Reflection
PHP Manual

Extending

If you want to create specialized versions of the built-in classes (say, for creating colorized HTML when being exported, having easy-access member variables instead of methods or having utility methods), you may go ahead and extend them.

Exemplo #1 Extending the built-in classes

<?php
/**
 * My Reflection_Method class
 */
class My_Reflection_Method extends ReflectionMethod
{
    public 
$visibility = array();

    public function 
__construct($o$m)
    {
        
parent::__construct($o$m);
        
$this->visibility Reflection::getModifierNames($this->getModifiers());
    }
}

/**
 * Demo class #1
 *
 */
class {
    protected function 
x() {}
}

/**
 * Demo class #2
 *
 */
class extends {
    function 
x() {}
}

// Print out information
var_dump(new My_Reflection_Method('U''x'));
?>

O exemplo acima irá imprimir algo similar à:

object(My_Reflection_Method)#1 (3) {
  ["visibility"]=>
  array(1) {
    [0]=>
    string(6) "public"
  }
  ["name"]=>
  string(1) "x"
  ["class"]=>
  string(1) "U"
}
Cuidado

If you're overwriting the constructor, remember to call the parent's constructor before any code you insert. Failing to do so will result in the following: Fatal error: Internal error: Failed to retrieve the reflection object


Reflection
PHP Manual