so_magic.data.features.phi.PhiFunctionRegistry.get_instance() - Code Metrics - Inspection of "Release v0.5.1" - boromir674/so-magic - Measure and Improve Code Quality continuously with Scrutinizer

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Pull Request — master (#22)

by Konstantinos

created 2021-05-13 13:09 UTC

PhiFunctionRegistry.get_instance() A

↳ Parent: so_magic.data.features.phi

Complexity

Conditions

Size

Total Lines	8
Code Lines	3

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	1
eloc	3
nop	0
dl	0
loc	8
rs	10
c	0
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f	0

"""This module is responsible to provide a formal way of registering phi functions
at runtime. See the 'PhiFunctionRegistrator' class and its 'register' decorator method
"""
import logging
import inspect
from typing import Callable
from so_magic.utils import Singleton, ObjectRegistry, Subject

logger = logging.getLogger(__name__)


class PhiFunctionRegistry(Singleton, ObjectRegistry):
    """A Singleton dict-like object registry for phi functions.

    Use this class to create a singleton object (instance of this class) that
    acts as a storage for phi function objects.
    """
    def __new__(cls, *args, **kwargs):
        """Create a new (singleton) instance and initialize an empty registry.

        Returns:
            PhiFunctionRegistry: the reference to the singleton object (instance)
        """
        phi_function_registry = Singleton.__new__(cls, *args, **kwargs)
        phi_function_registry = ObjectRegistry(getattr(phi_function_registry, 'objects', {}))
        return phi_function_registry

    @staticmethod
    def get_instance():
        """Get the singleton object (instance).

        Returns:
            PhiFunctionRegistry: the reference to the singleton object (instance)
        """
        return PhiFunctionRegistry()


phi_registry = PhiFunctionRegistry()


class PhiFunctionMetaclass(type):
    """Class type with a single broadcasting (notifies listeners) facility.

    Classes using this class as metaclass, obtain a single broadcasting facility
    as a class attribute. The class attribute is called 'subject' can be referenced
    as any class attribute.

    Example:
        class MyExampleClass(metaclass=PhiFunctionMetaclass):
            pass

        instance_object_1 = MyExampleClass()
        instance_object_2 = MyExampleClass()
        assert id(MyExampleClass.subject) == id(instance_object_1.subject) == id(instance_object_2.subject)
    """
    def __new__(mcs, *args, **kwargs):
        """Create a new class type object and set the 'subject' attribute to a new Subject instance; the broadcaster.

        Returns:
            PhiFunctionMetaclass: the new class type object
        """
        phi_function_class = super().__new__(mcs, *args, **kwargs)
        phi_function_class.subject = Subject([])
        return phi_function_class


class PhiFunctionRegistrator(metaclass=PhiFunctionMetaclass):
    """Add phi functions to the registry and notify observers/listeners.

    This class provides the 'register' decorator, that client can use to decorate either functions (defined with the
    def python special word), or classes (defined with the python class special word).
    """

    # NICE TO HAVE: make the decorator work without parenthesis
    @classmethod
    def register(cls, phi_name=''):
        """Add a new phi function to phi function registry and notify listeners/observers.

        Use this decorator around either a callable function (defined with the 'def' python special word) or a class
        with a takes-no-arguments (or all-optional-arguments) constructor and a __call__ magic method.

        All phi functions are expected to be registered with a __name__ and a __doc__ attribute.

        You can select your custom phi_name under which to register the phi function or default to an automatic
        determination of the phi_name to use.

        Automatic determination of phi_name is done by examining either the __name__ attribute of the function or the
        class name of the class.

        Example:

            >>> from so_magic.data.features.phi import PhiFunctionRegistry, PhiFunctionRegistrator

            >>> registered_phis = PhiFunctionRegistry()

            >>> @PhiFunctionRegistrator.register()
            ... def f1(x):
            ...  return x * 2
            Registering input function f1 as phi function, at key f1.

            >>> input_value = 5
            >>> print(f"{input_value} * 2 = {registered_phis.get('f1')(input_value)}")
            5 * 2 = 10

            >>> @PhiFunctionRegistrator.register()
            ... class f2:
            ...  def __call__(self, data, **kwargs):
            ...   return data + 5
            Registering input class f2 instance as phi function, at key f2.

