Doctrine_manual-1-2-en

Chapter 2: Getting Started 22
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// bootstrap.php
/**
* Bootstrap Doctrine.php, register autoloader specify
* configuration attributes and load models.
*/
require_once(dirname(__FILE__) . '/lib/vendor/doctrine/Doctrine.php');
Register Autoloader
Now that we have the Doctrine class present, we need to register the class autoloader
function in the bootstrap file:
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// bootstrap.php
// ...
spl_autoload_register(array('Doctrine', 'autoload'));
Lets also create the singleton Doctrine_Manager instance and assign it to a variable named
$manager:
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// bootstrap.php
// ...
$manager = Doctrine_Manager::getInstance();
Autoloading Explained
You can read about the PHP autoloading on the php website 17 . Using the autoloader allows
us to lazily load classes as they are requested instead of pre-loading all classes. This is a
huge benefit to performance.
The way the Doctrine autoloader works is simple. Because our class names and paths are
related, we can determine the path to a Doctrine class based on its name.
Imagine we have a class named Doctrine_Some_Class and we instantiate an instance of it:
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$class = new Doctrine_Some_Class();
The above code will trigger a call to the Doctrine_Core::autoload() function and pass it
the name of the class instantiated. The class name string is manipulated and transformed in
to a path and required. Below is some pseudo code that shows how the class is found and
required:
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class Doctrine
{
public function autoload($className)
{
$classPath = str_replace('_', '/', $className) . '.php';
$path = '/path/to/doctrine/' . $classPath;
require_once($path);
return true;
}
}
17. http://www.php.net/spl_autoload_register
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