General setter with possibility of set default value suitable for writing other setters

general-setter.php

class Product
{

    /**
     * Product name to be set
     *
     * @var string
     */
    private $_name;

    /**
     * General setter prototype
     *
     * @param $variable
     * @param $value
     * @param $defaultValue
     * @return bool If true - value has been set, if false - default value used
     */
    private function _generalSetter($variable, $value, $defaultValue){

        if(empty($value) === false){
            $variable = $value;
            return true;
        }
        else{
            $variable = $defaultValue;
            return false;
        }
    }

    /**
     * Setter for product name
     *
     * This setter uses general setter above to be more simple
     *
     * @param $productName
     * @return bool
     */
    public function setProductName($productName){
        return $this->_generalSetter($this->_name, $productName, 'Box of milk');
    }

}