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python责任链模式

news 2025/8/4 17:52:14

责任链模式是一种行为设计模式，它允许你将请求沿着处理者链进行传递，直到有一个处理者能够处理它为止。在Python中，你可以使用多线程来实现责任链模式的框架。

首先，你需要定义一个基础的处理者类，它包含处理请求的方法。然后，你可以创建多个继承自该基础类的具体处理者类，每个类都负责处理不同类型的请求。在处理请求时，每个处理者可以决定是自己处理请求还是将其传递给下一个处理者。

import threading
import queueclass Handler(threading.Thread):def __init__(self, name, successor=None):super().__init__(name=name)self.successor = successorself.queue  = queue.Queue()# self.flag = Truedef handle_request(self,request):passdef run(self):while self.flag:request = self.queue.get()self.handle_request(request)self.queue.task_done()print('finished')class ConcreteHandlerA(Handler):def __init__(self, name, successor=None):super().__init__(name=name)self.flag = Truedef handle_request(self, request):if request == 'A':print("ConcreteHandlerA handles the request: {}".format(request))elif self.successor is not None:self.successor.handle_request(request)def run(self):while self.flag:try:request = self.queue.get(timeout=0.1)except:continueself.handle_request(request)self.queue.task_done()print('A finished')class ConcreteHandlerB(Handler):def __init__(self, name, successor=None):super().__init__(name=name)self.flag = Truedef handle_request(self, request):if request == 'B':print("ConcreteHandlerB handles the request: {}".format(request))elif self.successor is not None:self.successor.handle_request(request)def run(self):while self.flag:try:request = self.queue.get(timeout=0.1)except:continueif request:self.handle_request(request)self.queue.task_done()print('B finished')class ConcreteHandlerC(Handler):def __init__(self, name, successor=None):super().__init__(name=name)self.flag = Truedef handle_request(self, request):if request == 'C':print("ConcreteHandlerC handles the request: {}".format(request))elif self.successor is not None:self.successor.handle_request(request)def run(self):while self.flag:try:request = self.queue.get(timeout=0.1)except:continueif request:self.handle_request(request)self.queue.task_done()print('C finished')# 创建处理者实例并构建处理者链
handlerA = ConcreteHandlerA(name='HandlerA')
handlerB = ConcreteHandlerB(name='HandlerB', successor=handlerA)
handlerC = ConcreteHandlerC(name='HandlerC', successor=handlerB)# 启动处理者线程
handlerA.start()
handlerB.start()
handlerC.start()# 向处理者链发送请求
handlerC.queue.put('A')
handlerC.queue.put('B')
handlerC.queue.put('C')# 等待所有请求处理完成
handlerC.flag = False
handlerB.flag = False
handlerA.flag = False