4

Throws:

javax.servlet.ServletException

java.io.IOException

doPost

protected void doPost()
               throws javax.servlet.ServletException,
                      java.io.IOException

POST is considered a continuation of a previous request, so read the old data from the session and calculate the next page based on the button.

1. Add the helper to the session and copy the old helper data into the current helper. This eliminates the need for hidden fields.
2. Call the appropriate method for the clicked button. This is done from a method in the helper base that loops throuh all the button methods, looking for the one for the clicked button. This eliminates the need for the nested if-else block.
3. Forward the request and response to the next address.

Overrides:

doPost in class HelperBaseCh4

Throws:

javax.servlet.ServletException

java.io.IOException