singleton comeback

satella/coding/__init__.py

@@ -13,7 +13,7 @@ from .typecheck import typed, Callable, Sequence, \
     Number, coerce, Set, Dict, List, Tuple, checked_coerce, for_argument, \
     precondition, PreconditionError
 from .structures import TimeBasedHeap, Heap, typednamedtuple, OmniHashableMixin
-from singleton_decorator import singleton as Singleton
+from .singleton import Singleton
 
 
 __all__ = [

satella/coding/singleton.py

+"""
+Taken from module pypi/singleton-decorator
+"""
+
+class _SingletonWrapper:
+    """
+    A singleton wrapper class. Its instances would be created
+    for each decorated class.
+    """
+
+    def __init__(self, cls):
+        self.__wrapped__ = cls
+        self._instance = None
+
+    def __call__(self, *args, **kwargs):
+        """Returns a single instance of decorated class"""
+        if self._instance is None:
+            self._instance = self.__wrapped__(*args, **kwargs)
+        return self._instance
+
+
+def Singleton(cls):
+    """
+    A singleton decorator. Returns a wrapper objects. A call on that object
+    returns a single instance object of decorated class. Use the __wrapped__
+    attribute to access decorated class directly in unit tests
+    """
+    return _SingletonWrapper(cls)

setup.py

@@ -9,7 +9,6 @@ setup(keywords=['ha', 'high availability', 'scalable', 'scalability', 'server'],
           "six",
           "monotonic",
           "typing",
-          'singleton-decorator==1.0.0'
       ],
       tests_require=[
           "nose", "mock", "coverage"