0.0.4 version

README.md

@@ -48,36 +48,75 @@ class AppCatalog(Catalog):
     """ :type: (objects.Provider) -> ObjectB """
 
 
-# Catalog injection into consumer class.
-class Consumer(object):
-    catalog = AppCatalog(AppCatalog.object_a,
-                         AppCatalog.object_b)
-
-    def return_a_b(self):
-        return (self.catalog.object_a(),
-                self.catalog.object_b())
-
-a1, b1 = Consumer().return_a_b()
-
-
 # Catalog static provides.
-a2 = AppCatalog.object_a()
-b2 = AppCatalog.object_b()
+a1, a2 = AppCatalog.object_a(), AppCatalog.object_a()
+b1, b2 = AppCatalog.object_b(), AppCatalog.object_b()
 
 # Some asserts.
 assert a1 is not a2
 assert b1 is not b2
-assert a1.db is a2.db is b1.db is b2.db
+assert a1.db is a2.db is b1.db is b2.db is AppCatalog.database()
+
+
+# Dependency injection (The Python Way) into class.
+class Consumer(object):
+
+    dependencies = AppCatalog(AppCatalog.object_a,
+                              AppCatalog.object_b)
+
+    def test(self):
+        a1 = self.dependencies.object_a()
+        a2 = self.dependencies.object_a()
+
+        b1 = self.dependencies.object_b()
+        b2 = self.dependencies.object_b()
+
+        # Some asserts.
+        assert a1 is not a2
+        assert b1 is not b2
+        assert a1.db is a2.db is b1.db is b2.db
+
+        try:
+            self.dependencies.database()
+        except AttributeError:
+            pass
+        else:
+            raise Exception('Database is not listed as a dependency')
+
+Consumer().test()
+
+
+# Dependency injection (The Python Way) into a callback.
+def consumer_callback(dependencies=AppCatalog(AppCatalog.object_a,
+                                              AppCatalog.object_b)):
+    a1 = dependencies.object_a()
+    a2 = dependencies.object_a()
+
+    b1 = dependencies.object_b()
+    b2 = dependencies.object_b()
+
+    # Some asserts.
+    assert a1 is not a2
+    assert b1 is not b2
+    assert a1.db is a2.db is b1.db is b2.db
+
+    try:
+        dependencies.database()
+    except AttributeError:
+        pass
+    else:
+        raise Exception('Database is not listed as a dependency')
 ```
 
-Example of injections using objects.catalog:
+Example of overriding object providers:
 
 ```python
 """
-Concept example of objects injections.
+Concept example of objects overrides.
 """
 
-from objects import Catalog, Singleton, NewInstance, InitArg, Attribute, inject
+
+from objects import Catalog, Singleton, NewInstance, InitArg, Attribute, overrides
 import sqlite3
 
 
@@ -87,6 +126,10 @@ class ObjectA(object):
         self.db = db
 
 
+class ObjectAMock(ObjectA):
+    pass
+
+
 # Catalog of objects providers.
 class AppCatalog(Catalog):
     """
@@ -103,57 +146,25 @@ class AppCatalog(Catalog):
     """ :type: (objects.Provider) -> ObjectA """
 
 
-# Class attributes injections.
-@inject(Attribute('a', AppCatalog.object_a))
-@inject(Attribute('database', AppCatalog.database))
-class Consumer(object):
+# Overriding AppCatalog by SandboxCatalog with some mocks.
+@overrides(AppCatalog)
+class SandboxCatalog(AppCatalog):
     """
-    Some consumer class with database dependency via attribute.
+    Sandbox objects catalog with some mocks.
     """
 
-    a = None
+    object_a = NewInstance(ObjectAMock,
+                           InitArg('db', AppCatalog.database))
     """ :type: (objects.Provider) -> ObjectA """
 
-    database = None
-    """ :type: (objects.Provider) -> sqlite3.Connection """
 
-    def tests(self):
-        a1, a2 = self.a(), self.a()
+# Catalog static provides.
+a1 = AppCatalog.object_a()
+a2 = AppCatalog.object_a()
 