            >>> input_value = 1
            >>> print(f"{input_value} + 5 = {registered_phis.get('f2')(input_value)}")
            1 + 5 = 6

            >>> @PhiFunctionRegistrator.register('f3')
            ... class MyCustomClass:
            ...  def __call__(self, data, **kwargs):
            ...   return data + 1
            Registering input class MyCustomClass instance as phi function, at key f3.

            >>> input_value = 3
            >>> print(f"{input_value} + 1 = {registered_phis.get('f3')(input_value)}")
            3 + 1 = 4

        Args:
            phi_name (str, optional): custom name to register the phi function. Defaults to automatic computation.
        """
        def wrapper(a_callable):
            """Add a callable object to the phi function registry and preserve info for __name__ and __doc__ attributes.

            The callable object should either be function (defined with def) or a class (defined with class). In case of
            a class the class must have a constructor that takes no arguments (or all arguments are optional) and a
            __call__ magic method.

            Registers the callable as a phi function under the given or automatically computed name, makes sure the
            __name__ and __doc__ attributes preserve information and notifies potential listeners/observers.

            Args:
                a_callable (Callable): the object (function or class) to register as phi function
            """
            if hasattr(a_callable, '__code__'):  # it is a function (def func_name ..)
                logging.info("Registering input function %s as phi function.", a_callable.__code__.co_name)
                key = phi_name if phi_name else cls.get_name(a_callable)
                print(f"Registering input function {a_callable.__code__.co_name} as phi function, at key {key}.")
                cls._register(a_callable, key)
            else:
                if not hasattr(a_callable, '__call__'):
                    raise RuntimeError("Expected an class definition with a '__call__' instance method defined 1."
                                       f" Got {type(a_callable)}")
                members = inspect.getmembers(a_callable)
                if ('__call__', a_callable.__call__) not in members:
                    raise RuntimeError("Expected an class definition with a '__call__' instance method defined 2."
                                       f" Got {type(a_callable)}")
                instance = a_callable()
                instance.__name__ = a_callable.__name__
                instance.__doc__ = a_callable.__call__.__doc__
                key = phi_name if phi_name else cls.get_name(instance)
                print(f"Registering input class {a_callable.__name__} instance as phi function, at key {key}.")
                cls._register(instance, key)
            return a_callable
        return wrapper

    @classmethod
    def _register(cls, a_callable, key_name):
        """Register a callable as phi function and notify potential listeners/observers.

        The phi function is registered under the given key_name or in case of None the name is automatically computed
        based on the input callable.

        Args:
            a_callable (Callable): the callable that holds the business logic of the phi function
            key_name (str, optional): custom phi name. Defaults to None, which means automatic determination of the name
        """
        phi_registry.add(key_name, a_callable)
        cls.subject.name = key_name
        cls.subject.state = a_callable
        cls.subject.notify()

    @staticmethod
    def get_name(a_callable: Callable):
        """Get the 'name' of the input callable object

        Args:
            a_callable (Callable): a callable object to get its name

        Returns:
            str: the name of the callable object
        """
        if hasattr(a_callable, 'name'):
            return a_callable.name
        if hasattr(a_callable, '__code__') and hasattr(a_callable.__code__, 'co_name'):
            return a_callable.__code__.co_name
        if hasattr(type(a_callable), 'name'):
            return type(a_callable).name
        if hasattr(type(a_callable), '__name__'):
            return type(a_callable).__name__
        # TODO replace below line with a raise Exception
        # we want to cause an error when we fail to get a sensible string name
        return ''


if __name__ == '__main__':
    reg1 = PhiFunctionRegistry()
    reg2 = PhiFunctionRegistry()
    reg3 = PhiFunctionRegistry.get_instance()

    assert id(reg1) == id(reg2) == id(reg3)

    @PhiFunctionRegistrator.register
    def example():
        """Inherited Docstring"""
        print('Called example function')

    example()

    print(example.__name__)
    print('--')
    print(example.__doc__)

    reg1.get('example')()


