|
1 |
| -"""Implementation of the state pattern""" |
| 1 | +"""Implementation of the state pattern""" |
2 | 2 |
|
3 |
| -'''http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/''' |
| 3 | +# http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/ |
4 | 4 |
|
5 | 5 |
|
6 | 6 | class State(object):
|
7 |
| - """Base state. This is to share functionality""" |
| 7 | + """Base state. This is to share functionality""" |
8 | 8 |
|
9 |
| - def scan(self): |
10 |
| - """Scan the dial to the next station""" |
11 |
| - self.pos += 1 |
12 |
| - if self.pos == len(self.stations): |
13 |
| - self.pos = 0 |
14 |
| - print("Scanning... Station is", self.stations[self.pos], self.name) |
| 9 | + def scan(self): |
| 10 | + """Scan the dial to the next station""" |
| 11 | + self.pos += 1 |
| 12 | + if self.pos == len(self.stations): |
| 13 | + self.pos = 0 |
| 14 | + print("Scanning... Station is", self.stations[self.pos], self.name) |
15 | 15 |
|
16 | 16 |
|
17 | 17 | class AmState(State):
|
18 |
| - def __init__(self, radio): |
19 |
| - self.radio = radio |
20 |
| - self.stations = ["1250", "1380", "1510"] |
21 |
| - self.pos = 0 |
22 |
| - self.name = "AM" |
| 18 | + def __init__(self, radio): |
| 19 | + self.radio = radio |
| 20 | + self.stations = ["1250", "1380", "1510"] |
| 21 | + self.pos = 0 |
| 22 | + self.name = "AM" |
23 | 23 |
|
24 |
| - def toggle_amfm(self): |
25 |
| - print("Switching to FM") |
26 |
| - self.radio.state = self.radio.fmstate |
| 24 | + def toggle_amfm(self): |
| 25 | + print("Switching to FM") |
| 26 | + self.radio.state = self.radio.fmstate |
27 | 27 |
|
28 | 28 |
|
29 | 29 | class FmState(State):
|
30 |
| - def __init__(self, radio): |
31 |
| - self.radio = radio |
32 |
| - self.stations = ["81.3", "89.1", "103.9"] |
33 |
| - self.pos = 0 |
34 |
| - self.name = "FM" |
| 30 | + def __init__(self, radio): |
| 31 | + self.radio = radio |
| 32 | + self.stations = ["81.3", "89.1", "103.9"] |
| 33 | + self.pos = 0 |
| 34 | + self.name = "FM" |
35 | 35 |
|
36 |
| - def toggle_amfm(self): |
37 |
| - print("Switching to AM") |
38 |
| - self.radio.state = self.radio.amstate |
| 36 | + def toggle_amfm(self): |
| 37 | + print("Switching to AM") |
| 38 | + self.radio.state = self.radio.amstate |
39 | 39 |
|
40 | 40 |
|
41 | 41 | class Radio(object):
|
42 |
| - """A radio. It has a scan button, and an AM/FM toggle switch.""" |
43 |
| - def __init__(self): |
44 |
| - """We have an AM state and an FM state""" |
45 |
| - self.amstate = AmState(self) |
46 |
| - self.fmstate = FmState(self) |
47 |
| - self.state = self.amstate |
| 42 | + """A radio. It has a scan button, and an AM/FM toggle switch.""" |
| 43 | + def __init__(self): |
| 44 | + """We have an AM state and an FM state""" |
| 45 | + self.amstate = AmState(self) |
| 46 | + self.fmstate = FmState(self) |
| 47 | + self.state = self.amstate |
48 | 48 |
|
49 |
| - def toggle_amfm(self): |
50 |
| - self.state.toggle_amfm() |
| 49 | + def toggle_amfm(self): |
| 50 | + self.state.toggle_amfm() |
51 | 51 |
|
52 |
| - def scan(self): |
53 |
| - self.state.scan() |
| 52 | + def scan(self): |
| 53 | + self.state.scan() |
54 | 54 |
|
55 | 55 |
|
56 | 56 | # Test our radio out
|
57 | 57 | if __name__ == '__main__':
|
58 |
| - radio = Radio() |
59 |
| - actions = [radio.scan] * 2 + [radio.toggle_amfm] + [radio.scan] * 2 |
60 |
| - actions = actions * 2 |
| 58 | + radio = Radio() |
| 59 | + actions = [radio.scan] * 2 + [radio.toggle_amfm] + [radio.scan] * 2 |
| 60 | + actions *= 2 |
61 | 61 |
|
62 |
| - for action in actions: |
| 62 | + for action in actions: |
63 | 63 | action()
|
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