def __init__(self, name, coder=None, combine_fn=None): # type: (str, Optional[Coder], Any) -> None """Initialize the specification for CombiningValue state. CombiningValueStateSpec(name, combine_fn) -> Coder-inferred combining value state spec. CombiningValueStateSpec(name, coder, combine_fn) -> Combining value state spec with coder and combine_fn specified. Args: name (str): The name by which the state is identified. coder (Coder): Coder specifying how to encode the values to be combined. May be inferred. combine_fn (``CombineFn`` or ``callable``): Function specifying how to combine the values passed to state. """ # Avoid circular import. from apache_beam.transforms.core import CombineFn # We want the coder to be optional, but unfortunately it comes # before the non-optional combine_fn parameter, which we can't # change for backwards compatibility reasons. # # Instead, allow it to be omitted (by either passing two arguments # or combine_fn by keyword.) if combine_fn is None: if coder is None: raise ValueError('combine_fn must be provided') else: coder, combine_fn = None, coder self.combine_fn = CombineFn.maybe_from_callable(combine_fn) # The coder here should be for the accumulator type of the given CombineFn. if coder is None: coder = self.combine_fn.get_accumulator_coder() super(CombiningValueStateSpec, self).__init__(name, coder)
def __init__(self, name, coder, combine_fn): # Avoid circular import. from apache_beam.transforms.core import CombineFn assert isinstance(name, str) assert isinstance(coder, Coder) self.name = name # The coder here should be for the accumulator type of the given CombineFn. self.coder = coder self.combine_fn = CombineFn.maybe_from_callable(combine_fn)
def __init__(self, name, coder, combine_fn): # Avoid circular import. from apache_beam.transforms.core import CombineFn assert isinstance(name, str) assert isinstance(coder, Coder) self.name = name # The coder here should be for the accumulator type of the given CombineFn. self.coder = coder self.combine_fn = CombineFn.maybe_from_callable(combine_fn)