Symfony\Component\Form\PropertyPath::updateProperty PHP Method

    protected function updateProperty(&$objectOrArray, $currentIndex, $value)
    {
        $property = $this->elements[$currentIndex];

        if (is_object($objectOrArray) && $this->isIndex[$currentIndex]) {
            if (!$objectOrArray instanceof \ArrayAccess) {
                throw new InvalidPropertyException(sprintf('Index "%s" cannot be modified in object of type "%s" because it doesn\'t implement \ArrayAccess', $property, get_class($objectOrArray)));
            }

            $objectOrArray[$property] = $value;
        } else if (is_object($objectOrArray)) {
            $reflClass = new \ReflectionClass($objectOrArray);
            $setter = 'set'.$this->camelize($property);

            if ($reflClass->hasMethod($setter)) {
                if (!$reflClass->getMethod($setter)->isPublic()) {
                    throw new PropertyAccessDeniedException(sprintf('Method "%s()" is not public in class "%s"', $setter, $reflClass->getName()));
                }

                $objectOrArray->$setter($value);
            } else if ($reflClass->hasProperty($property)) {
                if (!$reflClass->getProperty($property)->isPublic()) {
                    throw new PropertyAccessDeniedException(sprintf('Property "%s" is not public in class "%s". Maybe you should create the method "set%s()"?', $property, $reflClass->getName(), ucfirst($property)));
                }

                $objectOrArray->$property = $value;
            } else if (property_exists($objectOrArray, $property) || $reflClass->hasMethod('__get')) {
                // needed to support \stdClass instances
                $objectOrArray->$property = $value;
            } else {
                throw new InvalidPropertyException(sprintf('Neither element "%s" nor method "%s()" exists in class "%s"', $property, $setter, $reflClass->getName()));
            }
        } else {
            $objectOrArray[$property] = $value;
        }
    }