-        assert a1 is not a2
-        assert a1.db is a2.db is self.database()
-
-
-consumer = Consumer()
-consumer.tests()
-
-
-# Class __init__ injections.
-@inject(InitArg('a1', AppCatalog.object_a))
-@inject(InitArg('a2', AppCatalog.object_a))
-@inject(InitArg('database', AppCatalog.database))
-class ConsumerWithInitArg(object):
-    """
-    Some consumer class with database dependency via init arg.
-    """
-
-    def __init__(self, a1, a2, database):
-        """
-        Initializer.
-
-        :param a1: ObjectA
-        :param a2: ObjectA
-        :param database: sqlite3.Connection
-        """
-        self.a1 = a1
-        self.a2 = a2
-        self.database = database
-
-    def tests(self):
-        assert self.a1 is not self.a2
-        assert self.a1.db is self.a2.db is self.database
-
-
-consumer = ConsumerWithInitArg()
-consumer.tests()
+# Some asserts.
+assert isinstance(a1, ObjectAMock)
+assert isinstance(a2, ObjectAMock)
+assert a1 is not a2
+assert a1.db is a2.db is AppCatalog.database()
 ```

VERSION

@@ -1 +1 @@
-0.0.3
+0.0.4

examples/concept.py

@@ -39,23 +39,61 @@ class AppCatalog(Catalog):
     """ :type: (objects.Provider) -> ObjectB """
 
 
-# Catalog injection into consumer class.
-class Consumer(object):
-    catalog = AppCatalog(AppCatalog.object_a,
-                         AppCatalog.object_b)
-
-    def return_a_b(self):
-        return (self.catalog.object_a(),
-                self.catalog.object_b())
-
-a1, b1 = Consumer().return_a_b()
-
-
 # Catalog static provides.
-a2 = AppCatalog.object_a()
-b2 = AppCatalog.object_b()
+a1, a2 = AppCatalog.object_a(), AppCatalog.object_a()
+b1, b2 = AppCatalog.object_b(), AppCatalog.object_b()
 
 # Some asserts.
 assert a1 is not a2
 assert b1 is not b2
-assert a1.db is a2.db is b1.db is b2.db
+assert a1.db is a2.db is b1.db is b2.db is AppCatalog.database()
+
+
+# Dependency injection (The Python Way) into class.
+class Consumer(object):
+
+    dependencies = AppCatalog(AppCatalog.object_a,
+                              AppCatalog.object_b)
+
+    def test(self):
+        a1 = self.dependencies.object_a()
+        a2 = self.dependencies.object_a()
+
+        b1 = self.dependencies.object_b()
+        b2 = self.dependencies.object_b()
+
+        # Some asserts.
+        assert a1 is not a2
+        assert b1 is not b2
+        assert a1.db is a2.db is b1.db is b2.db
+
+        try:
+            self.dependencies.database()
+        except AttributeError:
+            pass
+        else:
+            raise Exception('Database is not listed as a dependency')
+
+Consumer().test()
+
+
+# Dependency injection (The Python Way) into a callback.
+def consumer_callback(dependencies=AppCatalog(AppCatalog.object_a,
+                                              AppCatalog.object_b)):
+    a1 = dependencies.object_a()
+    a2 = dependencies.object_a()
+
+    b1 = dependencies.object_b()
+    b2 = dependencies.object_b()
+
+    # Some asserts.
+    assert a1 is not a2
+    assert b1 is not b2
+    assert a1.db is a2.db is b1.db is b2.db
+
+    try:
+        dependencies.database()
+    except AttributeError:
+        pass
+    else:
+        raise Exception('Database is not listed as a dependency')

examples/injections.py

@@ -1,83 +0,0 @@
-"""
-Concept example of objects injections.
-"""
-
-from objects import Catalog, Singleton, NewInstance, InitArg, Attribute, inject
-import sqlite3
-
-
-# Some example class.
-class ObjectA(object):
-    def __init__(self, db):
-        self.db = db
-
-
-# Catalog of objects providers.
-class AppCatalog(Catalog):
-    """
-    Objects catalog.
-    """
-
-    database = Singleton(sqlite3.Connection,
-                         InitArg('database', ':memory:'),
-                         Attribute('row_factory', sqlite3.Row))
-    """ :type: (objects.Provider) -> sqlite3.Connection """
-
-    object_a = NewInstance(ObjectA,
-                           InitArg('db', database))
-    """ :type: (objects.Provider) -> ObjectA """
-
-
-# Class attributes injections.
-@inject(Attribute('a', AppCatalog.object_a))
-@inject(Attribute('database', AppCatalog.database))
-class Consumer(object):
