cqltypes.py 文件源码

def apply_parameters(cls, subtypes, names=None):
        """
        Given a set of other CassandraTypes, create a new subtype of this type
        using them as parameters. This is how composite types are constructed.

            >>> MapType.apply_parameters([DateType, BooleanType])
            <class 'cassandra.cqltypes.MapType(DateType, BooleanType)'>

        `subtypes` will be a sequence of CassandraTypes.  If provided, `names`
        will be an equally long sequence of column names or Nones.
        """
        if cls.num_subtypes != 'UNKNOWN' and len(subtypes) != cls.num_subtypes:
            raise ValueError("%s types require %d subtypes (%d given)"
                             % (cls.typename, cls.num_subtypes, len(subtypes)))
        newname = cls.cass_parameterized_type_with(subtypes)
        if six.PY2 and isinstance(newname, unicode):
            newname = newname.encode('utf-8')
        return type(newname, (cls,), {'subtypes': subtypes, 'cassname': cls.cassname, 'fieldnames': names})