Global Templating - The Decorator Pattern
* Enter Decorator
* Insert Here: Slots
* Let’s Decorate!
o Creating a Global Template
o Putting the ornaments up
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 managable 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 (ie 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 $controller->foward($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 memeber 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, ie 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)
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”>
<!–Css slot–>
<?php echo $template['css']; ?>
</style>
</head>
<body>
<!–menu slot–>
<div id=”menu”>
<?php echo $template['menu']; ?>
</div>
<!–main content slot–>
<div id=”main”>
<?php echo $template['content']; ?>
</div>
</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)
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….
