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""" |
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PRIVATE MODULE: do not import (from) it directly. |
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4
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This module contains the ``StateHolder`` class and the default ``StateHolder`` |
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instance. |
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""" |
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from typing import Optional |
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import jacked |
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class Container: |
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""" |
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An instance of ``Container`` holds registered injectables and can be used |
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to inject from. |
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""" |
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def __init__(self): |
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""" |
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Constructor. |
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""" |
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self._injectables = list() |
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self._subjects = set() |
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self._instances = dict() |
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def register(self, injectable: 'jacked.Injectable'): |
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""" |
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Register the given ``Injectable`` to this ``Container``. |
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:param injectable: the ``Injectable`` that is to be registered. |
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:return: None. |
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""" |
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if injectable.name not in self._subjects: |
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self._injectables.append(injectable) |
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self._subjects.add(injectable.subject.__name__) |
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@property |
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def injectables(self): |
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""" |
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Return all ``Injectables`` that were registered to this ``Container``. |
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:return: a list of all ``Injectables``. |
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""" |
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return self._injectables |
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def get_instance(self, hint: object) -> Optional[object]: |
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""" |
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Return the instance that corresponds to the given hint if there is an |
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instance set. |
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:param hint: a type hint that describes the object. |
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:return: an instance for that hint or None. |
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""" |
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inst, _ = self._instances.get(hint, (None, None)) |
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return inst |
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def set_instance( |
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self, |
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hint: object, |
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instance: 'jacked.Injectable', |
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priority: int = 0): |
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""" |
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Set an instance for a type hint. If there already is an instance and |
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the given priority is lesser than or equal to the priority of the |
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existing instance, then the given instance will NOT override the |
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existing. |
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:param hint: a type hint that describes the object. |
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:param instance: an instance for that hint. |
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:param priority: the priority of the instance. |
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:return: None. |
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""" |
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_, prio_existing = self._instances.get(hint, (None, -1)) |
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if priority > prio_existing: |
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self._instances[hint] = (instance, priority) |
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DEFAULT_CONTAINER = Container() |
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ramonhagenaars /
jacked
