PROTON-2892: [Python] Use python library IntFlag for Endpoint state

Author: astitcher

python/proton/_endpoints.py

@@ -65,6 +65,7 @@
 from ._wrapper import Wrapper
 
 from collections.abc import Iterator
+from enum import IntFlag
 from typing import Any, Callable, ClassVar, Optional, Union, TYPE_CHECKING, overload
 
 if TYPE_CHECKING:
@@ -74,25 +75,11 @@
     from ._message import Message
 
 
-class Endpoint(Wrapper):
+class EndpointState(IntFlag):
     """
-    Abstract class from which :class:`Connection`, :class:`Session`
-    and :class:`Link` are derived, and which defines the state
-    of these classes.
-
-    The :class:`Endpoint` state is an integral value with flags that
+    The state of an AMQP endpoint. This is a bit field with flags that
     encode both the local and remote state of an AMQP Endpoint
     (:class:`Connection`, :class:`Link`, or :class:`Session`).
-    The individual bits may be accessed using :const:`LOCAL_UNINIT`,
-    :const:`LOCAL_ACTIVE`, :const:`LOCAL_CLOSED`, and
-    :const:`REMOTE_UNINIT`, :const:`REMOTE_ACTIVE`, :const:`REMOTE_CLOSED`.
-
-    Every AMQP endpoint (:class:`Connection`, :class:`Link`, or
-    :class:`Session`) starts out in an uninitialized state and then
-    proceeds linearly to an active and then closed state. This
-    lifecycle occurs at both endpoints involved, and so the state
-    model for an endpoint includes not only the known local state,
-    but also the last known state of the remote endpoint.
     """
 
     LOCAL_UNINIT = PN_LOCAL_UNINIT
@@ -113,9 +100,38 @@ class Endpoint(Wrapper):
     REMOTE_CLOSED = PN_REMOTE_CLOSED
     """ The remote endpoint state is closed. """
 
+
+class Endpoint(Wrapper):
+    """
+    Abstract class from which :class:`Connection`, :class:`Session`
+    and :class:`Link` are derived, and which defines the state
+    of these classes.
+
+    The :class:`Endpoint` state is an integral value with flags that
+    encode both the local and remote state of an AMQP Endpoint
+    (:class:`Connection`, :class:`Link`, or :class:`Session`).
+    The individual bits may be accessed using :const:`LOCAL_UNINIT`,
+    :const:`LOCAL_ACTIVE`, :const:`LOCAL_CLOSED`, and
+    :const:`REMOTE_UNINIT`, :const:`REMOTE_ACTIVE`, :const:`REMOTE_CLOSED`.
+
+    Every AMQP endpoint (:class:`Connection`, :class:`Link`, or
+    :class:`Session`) starts out in an uninitialized state and then
+    proceeds linearly to an active and then closed state. This
+    lifecycle occurs at both endpoints involved, and so the state
+    model for an endpoint includes not only the known local state,
+    but also the last known state of the remote endpoint.
+    """
+
+    LOCAL_UNINIT = EndpointState.LOCAL_UNINIT
+    REMOTE_UNINIT = EndpointState.REMOTE_UNINIT
+    LOCAL_ACTIVE = EndpointState.LOCAL_ACTIVE
+    REMOTE_ACTIVE = EndpointState.REMOTE_ACTIVE
+    LOCAL_CLOSED = EndpointState.LOCAL_CLOSED
+    REMOTE_CLOSED = EndpointState.REMOTE_CLOSED
+
     get_condition: ClassVar[Callable[[Any], Any]]
     get_remote_condition: ClassVar[Callable[[Any], Any]]
-    get_state: ClassVar[Callable[[Any], int]]
+    get_state: ClassVar[Callable[[Any], EndpointState]]
 
     def __init__(self) -> None:
         self.condition: Optional['Condition'] = None
@@ -133,7 +149,7 @@ def remote_condition(self) -> Optional['Condition']:
         return cond2obj(type(self).get_remote_condition(self._impl))
 
     @property
-    def state(self) -> int:
+    def state(self) -> EndpointState:
         """
         The state of the endpoint as a bit field. The state has a local
         and a remote component. Each of these can be in one of three