class = $class; $this->relation = $relation; } /** * Determine if the validation rule passes. * * @param string $attribute * @param mixed $value * @return bool */ public function passes($attribute, $value) { $relation = $this->relation; if ($this->class::find($value)->$relation()->exists()) { return false; } return true; } /** * Get the validation error message. * * @return string */ public function message() { return "Relation {$this->relation} exists."; } }