respect-validation/library/Rules/Attribute.php

<?php

/*
 * This file is part of Respect/Validation.
 *
 * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
 *
 * For the full copyright and license information, please view the "LICENSE.md"
 * file that was distributed with this source code.
 */

namespace Respect\Validation\Rules;

use ReflectionProperty;
use Respect\Validation\Exceptions\ComponentException;
use Respect\Validation\Validatable;

class Attribute extends AbstractRelated
{
    public function __construct($reference, Validatable $validator = null, $mandatory = true)
    {
        if (!is_string($reference) || empty($reference)) {
            throw new ComponentException('Invalid attribute/property name');
        }

        parent::__construct($reference, $validator, $mandatory);
    }

    public function getReferenceValue($input)
    {
        $propertyMirror = new ReflectionProperty($input, $this->reference);
        $propertyMirror->setAccessible(true);

        return $propertyMirror->getValue($input);
    }

    public function hasReference($input)
    {
        return is_object($input) && property_exists($input, $this->reference);
    }
}