""" Scoped provider examples. """ from objects import AbstractCatalog from objects.providers import ( Singleton, Scoped, ) from objects.injections import ( InitArg, Attribute, ) import sqlite3 class ObjectA(object): def __init__(self, db): self.db = db # Catalog of objects providers. class Catalog(AbstractCatalog): """ Objects catalog. """ database = Singleton(sqlite3.Connection, InitArg('database', ':memory:'), Attribute('row_factory', sqlite3.Row)) """ :type: (objects.Provider) -> sqlite3.Connection """ object_a = Scoped(ObjectA, InitArg('db', database)) """ :type: (objects.Provider) -> ObjectA """ # Making scope using `with` statement. with Catalog.object_a as object_a_provider: object_a1 = object_a_provider() object_a2 = object_a_provider() assert object_a1 is object_a2 assert object_a1.db is object_a2.db # Making another one scope using `with` statement. with Catalog.object_a as object_a_provider: object_a3 = object_a_provider() object_a4 = object_a_provider() assert object_a3 is object_a4 assert object_a3.db is object_a4.db assert (object_a1 is not object_a3) and \ (object_a1 is not object_a4) assert (object_a2 is not object_a3) and \ (object_a2 is not object_a4) # Making one more scope using provider methods. Catalog.object_a.in_scope() object_a5 = Catalog.object_a() object_a6 = Catalog.object_a() Catalog.object_a.out_of_scope() assert object_a5 is object_a6 assert object_a5.db is object_a6.db assert (object_a1 is not object_a3) and \ (object_a1 is not object_a4) and \ (object_a1 is not object_a5) and \ (object_a1 is not object_a6) assert (object_a2 is not object_a3) and \ (object_a2 is not object_a4) and \ (object_a2 is not object_a5) and \ (object_a2 is not object_a6)