hirondelle.web4j.action
Class ActionTemplateShowAndApply

Object
  hirondelle.web4j.action.ActionImpl
      hirondelle.web4j.action.ActionTemplateShowAndApply

All Implemented Interfaces:

Action

public abstract class ActionTemplateShowAndApply
extends ActionImpl

Template for "first show, then validate and apply" groups of operations.

A good example is a page allowing the user to change their preferences : from the point of view of each user, there is only one set of user preferences. Often, a single form can be used to allow editing of preferences. Here, there is no listing of multiple items.

There are two operations in such cases :

• show me the form with the current data (if any)
• allow me to post my (validated) changes

Field Summary

static RequestParameter

SUPPORTED_OPERATION The operations supported by this template.

Fields inherited from class hirondelle.web4j.action.ActionImpl

DATA, ERRORS, ITEM_FOR_EDIT, ITEMS_FOR_LISTING, MESSAGES, USER_ID

Constructor Summary

protected

ActionTemplateShowAndApply(ResponsePage aForward, ResponsePage aRedirect, RequestParser aRequestParser) Constructor.

Method Summary

protected abstract void	apply() Validate the user input, and then apply an edit to the database.
ResponsePage	execute() Template method.
protected abstract void	show() Show the input form.
protected abstract void	validateUserInput() Validate items input by the user into a form.

Methods inherited from class hirondelle.web4j.action.ActionImpl

addError, addError, addError, addMessage, addMessage, addToRequest, addToSession, copyFromSessionToRequest, createSessionAndCsrfToken, endSession, getErrors, getExistingSession, getFromSession, getIdParam, getIdParams, getLocale, getLoggedInUserName, getMessages, getOperation, getOrderBy, getParam, getParamUnsafe, getRequestParser, getResponsePage, getTimeZone, getUserId, hasErrors, removeFromSession, setResponsePage

Methods inherited from class Object

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

Field Detail

SUPPORTED_OPERATION

public static final RequestParameter SUPPORTED_OPERATION

The operations supported by this template.

The supported operations are :

• Operation.Show
• Operation.Apply

The source of the Operation is described by ActionImpl.getOperation().

Constructor Detail

ActionTemplateShowAndApply

protected ActionTemplateShowAndApply(ResponsePage aForward,
                                     ResponsePage aRedirect,
                                     RequestParser aRequestParser)

Constructor.

Parameters:

aForward - used for Operation.Show operations, and also for failed Operation.Apply operations. This is the default response.

aRedirect - used for successful Operation.Apply operations.

aRequestParser - passed to the superclass constructor.

Method Detail

execute

public ResponsePage execute()
                     throws AppException

Template method.

In order to clearly understand the operation of this method, here is the core of its implementation, with all abstract methods in italics :

    if ( Operation.Show == getOperation() ){
      show();
    }
    else if ( Operation.Apply == getOperation() ){
      validateUserInput();
      if( ! hasErrors() ){
        apply();
        if ( ! hasErrors() ){
          setResponsePage(fRedirect);
        }
      }
    }
   

Specified by:

execute in interface Action

Specified by:

execute in class ActionImpl

Throws:

AppException

show

protected abstract void show()
                      throws AppException

Show the input form.

The form may or may not be populated.

Throws:

AppException

validateUserInput

protected abstract void validateUserInput()
                                   throws AppException

Validate items input by the user into a form.

Applied to Operation.Apply. If an error occurs, then addError must be called.

Throws:

AppException

apply

protected abstract void apply()
                       throws AppException

Validate the user input, and then apply an edit to the database. If an error occurs, then addError must be called.

Throws:

AppException