Duda con PDO y mi clase

[atrianaster]

@GatorV gracias por tus recomendaciones, aquí les dejo la clase terminada.

Código PHP:

/**
* Registers objects and variables
*
* Makes objects and variables available to any level
* of the application without having to keep track
* of their existence.  Also useful for objects such
* as database connectors that are used globaly and
* not to be duplicated.
*
* PHP version 5
*
* @author Arley Triana Morín <[email protected]>
*/
class Registry
{
    /**
     * Registry of variables and objects
     * @access static private
     * @var array
     */
    static private $registry = array();
 
    /**
     * Adds an item to the registry
     * @access static public 
     * @param string item's unique name
     * @param mixed item
     * @return boolean
     */
    static public function add($name, $item)
    {
        if (!self::exists($name)) {
            self::$registry[$name] = $item;
            return true;
        } else {
            return false;
        }
    }
 
    /**
     * Returns true if item is registered
     * @access static public
     * @param string item's name
     * @return boolean
     */
    static public function exists($name)
    {
        if (is_string($name)) {
            return array_key_exists($name, self::$registry);
        } else {
            throw new Exception('Registry item\'s name must be a string');
        }
    }
 
    /**
     * Returns registered item
     * @access static public
     * @param string item's name
     * @return mixed (null if name is not in registry)
     */
    static public function get($name)
    {
        if (self::exists($name)) {
            $return = self::$registry[$name];
        } else {
            $return = null;
        }
        return $return;
    }
 
    /**
     * Removes a registry entry
     * @access static public
     * @param string item's name
     * @return boolean
     */
    static public function remove($name)
    {
        if (self::exists($name)) {
            unset(self::$registry[$name]);
        }
        return true;
    }
 
    /**
     * Clears the entire registry
     * @access static public
     * @return boolean
     */
    static public function clear()
    {
        self::$registry = array();
    }
}
?>
 

Como Usar?

Código PHP:

<?php
require_once 'registry.php';
 
//sets and registers a variable
$item = 'Here is a registered variable';
registry::add('Variable', $item);
 
/**
* Test class that echos a registered variable
*/
class Test
{
    private $item;
 
    public function __construct() {
        $this->item = Registry::get('Variable');
    }
 
    public function get() {
        echo '<p>'.$this->item.'</p>';
    }
}
 
//will return "Here is a registered variable"
$test = new Test();
$test->get();
 
//tests if "Variable" exists
if (Registry::exists('Variable')) {
    echo '<p>"Variable" exists</p>';
} else {
    echo '<p>"Variable" does not exists</p>';
}
 
//tests if "variable" exists
if (Registry::exists('variable')) {
    echo '<p>"variable" exists</p>';
} else {
    echo '<p>"variable" does not exists</p>';
}
 
//removes "Variable"
Registry::remove('Variable');
?>