1			"""This module is responsible to provide a formal way of registering phi functions
2			at runtime. See the 'PhiFunctionRegistrator' class and its 'register' decorator method
3			"""
4			import logging
5			import inspect
6			from typing import Callable
7			from so_magic.utils import Singleton, ObjectRegistry, Subject
8
9			logger = logging.getLogger(__name__)
10
11
12			class PhiFunctionRegistry(Singleton, ObjectRegistry):
13			"""A Singleton dict-like object registry for phi functions.
14
15			Use this class to create a singleton object (instance of this class) that
16			acts as a storage for phi function objects.
17			"""
18			def __new__(cls, args, *kwargs):
19			"""Create a new (singleton) instance and initialize an empty registry.
20
21			Returns:
22			PhiFunctionRegistry: the reference to the singleton object (instance)
23			"""
24			phi_function_registry = Singleton.__new__(cls, args, *kwargs)
25			phi_function_registry = ObjectRegistry(getattr(phi_function_registry, 'objects', {}))
26			return phi_function_registry
27
28			@staticmethod
29			def get_instance():
30			"""Get the singleton object (instance).
31
32			Returns:
33			PhiFunctionRegistry: the reference to the singleton object (instance)
34			"""
35			return PhiFunctionRegistry()
36
37
38			phi_registry = PhiFunctionRegistry()
39
40
41			class PhiFunctionMetaclass(type):
42			"""Class type with a single broadcasting (notifies listeners) facility.
43
44			Classes using this class as metaclass, obtain a single broadcasting facility
45			as a class attribute. The class attribute is called 'subject' can be referenced
46			as any class attribute.
47
48			Example:
49			class MyExampleClass(metaclass=PhiFunctionMetaclass):
50			pass
51
52			instance_object_1 = MyExampleClass()
53			instance_object_2 = MyExampleClass()
54			assert id(MyExampleClass.subject) == id(instance_object_1.subject) == id(instance_object_2.subject)
55			"""
56			def __new__(mcs, args, *kwargs):
57			"""Create a new class type object and set the 'subject' attribute to a new Subject instance; the broadcaster.
58
59			Returns:
60			PhiFunctionMetaclass: the new class type object
61			"""
62			phi_function_class = super().__new__(mcs, args, *kwargs)
63			phi_function_class.subject = Subject([])
64			return phi_function_class
65
66
67			class PhiFunctionRegistrator(metaclass=PhiFunctionMetaclass):
68			"""Add phi functions to the registry and notify observers/listeners.
69
70			This class provides the 'register' decorator, that client can use to decorate either functions (defined with the
71			def python special word), or classes (defined with the python class special word).
72			"""
73
74			# NICE TO HAVE: make the decorator work without parenthesis
75			@classmethod
76			def register(cls, phi_name=''):
77			"""Add a new phi function to phi function registry and notify listeners/observers.
78
79			Use this decorator around either a callable function (defined with the 'def' python special word) or a class
80			with a takes-no-arguments (or all-optional-arguments) constructor and a __call__ magic method.
81
82			All phi functions are expected to be registered with a __name__ and a __doc__ attribute.
83
84			You can select your custom phi_name under which to register the phi function or default to an automatic
85			determination of the phi_name to use.
86
87			Automatic determination of phi_name is done by examining either the __name__ attribute of the function or the
88			class name of the class.
89
90			Example:
91
92			>>> from so_magic.data.features.phi import PhiFunctionRegistry, PhiFunctionRegistrator
93
94			>>> registered_phis = PhiFunctionRegistry()
95
96			>>> @PhiFunctionRegistrator.register()
97			... def f1(x):
98			... return x * 2
99			Registering input function f1 as phi function, at key f1.
100
101			>>> input_value = 5
102			>>> print(f"{input_value} * 2 = {registered_phis.get('f1')(input_value)}")
103			5 * 2 = 10
104
105			>>> @PhiFunctionRegistrator.register()
106			... class f2:
107			... def __call__(self, data, **kwargs):
108			... return data + 5
109			Registering input class f2 instance as phi function, at key f2.
110
111			>>> input_value = 1
112			>>> print(f"{input_value} + 5 = {registered_phis.get('f2')(input_value)}")
113			1 + 5 = 6
114
115			>>> @PhiFunctionRegistrator.register('f3')
116			... class MyCustomClass:
117			... def __call__(self, data, **kwargs):
