Question

I have a list of objects in python that I would regularly check and destroy some of them – those which haven’t been accessed lately (i.e. no method was called).

I can maintain the last time accessed and update it in every method, but is there any more elegant way to achieve this?

Answer 1

Use a decorator for the methods you want wrapped with the timestamp functionality, as @Marcelo Cantos pointed out.

Consider this example:

from datetime import datetime
import time
import functools

def t_access(method):
    @functools.wraps(method)
    def wrapper(self):
        self.timestamp = datetime.now()
        method(self)
    return wrapper

class Foo(object):
    @t_access
    def bar(self):
        print "method bar() called"

f = Foo()
f.bar()
print f.timestamp
time.sleep(5)
f.bar()
print f.timestamp

Edit: added functools.wraps as pointed out by @Peter Milley.