Total Complexity | 4 |
Total Lines | 57 |
Duplicated Lines | 0 % |
Changes | 0 |
1 | """Proxy structural software pattern. |
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2 | |||
3 | This module contains boiler-plate code to supply the Proxy structural software |
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4 | design pattern, to the client code.""" |
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5 | |||
6 | from abc import ABC |
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7 | from typing import Generic, TypeVar |
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8 | |||
9 | T = TypeVar('T') |
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10 | |||
11 | |||
12 | __all__ = ['Proxy'] |
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13 | |||
14 | |||
15 | class ProxySubjectInterface(ABC): |
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16 | """Proxy Subject interface holding the important 'request' operation. |
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17 | |||
18 | Declares common operations for both ProxySubject and |
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19 | the Proxy. As long as the client uses ProxySubject's interface, a proxy can |
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20 | be passed pass to it, instead of a real subject. |
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21 | """ |
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22 | |||
23 | |||
24 | class Proxy(ProxySubjectInterface, Generic[T]): |
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25 | """ |
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26 | The Proxy has an interface identical to the ProxySubject. |
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27 | |||
28 | Example: |
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29 | |||
30 | >>> from software_patterns import Proxy |
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31 | >>> class PlusTen(Proxy): |
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32 | ... def __call__(self, x: int): |
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33 | ... result = self._proxy_subject(x + 10) |
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34 | ... return result |
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35 | |||
36 | >>> def plus_one(x: int): |
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37 | ... return x + 1 |
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38 | >>> plus_one(2) |
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39 | 3 |
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40 | |||
41 | >>> proxy = PlusTen(plus_one) |
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42 | >>> proxy(2) |
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43 | 13 |
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44 | """ |
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45 | |||
46 | def __init__(self, runtime_proxy: T): |
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47 | self._proxy_subject = runtime_proxy |
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48 | |||
49 | def __getattr__(self, name: str): |
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50 | return getattr(self._proxy_subject, name) |
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51 | |||
52 | def __str__(self): |
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53 | return str(self._proxy_subject) |
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54 | |||
55 | def __hash__(self): |
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56 | return hash(self._proxy_subject) |
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57 |