framework/log/Dispatcher.php
public function getLogger()
    {
        if ($this->_logger === null) {
            $this->setLogger(Yii::getLogger());
        }

        return $this->_logger;
    }
public function getLogger()
    {
        if ($this->_logger === null) {
            $this->setLogger(Yii::getLogger());
        }

        return $this->_logger;
    }
Gets the connected logger.
If not set, [[\Yii::getLogger()]] will be used.
@property Logger the logger. If not set, [[\Yii::getLogger()]] will be used.
@return Logger the logger.