wrapper pattern for repository

hjwp · hjwp · commit 272b65cde166 · 2020-01-10T22:41:42.000Z
diff --git a/src/allocation/adapters/repository.py b/src/allocation/adapters/repository.py
@@ -1,41 +1,44 @@
-import abc
-from typing import Set
+from typing import Set, Protocol
 from allocation.domain import model
 
 
-class AbstractRepository(abc.ABC):
 
-    def __init__(self):
+class AbstractRepository(Protocol):
+
+    def add(self, product: model.Product):
+        ...
+
+    def get(self, sku) -> model.Product:
+        ...
+
+
+
+class TrackingRepository:
+    seen: Set[model.Product]
+
+    def __init__(self, repo: AbstractRepository):
         self.seen = set()  # type: Set[model.Product]
+        self._repo = repo
 
     def add(self, product: model.Product):
-        self._add(product)
+        self._repo.add(product)
         self.seen.add(product)
 
     def get(self, sku) -> model.Product:
-        product = self._get(sku)
+        product = self._repo.get(sku)
         if product:
             self.seen.add(product)
         return product
 
-    @abc.abstractmethod
-    def _add(self, product: model.Product):
-        raise NotImplementedError
-
-    @abc.abstractmethod
-    def _get(self, sku) -> model.Product:
-        raise NotImplementedError
-
 
 
-class SqlAlchemyRepository(AbstractRepository):
+class SqlAlchemyRepository:
 
     def __init__(self, session):
-        super().__init__()
         self.session = session
 
-    def _add(self, product):
+    def add(self, product):
         self.session.add(product)
 
-    def _get(self, sku):
+    def get(self, sku):
         return self.session.query(model.Product).filter_by(sku=sku).first()
diff --git a/src/allocation/service_layer/unit_of_work.py b/src/allocation/service_layer/unit_of_work.py
@@ -53,7 +53,9 @@ def __init__(self, session_factory=DEFAULT_SESSION_FACTORY):
 
     def __enter__(self):
         self.session = self.session_factory()  # type: Session
-        self.products = repository.SqlAlchemyRepository(self.session)
+        self.products = repository.TrackingRepository(
+            repository.SqlAlchemyRepository(self.session)
+        )
         return super().__enter__()
 
     def __exit__(self, *args):
