Run the mapper on the hadoop node.

def run_mapper(self, stdin=sys.stdin, stdout=sys.stdout):
        """
        Run the mapper on the hadoop node.
        """
        self.init_hadoop()
        self.init_mapper()
        outputs = self._map_input((line[:-1] for line in stdin))
        if self.reducer == NotImplemented:
            self.writer(outputs, stdout)
        else:
            self.internal_writer(outputs, stdout)