ch4.enhanced
Class ControllerHelper

java.lang.Object
  shared.HelperBaseCh4
      ch4.enhanced.ControllerHelper

public class ControllerHelper
extends HelperBaseCh4

Helper that implements new features.

1. Eliminating hidden fields
2. Use a helper method to return the address for the JSPs
3. Automate filling the bean from the request
4. Automate translating a button name to a call to a method
5. The logger is implemented in the helper base class.

The base class has been moved to the shared package, since it contains member variables that use the same class for all controllers. The base class contains the request, response and logger variables.

This controller reuses the bean from Chapter 3, since no changes have been made to the bean.

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() The new template for the doGet method.
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.HelperBaseCh4

addHelperToSession, addHelperToSession, doPost, 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.

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

The new template for the doGet method.

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:

doGet in class HelperBaseCh4

Throws:

javax.servlet.ServletException

java.io.IOException