118			... return data + 1
119			Registering input class MyCustomClass instance as phi function, at key f3.
120
121			>>> input_value = 3
122			>>> print(f"{input_value} + 1 = {registered_phis.get('f3')(input_value)}")
123			3 + 1 = 4
124
125			Args:
126			phi_name (str, optional): custom name to register the phi function. Defaults to automatic computation.
127			"""
128			def wrapper(a_callable):
129			"""Add a callable object to the phi function registry and preserve info for __name__ and __doc__ attributes.
130
131			The callable object should either be function (defined with def) or a class (defined with class). In case of
132			a class the class must have a constructor that takes no arguments (or all arguments are optional) and a
133			__call__ magic method.
134
135			Registers the callable as a phi function under the given or automatically computed name, makes sure the
136			__name__ and __doc__ attributes preserve information and notifies potential listeners/observers.
137
138			Args:
139			a_callable (Callable): the object (function or class) to register as phi function
140			"""
141			if hasattr(a_callable, '__code__'): # it is a function (def func_name ..)
142			logging.info("Registering input function %s as phi function.", a_callable.__code__.co_name)
143			key = phi_name if phi_name else cls.get_name(a_callable)
144			print(f"Registering input function {a_callable.__code__.co_name} as phi function, at key {key}.")
145			cls._register(a_callable, key)
146			else:
147			if not hasattr(a_callable, '__call__'):
148			raise RuntimeError("Expected an class definition with a '__call__' instance method defined 1."
149			f" Got {type(a_callable)}")
150			members = inspect.getmembers(a_callable)
151			if ('__call__', a_callable.__call__) not in members:
152			raise RuntimeError("Expected an class definition with a '__call__' instance method defined 2."
153			f" Got {type(a_callable)}")
154			instance = a_callable()
155			instance.__name__ = a_callable.__name__
156			instance.__doc__ = a_callable.__call__.__doc__
157			key = phi_name if phi_name else cls.get_name(instance)
158			print(f"Registering input class {a_callable.__name__} instance as phi function, at key {key}.")
159			cls._register(instance, key)
160			return a_callable
161			return wrapper
162
163			@classmethod
164			def _register(cls, a_callable, key_name):
165			"""Register a callable as phi function and notify potential listeners/observers.
166
167			The phi function is registered under the given key_name or in case of None the name is automatically computed
168			based on the input callable.
169
170			Args:
171			a_callable (Callable): the callable that holds the business logic of the phi function
172			key_name (str, optional): custom phi name. Defaults to None, which means automatic determination of the name
173			"""
174			phi_registry.add(key_name, a_callable)
175			cls.subject.name = key_name
176			cls.subject.state = a_callable
177			cls.subject.notify()
178
179			@staticmethod
180			def get_name(a_callable: Callable):
181			"""Get the 'name' of the input callable object
182
183			Args:
184			a_callable (Callable): a callable object to get its name
185
186			Returns:
187			str: the name of the callable object
188			"""
189			if hasattr(a_callable, 'name'):
190			return a_callable.name
191			if hasattr(a_callable, '__code__') and hasattr(a_callable.__code__, 'co_name'):
192			return a_callable.__code__.co_name
193			if hasattr(type(a_callable), 'name'):
194			return type(a_callable).name
195			if hasattr(type(a_callable), '__name__'):
196			return type(a_callable).__name__
197			# TODO replace below line with a raise Exception
198			# we want to cause an error when we fail to get a sensible string name
199			return ''
200
201
202			if __name__ == '__main__':
203			reg1 = PhiFunctionRegistry()
204			reg2 = PhiFunctionRegistry()
205			reg3 = PhiFunctionRegistry.get_instance()
206
207			assert id(reg1) == id(reg2) == id(reg3)
208
209			@PhiFunctionRegistrator.register
210			def example():
211			"""Inherited Docstring"""
212			print('Called example function')
213
214			example()
215
216			print(example.__name__)
217			print('--')
218			print(example.__doc__)
219
220			reg1.get('example')()
221

boromir674 / so-magic

Pull Request — master (#22)

PhiFunctionRegistry.get_instance() A

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