Python实现简单状态框架的方法

本文实例讲述了Python实现简单状态框架的方法。分享给大家供大家参考。具体分析如下：

这里使用Python实现一个简单的状态框架，代码需要在python3.2环境下运行

代码如下:from time import sleep
from random import randint, shuffle
class StateMachine(object):
    ''' Usage:  Create an instance of StateMachine, use set_starting_state(state) to give it an
        initial state to work with, then call tick() on each second (or whatever your desired
        time interval might be. '''
    def set_starting_state(self, state):
        ''' The entry state for the state machine. '''
        state.enter()
        self.state = state
    def tick(self):
        ''' Calls the current state's do_work() and checks for a transition '''
        next_state = self.state.check_transitions()
        if next_state is None:
            # Stick with this state
            self.state.do_work()
        else:
            # Next state found, transition to it
            self.state.exit()
            next_state.enter()
            self.state = next_state
class BaseState(object):
    ''' Usage: Subclass BaseState and override the enter(), do_work(), and exit() methods.
            enter()    -- Setup for your state should occur here.  This likely includes adding
                          transitions or initializing member variables.
            do_work()  -- Meat and potatoes of your state.  There may be some logic here that will
                          cause a transition to trigger.
            exit()     -- Any cleanup or final actions should occur here.  This is called just
                          before transition to the next state.