Implement add_injection() for Callable, Factory & Singleton providers

dependency_injector/providers/callable.py

@@ -76,8 +76,10 @@ class Callable(Provider):
 
         self.provides = provides
 
-        self.args = _parse_args_injections(args)
-        self.kwargs = _parse_kwargs_injections(args, kwargs)
+        self.args = tuple()
+        self.kwargs = tuple()
+
+        self.add_injections(*args, **kwargs)
 
         super(Callable, self).__init__()
 
@@ -89,6 +91,18 @@ class Callable(Provider):
         """
         return self.args + self.kwargs
 
+    def add_injections(self, *args, **kwargs):
+        """Add provider injections.
+
+        :param args: Tuple of injections.
+        :type args: tuple
+
+        :param kwargs: Dictionary of injections.
+        :type kwargs: dict
+        """
+        self.args += _parse_args_injections(args)
+        self.kwargs += _parse_kwargs_injections(args, kwargs)
+
     def _provide(self, *args, **kwargs):
         """Return provided instance.
 

dependency_injector/providers/creational.py

@@ -106,13 +106,8 @@ class Factory(Callable):
             raise Error('{0} can provide only {1} instances'.format(
                 self.__class__, self.__class__.provided_type))
 
-        self.attributes = tuple(injection
-                                for injection in args
-                                if is_attribute_injection(injection))
-
-        self.methods = tuple(injection
-                             for injection in args
-                             if is_method_injection(injection))
+        self.attributes = tuple()
+        self.methods = tuple()
 
         super(Factory, self).__init__(provides, *args, **kwargs)
 
@@ -126,6 +121,25 @@ class Factory(Callable):
         """
         return self.args + self.kwargs + self.attributes + self.methods
 
+    def add_injections(self, *args, **kwargs):
+        """Add provider injections.
+
+        :param args: Tuple of injections.
+        :type args: tuple
+
+        :param kwargs: Dictionary of injections.
+        :type kwargs: dict
+        """
+        self.attributes += tuple(injection
+                                 for injection in args
+                                 if is_attribute_injection(injection))
+
+        self.methods += tuple(injection
+                              for injection in args
+                              if is_method_injection(injection))
+
+        super(Factory, self).add_injections(*args, **kwargs)
+
     def _provide(self, *args, **kwargs):
         """Return provided instance.
 

docs/main/changelog.rst

@@ -11,6 +11,12 @@ Development version
 -------------------
 - No features.
 
+1.17.0
+------
+- Add ``add_injections()`` method to ``Callable``, ``DelegatedCallable``, 
+  ``Factory``, ``DelegatedFactory``, ``Singleton`` and ``DelegatedSingleton`` 
+  providers.
+
 1.16.8
 ------
 - Fix some typos in introduction section of documentation.