Refactor serializers and update Queue constructors with type hints

ipcqueue/posixmq.py

@@ -2,7 +2,9 @@
 Interprocess POSIX message queue implementation.
 """
 
-from .serializers import PickleSerializer
+from typing import Type
+
+from .serializers import PickleSerializer, SerializerBase
 
 try:
     import Queue as queue
@@ -73,7 +75,7 @@ class Queue(object):
     POSIX message queue.
     """
 
-    def __init__(self, name, maxsize=10, maxmsgsize=1024, serializer=PickleSerializer):
+    def __init__(self, name, maxsize=10, maxmsgsize=1024, serializer: Type[SerializerBase]=PickleSerializer):
         """
         Constructor for message queue. *name* is an unique identifier of the
         queue, must starts with ``/``. *maxsize* is an integer that sets

ipcqueue/serializers.py

@@ -1,9 +1,24 @@
+import abc
+from typing import Any
+
 try:
     import cPickle as pickle
 except ImportError:
     import pickle
 
 
+class SerializerBase(abc.ABC):
+    @staticmethod
+    @abc.abstractmethod
+    def dumps(obj) -> bytes:
+        raise NotImplementedError()
+
+    @staticmethod
+    @abc.abstractmethod
+    def loads(obj) -> Any:
+        raise NotImplementedError()
+
+
 class PickleSerializer:
     @staticmethod
     def dumps(obj):

ipcqueue/sysvmq.py

@@ -2,7 +2,9 @@
 Interprocess SYS V message queue implementation.
 """
 
-from .serializers import PickleSerializer
+from typing import Type
+
+from .serializers import PickleSerializer, SerializerBase
 
 try:
     import Queue as queue
@@ -58,7 +60,7 @@ class Queue(object):
     SYS V message queue.
     """
 
-    def __init__(self, key=None, max_bytes=None, serializer=PickleSerializer):
+    def __init__(self, key=None, max_bytes=None, serializer: Type[SerializerBase]=PickleSerializer):
         """
         Constructor for message queue. *key* is an unique identifier of
         the queue, must be positive number or ``0`` for private queue.