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72 lines
1.7 KiB
Python
72 lines
1.7 KiB
Python
"""Concept example of `Objects`."""
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from objects.catalog import AbstractCatalog
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from objects.providers import Singleton
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from objects.providers import NewInstance
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from objects.injections import KwArg
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from objects.injections import Attribute
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from objects.decorators import inject
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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 ObjectB(object):
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"""Example class ObjectB, that has dependencies on ObjectA and database."""
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def __init__(self, a, db):
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"""Initializer."""
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self.a = a
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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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KwArg('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 = NewInstance(ObjectA,
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KwArg('db', database))
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""":type: (objects.Provider) -> ObjectA"""
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object_b = NewInstance(ObjectB,
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KwArg('a', object_a),
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KwArg('db', database))
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""":type: (objects.Provider) -> ObjectB"""
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# Catalog static provides.
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a1, a2 = Catalog.object_a(), Catalog.object_a()
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b1, b2 = Catalog.object_b(), Catalog.object_b()
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assert a1 is not a2
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assert b1 is not b2
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assert a1.db is a2.db is b1.db is b2.db is Catalog.database()
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# Example of inline injections.
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@inject(KwArg('a', Catalog.object_a))
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@inject(KwArg('b', Catalog.object_b))
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@inject(KwArg('database', Catalog.database))
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def example(a, b, database):
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assert a.db is b.db is database is Catalog.database()
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example()
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