1# Copyright 2015 gRPC authors.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14"""Interfaces related to streams of values or objects."""
15
16import abc
17
18import six
19
20
21class Consumer(six.with_metaclass(abc.ABCMeta)):
22    """Interface for consumers of finite streams of values or objects."""
23
24    @abc.abstractmethod
25    def consume(self, value):
26        """Accepts a value.
27
28    Args:
29      value: Any value accepted by this Consumer.
30    """
31        raise NotImplementedError()
32
33    @abc.abstractmethod
34    def terminate(self):
35        """Indicates to this Consumer that no more values will be supplied."""
36        raise NotImplementedError()
37
38    @abc.abstractmethod
39    def consume_and_terminate(self, value):
40        """Supplies a value and signals that no more values will be supplied.
41
42    Args:
43      value: Any value accepted by this Consumer.
44    """
45        raise NotImplementedError()
46