Quick tryout of state design pattern for MLD router state transition

mldstd.py

#implementation of state design pattern for MLD router state transition
#(RFC2710)
import time

class NonQuerier:
    def __init__(self, ctx):
        print "In non-querier"
        print "Start other querier timeout"
        self.ctx = ctx
        self.timeout = time.time()

    def recv_query(self, lower):
        if lower:
            print "Resetting timeout"

    def expire(self):
        '''other querier present timer expired'''
        self.transit()

    def transit(self):
        print "Transit to querier"
        self.ctx.state = Querier(self.ctx)


class Querier:
    def __init__(self, ctx):
        print "In querier"
        print "Send general query"
        self.ctx = ctx

    def recv_query(self, lower):
        if lower:
            self.transit()

    def expire(self):
        '''general query timer expire'''
        print "Resend general query"

    def transit(self):
        print "Stop send general query thread"
        print "Transit to non-querier"
        self.ctx.state = NonQuerier(self.ctx)

class MLDCtx:
    def __init__(self):
        self.state = Querier(self)


if __name__ == '__main__':
    ctx = MLDCtx()
    ctx.state.recv_query(True)
    ctx.state.recv_query(True)
    ctx.state.expire()
    ctx.state.recv_query(True)
    ctx.state.expire()