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