manyi/apps/web/core/statemachines.py

# -*- coding: utf-8 -*-
#!/usr/bin/env python

class StateViolationError(RuntimeError):

    pass

class WithdrawState(object):

    def new_state(self, state):
        self.__class__ = state

    def confirm(self):
        raise NotImplementedError()

    def process(self):
        raise NotImplementedError()

    def revoke(self):
        raise NotImplementedError()

    def succeed(self):
        raise NotImplementedError()

    def fail(self):
        raise NotImplementedError()

class WithdrawConfirmedState(WithdrawState):

    def confirm(self):
        raise StateViolationError('system already confirmed withdraw application')

    def process(self):
        raise self.new_state(WithdrawProcessingState)

    def revoke(self):
        raise StateViolationError('the withdraw application needs to be processed first')

    def succeed(self):
        raise StateViolationError('the withdraw application needs to be processed first')

    def fail(self):
        raise StateViolationError('the withdraw application needs to be processed first')


class WithdrawProcessingState(WithdrawState):

    def confirm(self):
        raise StateViolationError('system already confirmed the withdraw application.')

    def process(self):
        raise StateViolationError('system is already processing the withdraw application')

    def revoke(self):
        self.new_state(WithdrawRevokedState)

    def succeed(self):
        self.new_state(WithdrawSucceededState)

    def fail(self):
        self.new_state(WithdrawFailedState)


class WithdrawRevokedState(WithdrawState):

    def confirm(self):
        raise StateViolationError('system already confirmed the withdraw application.')

    def process(self):
        self.new_state(WithdrawProcessingState)

    def revoke(self):
        raise StateViolationError('the withdraw application has already been revoked.')

    def succeed(self):
        self.new_state(WithdrawSucceededState)

    def fail(self):
        self.new_state(WithdrawFailedState)

class WithdrawSucceededState(WithdrawState):

    def confirm(self):
        raise StateViolationError('system already confirmed withdraw application.')

    def process(self):
        raise StateViolationError('system cannot process a succeeded withdraw application.')

    def revoke(self):
        raise StateViolationError('cannot withdraw a succeeded withdraw application.')

    def succeed(self):
        raise StateViolationError('the withdraw has already succeeded.')

    def fail(self):
        raise StateViolationError('cannot fail a succeeded withdraw application.')

class WithdrawFailedState(WithdrawState):

    def confirm(self):
        raise StateViolationError('system already confirmed withdraw application')

    def process(self):
        raise StateViolationError('system cannot process a failed withdraw application')

    def revoke(self):
        raise StateViolationError('cannot withdraw a failed withdraw application.')

    def succeed(self):
        raise StateViolationError('cannot fail a succeeded withdraw application.')

    def fail(self):
        raise StateViolationError('the withdraw has already succeeded.')

class Connection:
    def __init__(self):
        self.new_state(ClosedConnection)

    def new_state(self, newstate):
        self.__class__ = newstate

    def read(self):
        raise NotImplementedError()

    def write(self, data):
        raise NotImplementedError()

    def open(self):
        raise NotImplementedError()

    def close(self):
        raise NotImplementedError()

class ClosedConnection(Connection):
    def read(self):
        raise RuntimeError('Not open')

    def write(self, data):
        raise RuntimeError('Not open')

    def open(self):
        self.new_state(OpenConnection)

    def close(self):
        raise RuntimeError('Already closed')

class OpenConnection(Connection):
    def read(self):
        print 'reading'

    def write(self, data):
        print 'writing'

    def open(self):
        raise RuntimeError('Already open')

    def close(self):
        self.new_state(ClosedConnection)

__all__ = ["WithdrawConfirmedState", "WithdrawProcessingState", "WithdrawRevokedState",
           "WithdrawSucceededState", "WithdrawFailedState", "StateViolationError"]