Merge pull request #174 from ets-labs/feature/factory-aggregate

Create FactoryAggregate provider

docs/main/changelog.rst

@@ -9,8 +9,9 @@ follows `Semantic versioning`_
 
 Development version
 -------------------
+- Add ``FactoryAggregate`` provider.
 - Add support of six 1.11.0.
-- Regenerate C sources using Cython 0.27.
+- Regenerate C sources using Cython 0.27.1.
 
 3.6.1
 -----

docs/providers/factory.rst

@@ -147,4 +147,38 @@ Listing of ``example.py``:
    :language: python
    :linenos:
 
+Factory aggregate providers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+:py:class:`FactoryAggregate` provider is a special type of provider that 
+aggregates other :py:class:`Factory` providers.
+
+.. note::
+
+    :py:class:`FactoryAggregate` is not overridable. Calling of 
+    :py:meth:`FactoryAggregate.override` will result in raising of an 
+    expection.
+
+Next prototype might be the best demonstration of 
+:py:class:`FactoryAggregate` features:
+
+.. literalinclude:: ../../examples/providers/factory_aggregate/prototype.py
+   :language: python
+   :linenos:
+
+Example below shows one of the :py:class:`FactoryAggregate` use cases, when 
+concrete implementation (game) must be selected based on dynamic input (CLI). 
+
+Listing of ``games.py``:
+
+.. literalinclude:: ../../examples/providers/factory_aggregate/games.py
+   :language: python
+   :linenos:
+
+Listing of ``example.py``:
+
+.. literalinclude:: ../../examples/providers/factory_aggregate/example.py
+   :language: python
+   :linenos:
+
 .. disqus::

examples/providers/factory_aggregate/example.py

@@ -0,0 +1,29 @@
+"""`FactoryAggregate` providers example."""
+
+import sys
+
+import dependency_injector.providers as providers
+
+from games import Chess, Checkers, Ludo
+
+
+game_factory = providers.FactoryAggregate(chess=providers.Factory(Chess),
+                                          checkers=providers.Factory(Checkers),
+                                          ludo=providers.Factory(Ludo))
+
+if __name__ == '__main__':
+    game_type = sys.argv[1].lower()
+    player1 = sys.argv[2].capitalize()
+    player2 = sys.argv[3].capitalize()
+
+    selected_game = game_factory(game_type, player1, player2)
+    selected_game.play()
+
+    # $ python example.py chess John Jane
+    # John and Jane are playing chess
+    #
+    # $ python example.py checkers John Jane
+    # John and Jane are playing checkers
+    #
+    # $ python example.py ludo John Jane
+    # John and Jane are playing ludo

examples/providers/factory_aggregate/games.py

@@ -0,0 +1,27 @@
+"""Example games module."""
+
+
+class Game(object):
+    """Base game class."""
+
+    def __init__(self, player1, player2):
+        """Initializer."""
+        self.player1 = player1
+        self.player2 = player2
+
+    def play(self):
+        """Play game."""
+        print('{0} and {1} are playing {2}'.format(
+            self.player1, self.player2, self.__class__.__name__.lower()))
+
+
+class Chess(Game):
+    """Chess game."""
+
+
+class Checkers(Game):
+    """Checkers game."""
+
+
+class Ludo(Game):
+    """Ludo game."""

examples/providers/factory_aggregate/prototype.py

@@ -0,0 +1,17 @@
+"""FactoryAggregate provider prototype."""
+
+
+class FactoryAggregate(object):
+    """FactoryAggregate provider prototype."""
+
+    def __init__(self, **factories):
+        """Initializer."""
+        self.factories = factories
+
+    def __call__(self, factory_name, *args, **kwargs):
+        """Create object."""
+        return self.factories[factory_name](*args, **kwargs)
+
+    def __getattr__(self, factory_name):
+        """Return factory with specified name."""
+        return self.factories[factory_name]

requirements-dev.txt

@@ -1,4 +1,4 @@
-cython==0.27
+cython==0.27.1
 tox
 unittest2
 coverage