public function getLogger($class_name = UNDEFINED)
    {
        if (is_null($this->logger)) {
            $this->logger = $this->add($class_name === UNDEFINED
                                            ? $this->logger_class
                                            : $class_name);
        }

        return $this->logger;
    }
public function getLogger($class_name = UNDEFINED)
    {
        if (is_null($this->logger)) {
            $this->logger = $this->add($class_name === UNDEFINED
                                            ? $this->logger_class
                                            : $class_name);
        }

        return $this->logger;
    }
public function getLogger ( $ class_name = UNDEFINED ) { if ( is_null ( $ this -> logger ) ) { $ this -> logger = $ this -> add ( $ class_name === UNDEFINED ? $ this -> logger_class : $ class_name ) ; } return $ this -> logger ; }
Initialize logger or return existing one.

@param string $class_name

@return Logger
Initialize logger or return existing one .