Structural Design Pattern: Bridge Pattern

app/data/__init__.py

@@ -1,21 +1,38 @@
 """app.data"""
-from ..services.location.csbs import CSBSLocationService
-from ..services.location.jhu import JhuLocationService
-from ..services.location.nyt import NYTLocationService
+from ..services.location.csbs import CSBSLocationServicee
+from ..services.location.jhu import JhuLocationServicee
+from ..services.location.nyt import NYTLocationServicee
+from app.services.location.__init__ import LocationServicer
 
-# Mapping of services to data-sources.
-DATA_SOURCES = {
-    "jhu": JhuLocationService(),
-    "csbs": CSBSLocationService(),
-    "nyt": NYTLocationService(),
-}
+class DataSourceSingletonMeta(type):
+    """
+    access point to the DataSource 
+    """
 
+    _instances = {}
 
-def data_source(source):
-    """
-    Retrieves the provided data-source service.
+    def __call__(cls, *args, **kwargs):
+        """
+        Possible changes to the value of the `__init__` argument do not affect
+        the returned instance.
+        """
+        if cls not in cls._instances:
+            instance = super().__call__(*args, **kwargs)
+            cls._instances[cls] = instance
+        return cls._instances[cls]
 
-    :returns: The service.
-    :rtype: LocationService
-    """
-    return DATA_SOURCES.get(source.lower())
+
+class DataSourceSingleton(metaclass=DataSourceSingletonMeta):
+        DATA_SOURCES = {
+            "jhu": LocationServicer(JhuLocationServicee()),
+            "csbs": LocationServicer(CSBSLocationServicee()),
+            "nyt": LocationServicer(NYTLocationServicee()),
+        }
+        def get_data_source(self, dataSource):
+            return self.DATA_SOURCES.get(dataSource.lower())
+        ...
+
+        def get_data_source_list(self): 
+            return self.DATA_SOURCES
+
+

app/services/location/__init__.py

@@ -2,27 +2,34 @@
 from abc import ABC, abstractmethod
 
 
-class LocationService(ABC):
+class LocationServicer: # The 'Remote' of the Pattern
     """
-    Service for retrieving locations.
+    Abstraction class handling the 'Front End' portion of the project
     """
-
     @abstractmethod
-    async def get_all(self):
-        """
-        Gets and returns all of the locations.
+    def __init__(self, implementation):
+        self.implementation = implementation
+
+    @abstractmethod
+    def all_locations(self):
+        return self.implementation.get_all()
+
+    @abstractmethod
+    def locations(self):
+        return self.implementation.get()
+
+class LocationServicee: # The 'Device' with the implmentation
+    """
+    Implementation Interface
+    """
+
+    def get_all(self):
+        # No implementation - interface method
+        pass
+
+    def get(self):
+        # No implementation - interface method
+        pass
+
 
-        :returns: The locations.
-        :rtype: List[Location]
-        """
-        raise NotImplementedError
 
-    @abstractmethod
-    async def get(self, id):  # pylint: disable=redefined-builtin,invalid-name
-        """
-        Gets and returns location with the provided id.
-
-        :returns: The location.
-        :rtype: Location
-        """
-        raise NotImplementedError