Base implementation for ClassRegistry

objtools/registry.py

@@ -0,0 +1,47 @@
+from typing import MutableMapping, Any, Callable
+from cached_property import cached_property
+
+
+class ClassRegistry(MutableMapping[str, Callable]):
+
+    def check_key(self, key: str) -> None:
+        pass
+
+    def check_value(self, value: Callable) -> None:
+        pass
+
+    def check(self, key: str, value: Callable) -> None:
+        try:
+            self.check_key(key)
+        except KeyError:
+            raise
+        except Exception as e:
+            raise KeyError(str(e))
+
+        try:
+            self.check_value(value)
+        except ValueError:
+            raise
+        except Exception as e:
+            raise ValueError(str(e))
+
+    def register(self, key: str, value: Callable) -> None:
+        self[key] = value
+
+    def unregister(self, key: str) -> None:
+        del self[key]
+
+    def __setitem__(self, key: str, value: Callable) -> None:
+        self.check(key, value)
+        super().__setitem__(key, value)
+
+    @cached_property
+    def metaclass(self) -> type:
+        class RegistryMetaclass(type):
+
+            def __new__(cls, name: str, *args: Any, **kwargs: Any) -> type:
+                newclass = super().__new__(cls, name, *args, **kwargs)
+                self.register(name, newclass)
+                return newclass
+
+        return RegistryMetaclass

requirements.txt

@@ -0,0 +1 @@
+cached-property>=1.5.1