-    """
-    Some consumer class with database dependency via attribute.
-    """
-
-    a = None
-    """ :type: (objects.Provider) -> ObjectA """
-
-    database = None
-    """ :type: (objects.Provider) -> sqlite3.Connection """
-
-    def tests(self):
-        a1, a2 = self.a(), self.a()
-
-        assert a1 is not a2
-        assert a1.db is a2.db is self.database()
-
-
-consumer = Consumer()
-consumer.tests()
-
-
-# Class __init__ injections.
-@inject(InitArg('a1', AppCatalog.object_a))
-@inject(InitArg('a2', AppCatalog.object_a))
-@inject(InitArg('database', AppCatalog.database))
-class ConsumerWithInitArg(object):
-    """
-    Some consumer class with database dependency via init arg.
-    """
-
-    def __init__(self, a1, a2, database):
-        """
-        Initializer.
-
-        :param a1: ObjectA
-        :param a2: ObjectA
-        :param database: sqlite3.Connection
-        """
-        self.a1 = a1
-        self.a2 = a2
-        self.database = database
-
-    def tests(self):
-        assert self.a1 is not self.a2
-        assert self.a1.db is self.a2.db is self.database
-
-
-consumer = ConsumerWithInitArg()
-consumer.tests()

examples/overrides.py

@@ -0,0 +1,56 @@
+"""
+Concept example of objects overrides.
+"""
+
+
+from objects import Catalog, Singleton, NewInstance, InitArg, Attribute, overrides
+import sqlite3
+
+
+# Some example class.
+class ObjectA(object):
+    def __init__(self, db):
+        self.db = db
+
+
+class ObjectAMock(ObjectA):
+    pass
+
+
+# Catalog of objects providers.
+class AppCatalog(Catalog):
+    """
+    Objects catalog.
+    """
+
+    database = Singleton(sqlite3.Connection,
+                         InitArg('database', ':memory:'),
+                         Attribute('row_factory', sqlite3.Row))
+    """ :type: (objects.Provider) -> sqlite3.Connection """
+
+    object_a = NewInstance(ObjectA,
+                           InitArg('db', database))
+    """ :type: (objects.Provider) -> ObjectA """
+
+
+# Overriding AppCatalog by SandboxCatalog with some mocks.
+@overrides(AppCatalog)
+class SandboxCatalog(AppCatalog):
+    """
+    Sandbox objects catalog with some mocks.
+    """
+
+    object_a = NewInstance(ObjectAMock,
+                           InitArg('db', AppCatalog.database))
+    """ :type: (objects.Provider) -> ObjectA """
+
+
+# Catalog static provides.
+a1 = AppCatalog.object_a()
+a2 = AppCatalog.object_a()
+
+# Some asserts.
+assert isinstance(a1, ObjectAMock)
+assert isinstance(a2, ObjectAMock)
+assert a1 is not a2
+assert a1.db is a2.db is AppCatalog.database()

objects/__init__.py

@@ -2,17 +2,17 @@
 `Objects` library.
 """
 
-from .catalog import Catalog
+from .catalog import Catalog, overrides
 from .providers import (Provider, NewInstance, Singleton, Class, Object,
                         Function, Value)
-from .injections import InitArg, Attribute, Method, inject
+from .injections import InitArg, Attribute, Method, uses
 
 
-__all__ = ['Catalog',
+__all__ = ['Catalog', 'overrides',
 
            # Providers
            'Provider', 'NewInstance', 'Singleton', 'Class',
            'Object', 'Function', 'Value',
 
            # Injections
-           'InitArg', 'Attribute', 'Method', 'inject']
+           'InitArg', 'Attribute', 'Method', 'uses']

objects/catalog.py

@@ -14,19 +14,58 @@ class Catalog(object):
         """
         Initializer.
         """
-        self._clean_unused_providers(used_providers)
+        self.__used_providers__ = set(used_providers)
 
-    def _clean_unused_providers(self, used_providers):
+    def __getattribute__(self, item):
         """
-        Sets every catalog's provider in None except of `used_providers` list.
+        Returns providers.
 
-        :param list|tuple|set used_providers:
+        :param item:
         :return:
         """
-        used_providers = set(used_providers)
-        for attribute_name in set(dir(self.__class__)) - set(dir(Catalog)):
-            provider = getattr(self, attribute_name)
+        attribute = super(Catalog, self).__getattribute__(item)
+        if item in ('__used_providers__',):
+            return attribute
