#!/usr/bin/env python

# -*- coding: utf-8 -*-

"""http://www.testingperspective.com/wiki/doku.php/collaboration/chetan/designpatternsinpython/chain-of-responsibilitypattern"""

"""http://www.dabeaz.com/coroutines/"""

import time

import os

import sys

from contextlib import contextmanager

class Handler:

def __init__(self, successor=None):

self._successor = successor

def handle(self, request):

res = self._handle(request)

if not res:

self._successor.handle(request)

def _handle(self, request):

raise NotImplementedError('Must provide implementation in subclass.')

class ConcreteHandler1(Handler):

def _handle(self, request):

if 0 < request <= 10:

print('request {} handled in handler 1'.format(request))

return True

class ConcreteHandler2(Handler):

def _handle(self, request):

if 10 < request <= 20:

print('request {} handled in handler 2'.format(request))

return True

class ConcreteHandler3(Handler):

def _handle(self, request):

if 20 < request <= 30:

print('request {} handled in handler 3'.format(request))

return True

class DefaultHandler(Handler):

def _handle(self, request):

print('end of chain, no handler for {}'.format(request))

return True

class Client:

def __init__(self):

self.handler = ConcreteHandler1(ConcreteHandler3(ConcreteHandler2(DefaultHandler())))

def delegate(self, requests):

for request in requests:

self.handler.handle(request)

def coroutine(func):

def start(*args, **kwargs):

cr = func(*args, **kwargs)

cr.next()

return cr

return start

@coroutine

def coroutine1(target):

while True:

request = yield

if 0 < request <= 10:

print('request {} handled in coroutine 1'.format(request))

else:

target.send(request)

@coroutine

def coroutine2(target):

while True:

request = yield

if 10 < request <= 20:

print('request {} handled in coroutine 2'.format(request))

else:

target.send(request)

@coroutine

def coroutine3(target):

while True:

request = yield

if 20 < request <= 30:

print('request {} handled in coroutine 3'.format(request))

else:

target.send(request)

@coroutine

def default_coroutine():

while True:

request = yield

print('end of chain, no coroutine for {}'.format(request))

class ClientCoroutine:

def __init__(self):

self.target = coroutine1(coroutine3(coroutine2(default_coroutine())))

def delegate(self, requests):

for request in requests:

self.target.send(request)

def timeit(func):

def count(*args, **kwargs):

start = time.time()

res = func(*args, **kwargs)

count._time = time.time() - start

return res

return count

@contextmanager

def suppress_stdout():

try:

stdout, sys.stdout = sys.stdout, open(os.devnull, 'w')

yield

finally:

sys.stdout = stdout

if __name__ == "__main__":

client1 = Client()

client2 = ClientCoroutine()

requests = [2, 5, 14, 22, 18, 3, 35, 27, 20]

client1.delegate(requests)

print('-'*30)

client2.delegate(requests)

requests *= 10000

client1_delegate = timeit(client1.delegate)

client2_delegate = timeit(client2.delegate)

with suppress_stdout():

client1_delegate(requests)

client2_delegate(requests)

# lets check what is faster

print(client1_delegate._time, client2_delegate._time)

### OUTPUT ###

# request 2 handled in handler 1

# request 5 handled in handler 1

# request 14 handled in handler 2

# request 22 handled in handler 3

# request 18 handled in handler 2

# request 3 handled in handler 1

# end of chain, no handler for 35

# request 27 handled in handler 3

# request 20 handled in handler 2

# ------------------------------

# request 2 handled in coroutine 1

# request 5 handled in coroutine 1

# request 14 handled in coroutine 2

# request 22 handled in coroutine 3

# request 18 handled in coroutine 2

# request 3 handled in coroutine 1

# end of chain, no coroutine for 35

# request 27 handled in coroutine 3

# request 20 handled in coroutine 2

# (0.2369999885559082, 0.16199994087219238)