public function addPropertyConstraint($property, Constraint $constraint)
    {
        if (!isset($this->properties[$property])) {
            $this->properties[$property] = new PropertyMetadata($this->getClassName(), $property);

            $this->addPropertyMetadata($this->properties[$property]);
        }

        $constraint->addImplicitGroupName($this->getDefaultGroup());

        $this->properties[$property]->addConstraint($constraint);

        return $this;
    }