+
+        if attribute not in self.__used_providers__:
+            raise AttributeError('Provider \'{}\' is not listed in '
+                                 'dependencies'.format(item))
+        return attribute
+
+    @classmethod
+    def __all_providers__(cls):
+        """
+        Returns set of all class providers.
+        """
+        providers = set()
+        for attr_name in set(dir(cls)) - set(dir(Catalog)):
+            provider = getattr(cls, attr_name)
             if not isinstance(provider, Provider):
                 continue
-            if provider not in used_providers:
-                setattr(self, attribute_name, None)
+            providers.add((attr_name, provider))
+        return providers
+
+    @classmethod
+    def __override___(cls, overriding):
+        """
+        Overrides current catalog providers by overriding catalog providers.
+
+        :param overriding: Catalog
+        """
+        overriden = overriding.__all_providers__() - cls.__all_providers__()
+        for name, provider in overriden:
+            overridden_provider = getattr(cls, name)
+            overridden_provider.__override__(provider)
+
+
+def overrides(catalog):
+    """
+    Catalog overriding decorator.
+
+    :param catalog:
+    :return:
+    """
+    def decorator(overriding_catalog):
+        catalog.__override___(overriding_catalog)
+        return overriding_catalog
+    return decorator

objects/injections.py

@@ -46,25 +46,12 @@ class Method(Injection):
     """
 
 
-def inject(injection):
+def uses(provider):
     """
-    Injection decorator.
+    Providers usage decorator.
     """
-    def decorator(callback_or_cls):
-        if isclass(callback_or_cls):
-            cls = callback_or_cls
-            if isinstance(injection, Attribute):
-                setattr(cls, injection.name, injection.injectable)
-            elif isinstance(injection, InitArg):
-                cls.__init__ = decorator(cls.__init__)
+    def decorator(cls):
+        catalog = getattr(cls, 'catalog')
+        # catalog.__add__provider__(provider)
         return cls
-        else:
-            callback = callback_or_cls
-
-            @wraps(callback)
-            def wrapped(*args, **kwargs):
-                if injection.name not in kwargs:
-                    kwargs[injection.name] = injection.value
-                return callback(*args, **kwargs)
-            return wrapped
     return decorator

objects/providers.py

@@ -11,6 +11,13 @@ class Provider(object):
     """
 
     __is_objects_provider__ = True
+    __overridden_by__ = list()
+
+    def __init__(self):
+        """
+        Initializer.
+        """
+        self.__overridden_by__ = list()
 
     def __call__(self, *args, **kwargs):
         """
@@ -18,6 +25,12 @@ class Provider(object):
         """
         raise NotImplementedError()
 
+    def __override__(self, provider):
+        """
+        Overrides provider with another provider.
+        """
+        self.__overridden_by__.append(provider)
+
 
 def prepare_injections(injections):
     """
@@ -48,11 +61,15 @@ class NewInstance(Provider):
         self.init_injections = fetch_injections(injections, InitArg)
         self.attribute_injections = fetch_injections(injections, Attribute)
         self.method_injections = fetch_injections(injections, Method)
+        super(NewInstance, self).__init__()
 
     def __call__(self, *args, **kwargs):
         """
         Returns provided instance.
         """
+        if self.__overridden_by__:
+            return self.__overridden_by__[-1].__call__(*args, **kwargs)
+
         init_injections = prepare_injections(self.init_injections)
         init_injections = dict(init_injections)
         init_injections.update(kwargs)
@@ -102,11 +119,14 @@ class _StaticProvider(Provider):
         Initializer.
         """
         self.provides = provides
+        super(_StaticProvider, self).__init__()
 
     def __call__(self):
         """
         Returns provided instance.
         """
+        if self.__overridden_by__:
+            return self.__overridden_by__[-1].__call__()
         return self.provides