python装饰器 练习

用类作为装饰器

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()