Validation rules for Kohana 3.2 (kinda)

RegistrationForm.php

<?php
class RegistrationForm extends Validation {
	public function __construct(Array $array) {
		parent::__construct($array);
		$this->rule('username', 'not_empty');
		$this->rule('password', 'not_empty');
		$this->rule('password_confirmation', 'matches', array(':validation', 'confirm', 'password'));
	}
	
	public function check() {
		$this['username'] = trim($this['username']);
		return parent::__check();
	}
	
	public function offsetSet($offset, $value) {
		$this->_data[$offset] = $value;
	}
}