python class as decorator

關於decorator的官方描述如下：(http://docs.python.org/glossary.html)

decorator

A function returning another function, usually applied as a function transformation using the @wrapper syntax. Common examples for decorators are classmethod() and staticmethod().

The decorator syntax is merely syntactic sugar, the following two function definitions are semantically equivalent:

def f(...):    ...f = staticmethod(f)@staticmethoddef f(...):    ...

The same concept exists for classes, but is less commonly used there. See the documentation for function definitions and class definitionsfor more about decorators.

這裡僅僅示範用一個類作為decorator， 其實主要就是類要包含__call__方法，有關__call__可以參考這裡http://www.cnblogs.com/john2000/archive/2012/03/27/2418981.html

 

#encoding:utf-8"""    class as decorator"""import timeclass A:    def __init__(self, func):        print "__init__"            def __call__(self):        time.sleep(10)        print "__call__"        @Adef test():    #編譯器將把這裡解釋為 instanceA = A(test), 當我們調用test的時候實際上調用的是instanceA (*args),即instanceA.__call__(*args)

    print "test"    if __name__ =="__main__":    test()