The Mojavi 3 Book/Tutorials/Global Templating - The Decorator Pattern

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Ever since Mojavi 3 was released earlier this year, people have been looking to create a flexible global templating solution. From using post filters to page controllers, people have been looking for a way to create simple and manageable global templates that will allow for a great deal of flexibility without compromising the need for larges amount of duplicated code.

++ Enter Decorator

The Decorator design pattern, like every other pattern, is nothing more than a way to talk about a resuable concept, or pattern, that a programmer might encounter while coding applications. The Decorator pattern's strength is it's ability to serve as a wrapper for that particular object, while leaving objects like it in tact.

The Decorator pattern has been implemented in the =View= class, providing a number of new methods:

public function setSlot ($attributeName, $moduleName, $actionName) public function setDecoratorDirectory ($directory) public function isDecorator () protected function & getSlots () public function getDecoratorTemplate () public function getDecoratorDirectory () protected function & decorate (&$content)

Now a brief explanation of what each of these do:

  • =setSlot= - Creates a slot entry based upon the results of a specially controlled controller->forward()
  • =setDecoratorTemplate= - Sets the template that you're going to use for your decorator. This method also automatically turns the decorator switch to =true=
  • =isDecorator= - returns true is setDecoratorTemplate has been called, otherwise false.
  • =getSlots= - Returns an array of the slots.
  • =getDecoratorTemplate= - Returns the decorator template.
  • =getDecoratorDirectory= - Returns the decorator directory.
  • =decorate= - A method that must be implemented in derivate Views.

Note: these functions are in View, so all derivates of View (i.e. PHPView) have access.

++ Insert Here: Slots

Slots is a new name for an old concept. More or less, slots serve as placeholders that can be populated by the results of a =$controller->forward($mod, $act)= call. And, as you can see, the =setSlot= method takes three parameters:

public function setSlot ($attributeName, $moduleName, $actionName)

The first parameter, $attributeName, serves as the name of the slot. The next two parameters will be used to get the results of that Action, put it in a buffer, and place it into the internal =$slots= member variable.

++ Let's Decorate!

The usage pattern of Views changes little with the implementation of the decorator pattern at the module level (though secondary View authors, i.e. SmartyView et al., do have a few things to play with).

Now let's look at what you're going to need to do implement the new, and NEW decorator features of Mojavi.

+++ Creating a Global Template

First off, we're going to need a great big christma..ehh..template to decorate. While I won't get into breaking down and factoring our global template, keep in mind that this is not the only way to do this.

Example 2: The Christmas Tree (myGlobalTemplate.php)[edit]

Side note: Sometimes you'll have issues with that <?xml [....] ?> declaration, an easy workaround is to disable short tags in your php.ini file, or to use ini_set() to disable it. <?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-us">

<head>

<title><?php echo $template['title']; ?></title>

<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=utf-8"/> <style type="text/css" media="all">

<?php echo $template['css']; ?>

</style>

</head>

<body>

<?php echo $template['content']; ?>

</body> </html>

+++ Putting the ornaments up So now that we have our decorator template, we need to decorate it. The decorating process is fairly simple, and consists of the following simple steps:

  • Setting the decorator directory using =setDecoratorDirectory()= (Optional)
  • Setting the decorator template using =setDecoratorTemplate()=
  • Setting slots =setSlot()=

For example,

Example 3: In the View (IndexSuccessView.class.php)[edit]

class IndexSuccessView extends PHPView {

public function execute () {

// set our template $this->setTemplate('IndexSuccess.php');

//setup our decorator template $this->setDecoratorDirectory(MO_TEMPLATE_DIR); $this->setDecoratorTemplate('myGlobalTemplate.php');

//setup our slots //(SlotName, Module, Action) $this->setSlot('menu', 'Content', 'PopulateMenu'); $this->setSlot('css', 'Content', 'PopulateCss'); // set the title $this->setAttribute('title', 'Default Action');

}

}

Now you might be wondering where the =content= slot is being populated. Well, =content= is a reserved slot that is automatically populated with the output of the originally requested Action/View pair. /To be Continued..../