TalkPHP - View Single Post - Tripwire Class (Much like the Java "final" keyword for PHP)

Wildhoney · 01-27-2008, 05:29 PM

Well, I created this little class - not for any particular purpose, because let's be honest, it's pretty useless, but it is quite nifty! Basically, all you have to do is arm (or set) a variable, and then let the class do the rest. If the variable value changes from what it was when you set it, an exception will be thrown.

We use it like so:

php Code:

class Tripwire
{
    private static $m_aVars;
    private static $m_bStarted;
    const MESSAGE = 'Variable "%s" has been modified from "%s" to "%s".';
    
    public static function init()
    {
        declare(ticks = 1);
        self::$m_bStarted = true;
        register_tick_function
        (
            create_function
            (
                null,
                'Tripwire::check();'
            )
        );
    }
    
    public static function set($szVar)
    {
        global ${$szVar};
        
        if(self::$m_bStarted == false)
        {
            self::init();
        }
        
        self::$m_aVars[] = array
        (
            'var' => $szVar,
            'data' => ${$szVar}
        );
    }
    
    public static function check()
    {
        if(!isset(self::$m_aVars))
        {
            return;
        }
        
        foreach(self::$m_aVars as $aVar)
        {
            global ${$aVar['var']};
            
            if(${$aVar['var']} != $aVar['data'])
            {
                throw new Exception(sprintf(self::MESSAGE, $aVar['var'], $aVar['data'], ${$aVar['var']}));
            }
        }
    }
}

try
{
    $szText = 'Adam';
    Tripwire::set('szText');
    $szText = 'Karl';
}
catch(Exception $pEx)
{
    die($pEx->getMessage());
}