74 lines
2.0 KiB
Python
74 lines
2.0 KiB
Python
from abc import ABCMeta
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from copy import deepcopy
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from pypat.behavioral.memento import Originator
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class Reusable(Originator, metaclass=ABCMeta):
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"""
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An abstract reusable class.
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External Object Pool Pattern documentation: U{https://en.wikipedia.org/wiki/Object_pool_pattern}
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"""
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def __init__(self):
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"""
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Initialize a new Reusable instance.
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"""
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self.memento = self.commit()
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def reset(self):
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"""
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Reset this objects state to the state that it was created with.
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"""
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memento = self.memento
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self.rollback(deepcopy(memento))
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self.memento = memento
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class Pool(object):
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"""
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An Object Pool design pattern implementation.
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External Object Pool Pattern documentation: U{https://en.wikipedia.org/wiki/Object_pool_pattern}
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"""
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def __init__(self, reusable_class, *args, **kwargs):
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"""
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Initialize a new object pool instance.
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@param reusable_class: The reusable class this object pool is responsible for.
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@param args: args for reusable object creation.
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@param kwargs: kwargs for reusable object creation.
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"""
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self.reusables = list()
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self.reusable_class = reusable_class
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self.args = args
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self.kwargs = kwargs
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self.pool_size = 2
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self._expand(self.pool_size)
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def acquire(self):
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"""
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Acquire an object from the pool.
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@return: An object from the pool.
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"""
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try:
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reusable = self.reusables.pop()
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except IndexError:
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self._expand(self.pool_size)
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reusable = self.reusables.pop()
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return reusable
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def release(self, reusable):
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"""
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Release an object back into the pool.
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@param reusable: The object to return to the pool.
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"""
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reusable.reset()
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self.reusables.append(reusable)
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def _expand(self, size):
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for i in range(0, size):
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self.reusables.append(self.reusable_class(*self.args, **self.kwargs))
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