75 lines
1.9 KiB
ReStructuredText
75 lines
1.9 KiB
ReStructuredText
Factory of Factories pattern
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============================
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This example demonstrates "Factory of Factories" pattern.
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The idea of the pattern is in creating a ``Factory`` that creates another ``Factory`` and adds
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additional arguments.
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.. code-block:: python
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base_factory = providers.Factory(
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providers.Factory
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SomeClass,
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base_argument=1,
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)
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concrete_factory = providers.Factory(
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OtherClass,
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instance=base_factory(extra_argument=1),
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)
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if __name__ == '__main__':
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instance = concrete_factory()
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# Same as: # instance = SomeClass(base_argument=1, extra_argument=2)
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Sample code
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-----------
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Listing of the pattern example:
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.. literalinclude:: ../../examples/miniapps/factory-patterns/factory_of_factories.py
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:language: python
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Arguments priority
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------------------
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Passing of the arguments works the same way like for any other :ref:`factory-provider`.
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.. code-block:: python
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# 1. Keyword arguments of upper level factory are added to lower level factory
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factory_of_dict_factories = providers.Factory(
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providers.Factory,
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dict,
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arg1=1,
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)
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dict_factory = factory_of_dict_factories(arg2=2)
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print(dict_factory()) # prints: {'arg1': 1, 'arg2': 2}
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# 2. Keyword arguments of upper level factory have priority
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factory_of_dict_factories = providers.Factory(
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providers.Factory,
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dict,
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arg1=1,
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)
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dict_factory = factory_of_dict_factories(arg1=2)
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print(dict_factory()) # prints: {'arg1': 2}
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# 3. Keyword arguments provided from context have the most priority
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factory_of_dict_factories = providers.Factory(
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providers.Factory,
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dict,
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arg1=1,
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)
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dict_factory = factory_of_dict_factories(arg1=2)
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print(dict_factory(arg1=3)) # prints: {'arg1': 3}
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Credits
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-------
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The "Factory of Factories" pattern was suggested by the ``Dependency Injector`` users.
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.. disqus::
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