make Entity an annotation (python decorator) and start building a model in C

Author: Ivan Dlugos

objectbox/builder.py

@@ -8,4 +8,7 @@ def __init__(self):
 
     def model(self, model: Model) -> 'Builder':
         self.__model = model
-        pass
+        return self
+
+    def build(self) -> 'ObjectBox':
+        return self

objectbox/model/__init__.py

@@ -5,6 +5,5 @@
 __all__ = [
     'Model',
     'Entity',
-
     'Id'
 ]

objectbox/model/entity.py

@@ -1,2 +1,28 @@
-class Entity:
-    pass
+# entity decorator
+class _Entity(object):
+    def __init__(self, cls, id: int, uid: int):
+        self.cls = cls
+        self.name: str = cls.__name__
+        self.id = id
+        self.uid = uid
+
+        # currently, ID and UID are mandatory and are not fetched from the model.json
+        if id <= 0:
+            raise ValueError("invalid or no 'id; given in the @Entity annotation")
+
+        if uid <= 0:
+            raise ValueError("invalid or no 'uid' given in the @Entity annotation")
+
+    def __call__(self):
+        return self.cls()
+
+
+# wrap _Entity to allow @Entity(id=, uid=), i.e. no class argument
+def Entity(cls=None, id: int = 0, uid: int = 0):
+    if cls:
+        return _Entity(cls, id, uid)
+    else:
+        def wrapper(cls):
+            return _Entity(cls, id, uid)
+
+        return wrapper

objectbox/model/model.py

@@ -1,4 +1,6 @@
-from objectbox.model import Entity
+from objectbox.model.entity import _Entity
+from objectbox.c import *
+
 from typing import List
 
 
@@ -20,13 +22,15 @@ class Model:
     retired_index_uids: List[int]
     retired_relation_uids: List[int]
 
-    __entities: List[type]
-
     def __init__(self):
-        self.__entities = list()
+        self.__entities: List[type] = list()
+        self.__model = obx_model_create()
+
+    def entity(self, entity: _Entity):
+        if not isinstance(entity, _Entity):
+            raise ValueError("Given type is not an Entity. Are you passing an instance instead of a type or did you "
+                             "forget the '@Entity' annotation?")
 
-    def add_entity(self, entity_type: type):
-        if not issubclass(entity_type, Entity):
-            raise ValueError("given type is not a subclass of 'Entity'")
+        obx_model_entity(self.__model, entity.name.encode('utf-8'), entity.id, entity.uid)
 
-        self.__entities.append(entity_type)
+        self.__entities.append(entity)

objectbox/model/properties.py

@@ -1,9 +1,10 @@
 class Property:
-    __slots__ = ['is_id', 'py_type']
+    __is_id: bool
+    __py_type: type
 
     def __init__(self, py_type: type):
-        self.is_id = isinstance(self, Id)
-        self.py_type = py_type
+        self.__is_id = isinstance(self, Id)
+        self.__py_type = py_type
 
 
 class Id(Property):

tests/model.py

@@ -1,5 +1,6 @@
 from objectbox.model import *
 
 
-class TestEntity(Entity):
+@Entity(id=1, uid=1)
+class TestEntity:
     id = Id()

tests/test_model.py

@@ -4,7 +4,7 @@
 
 def test_model():
     model = objectbox.Model()
-    model.add_entity(TestEntity)
+    model.entity(TestEntity)
 
     builder = objectbox.Builder()
     builder.model(model)