Python 中的责任链模式与其他设计模式的比较

class Handler:
    def __init__(self, successor=None):
        self._successor = successor

    def handle(self, request):
        handled = self._handle(request)
        if not handled:
            self._successor.handle(request)

    def _handle(self, request):
        raise NotImplementedError('Subclass must implement abstract method')

class PidancodeHandler(Handler):
    def _handle(self, request):
        if 'pidancode.com' in request:
            print('Handled by PidancodeHandler')
            return True
        return False

class PidendevHandler(Handler):
    def _handle(self, request):
        if '皮蛋编程' in request:
            print('Handled by PidendevHandler')
            return True
        return False

class DefaultHandler(Handler):
    def _handle(self, request):
        print('DefaultHandler')
        return True

pidancode_handler = PidancodeHandler()
pidendev_handler = PidendevHandler(pidancode_handler)
default_handler = DefaultHandler(pidendev_handler)

default_handler.handle('pidancode.com')
default_handler.handle('皮蛋编程')
default_handler.handle('test')