Add docs for usage of @inject decorator with classes

docs/advanced_usage/index.rst

@@ -18,10 +18,23 @@ called to provide injectable values.
 
 Example:
 
-.. literalinclude:: ../../examples/advanced_usage/inject_decorator_simple.py
+.. literalinclude:: ../../examples/advanced_usage/inject_simple.py
    :language: python
 
 Example of usage ``@di.inject()`` decorator with Flask:
 
-.. literalinclude:: ../../examples/advanced_usage/inject_decorator_flask.py
+.. literalinclude:: ../../examples/advanced_usage/inject_flask.py
+   :language: python
+
+
+@inject decorator with classes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+``@di.inject()`` could be applied for classes. In such case, it will look for 
+class's ``__init__()`` method and pass injection to it. If decorated class has 
+no ``__init__()`` method, appropriate ``di.Error`` will be raised.
+
+Example of usage ``@di.inject()`` with Flask class-based view:
+
+.. literalinclude:: ../../examples/advanced_usage/inject_flask_class_based.py
    :language: python

docs/main/changelog.rst

@@ -11,7 +11,7 @@ follows `Semantic versioning`_
 Development version
 -------------------
 
-- No featues.
+- Add ``@di.inject`` functionality for decorating classes.
 
 0.9.5
 -----

examples/advanced_usage/inject_flask_class_based.py

@@ -0,0 +1,42 @@
+"""`@di.inject()` decorator with classes example."""
+
+import sqlite3
+import flask
+import flask.views
+import dependency_injector as di
+
+
+database = di.Singleton(sqlite3.Connection,
+                        database=':memory:',
+                        timeout=30,
+                        detect_types=True,
+                        isolation_level='EXCLUSIVE')
+
+app = flask.Flask(__name__)
+
+
+@di.inject(database=database)
+@di.inject(some_setting=777)
+class HelloView(flask.views.View):
+
+    """Example flask class-based view."""
+
+    def __init__(self, database, some_setting):
+        """Initializer."""
+        self.database = database
+        self.some_setting = some_setting
+
+    def dispatch_request(self):
+        """Handle example request."""
+        one = self.database.execute('SELECT 1').fetchone()[0]
+        one *= self.some_setting
+        return 'Query returned {0}, db connection {1}'.format(one, database)
+
+
+app.add_url_rule('/', view_func=HelloView.as_view('hello_view'))
+
+if __name__ == '__main__':
+    app.run()
+
+# Example output of "GET / HTTP/1.1" is:
+# Query returned 777, db connection <sqlite3.Connection object at 0x1057e4030>