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from abc import abstractmethod
from typing import Dict, Optional

from gravitino.api.auditable import Auditable
from gravitino.api.tag.supports_tags import SupportsTags
from gravitino.exceptions.base import UnsupportedOperationException


class Schema(Auditable):
    """
    An interface representing a schema in the Catalog. A Schema is a
    basic container of relational objects, like tables, views, etc. A Schema can be self-nested,
    which means it can be schema1.schema2.table.

    This defines the basic properties of a schema. A catalog implementation with SupportsSchemas
    should implement this interface.
    """

    @abstractmethod
    def name(self) -> str:
        """Returns the name of the Schema."""
        pass

    def comment(self) -> Optional[str]:
        """Returns the comment of the Schema. None is returned if the comment is not set."""
        return None

    def properties(self) -> Dict[str, str]:
        """Returns the properties of the Schema. An empty dictionary is returned if no properties are set."""
        return {}

    def supports_tags(self) -> SupportsTags:
        raise UnsupportedOperationException("Schema does not support tag operations.")
