Sets the ruler type for this ruler to the inputed type.
        
        :param      rulerType | <XChartRuler.Type>

def setRulerType( self, rulerType ):
        """
        Sets the ruler type for this ruler to the inputed type.
        
        :param      rulerType | <XChartRuler.Type>
        """
        self._rulerType = rulerType
        self.clear()
        
        # handle custom types
        if ( rulerType == XChartRuler.Type.Monthly ):
            self.setNotches(['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
                             'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'])