On Wednesday, February 12, 2014 11:34:34 PM UTC+2, Ned Batchelder wrote: > Not all patterns are useful. Just because it's been enshrined in the > GoF patterns book doesn't mean that it's good for Python.
Yes, i understand up to some extend usefulness of patterns. i did not read the GoF book. yet. > I don't understand why you would like a class to pretend to make new > instances, but actually lie and return the same instance over and over. > It makes them impossible to test: your unit tests all act on the same > object, there's no way to start over with a fresh object. > > If you only want one object, create just one, and use it everywhere. > > Ned Batchelder, http://nedbatchelder.com Actually it is not about singleton. Let say if i would like to make set of resources with controllable quantity and not for single class but for let say 10 or 20 classes , so i could read config file at time of program start and create them accordingly and only when needed. having unified attribute names within resource classes allows to do more more from one place, let say leaving resource recovery to background thread via proxy methods for failed resources, or scanning of objects in resource for timeouts or ticking clocks on them for delayed response. if there is no unified template - then for every particular class i have to put a list within module and count on number of objects created and then supervision and other things have to be handled separately. Though i do not defend current approach - it is a bit hack. same can be done via inheritance from base classes or with a bit more typing via static methods. Asaf -- https://mail.python.org/mailman/listinfo/python-list