python装饰器 练习

练习一

最初代码

class bol(object):
def __init__(self, func):
self.func = func

def __call__(self):
return "<b>{}</b>".format(self.func())

class ita(object):
def __init__(self, func):
self.func = func

def __call__(self):
return "<i>{}</i>".format(self.func())

@bol
@ita
def sayhi():
return 'hi'

改进一

class sty(object):
def __init__(self, tag):
self.tag = tag

def __call__(self, f):
def wraper():
return "<{tag}>{res}</{tag}>".format(res=f(), tag=self.tag)
return wraper

@sty('b')
@sty('i')
def sayhi():
return 'hi'

改进二

class sty(object):
def __init__(self, *tags):
self.tags = tags

def __call__(self, f):
def wraper():
n = len(self.tags)
return "{0}{1}{2}".format(('<{}>'*n).format(*self.tags), f(), ('</{}>'*n).format(*reversed(self.tags)))
return wraper

@sty('b', 'i')
def sayhi():
return 'hi'

print(sayhi())

改进三

class sty(object):
def __init__(self, *tags):
self.tags = tags

def __call__(self, f):
def wraper(*args, **kwargs):
n = len(self.tags)
return "{0}{1}{2}".format(('<{}>'*n).format(*self.tags), f(*args, **kwargs), ('</{}>'*n).format(*reversed(self.tags)))
return wraper

@sty('b', 'i')
def say(word='Hi'):
return word

print(say())
print(say('Hello'))

练习二

最初代码

import threading
import time

class DecoratorClass(object):
def __init__(self):
self.thread = None

def __call__(self, func, *args, **kwargs):
def wrapped_func(*args, **kwargs):
curr_thread = threading.currentThread().getName()
self.thread = curr_thread
print('\nthread name before running func:', self.thread)
ret_val = func()
print('\nthread name after running func:', self.thread)
return ret_val

return wrapped_func

@DecoratorClass()
def decorated_with_class():
print('running decorated w class')
time.sleep(1)
return

threads = []
for i in range(5):
t = threading.Thread(target=decorated_with_class)
threads.append(t)
t.setDaemon(True)   # 守护
t.start()

改进：进程锁

import threading
import time

class DecoratorClass(object):
def __init__(self):
self.thread = None
self.lock = threading.Lock()

def __call__(self, func, *args, **kwargs):
def wrapped_func(*args, **kwargs):

self.lock.acquire()

curr_thread = threading.currentThread().getName()
self.thread = curr_thread

print('thread name before running func:', self.thread)
ret_val = func()
print('\nthread name after running func:', self.thread)

self.lock.release()
return ret_val

return wrapped_func

@DecoratorClass()
def decorated_with_class():
print('Let me sleep 1 second...')
time.sleep(1)
return

threads = []
for i in range(5):
t = threading.Thread(target=decorated_with_class)
threads.append(t)
t.start()