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  • 【编程思想】【设计模式】【行为模式Behavioral】状态模式State

    Python版

    https://github.com/faif/python-patterns/blob/master/behavioral/state.py

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-
    
    """
    Implementation of the state pattern
    
    http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/
    
    *TL;DR80
    Implements state as a derived class of the state pattern interface.
    Implements state transitions by invoking methods from the pattern's superclass.
    """
    
    from __future__ import print_function
    
    
    class State(object):
    
        """Base state. This is to share functionality"""
    
        def scan(self):
            """Scan the dial to the next station"""
            self.pos += 1
            if self.pos == len(self.stations):
                self.pos = 0
            print(u"Scanning... Station is %s %s" %
                  (self.stations[self.pos], self.name))
    
    
    class AmState(State):
    
        def __init__(self, radio):
            self.radio = radio
            self.stations = ["1250", "1380", "1510"]
            self.pos = 0
            self.name = "AM"
    
        def toggle_amfm(self):
            print(u"Switching to FM")
            self.radio.state = self.radio.fmstate
    
    
    class FmState(State):
    
        def __init__(self, radio):
            self.radio = radio
            self.stations = ["81.3", "89.1", "103.9"]
            self.pos = 0
            self.name = "FM"
    
        def toggle_amfm(self):
            print(u"Switching to AM")
            self.radio.state = self.radio.amstate
    
    
    class Radio(object):
    
        """A radio.     It has a scan button, and an AM/FM toggle switch."""
    
        def __init__(self):
            """We have an AM state and an FM state"""
            self.amstate = AmState(self)
            self.fmstate = FmState(self)
            self.state = self.amstate
    
        def toggle_amfm(self):
            self.state.toggle_amfm()
    
        def scan(self):
            self.state.scan()
    
    
    # Test our radio out
    if __name__ == '__main__':
        radio = Radio()
        actions = [radio.scan] * 2 + [radio.toggle_amfm] + [radio.scan] * 2
        actions *= 2
    
        for action in actions:
            action()
    
    ### OUTPUT ###
    # Scanning... Station is 1380 AM
    # Scanning... Station is 1510 AM
    # Switching to FM
    # Scanning... Station is 89.1 FM
    # Scanning... Station is 103.9 FM
    # Scanning... Station is 81.3 FM
    # Scanning... Station is 89.1 FM
    # Switching to AM
    # Scanning... Station is 1250 AM
    # Scanning... Station is 1380 AM
    Python转载版
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  • 原文地址:https://www.cnblogs.com/demonzk/p/9035671.html
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