A simple php custom exception class

/**
* Customize an exception handling class
*/
class MyException extends Exception
{
 // Redefine the constructor to make message a property that must be specified
 public function __construct ($message, $code = 0) {
 // Customized code
 // Make sure all variables are assigned correctly
 parent::__construct($message, $code);
 }
 // Customized string output Style
 public function __toString() {
 return __CLASS__ . ": [{$this->code}]: {$this->message}n";
 }
}

* Create a class for testing exception handling mechanism
*/
class TestException
{
 function __construct($str) {
 if($str == 1)
 throw new MyException('The parameter cannot be 1',1);
 elseif( $str == 2)
 throw new MyException('The parameter cannot be 2',2);//Throw 2 exceptions
 else
 echo $str;
 }
}
 try {
 $o = new TestException(2);
} catch (MyException $e) { // Catch exception
 echo $e;
}
?>