[Zope3-Users] Modified IntId utility

[Frank Burkhardt]

Hi,

On Mon, Sep 24, 2007 at 06:53:58PM +0200, Maken Seteva wrote:
> Fellow Zopers.
> I have made a slight modification to my intid util by inheriting from IntId and overriding 
> _generateId().
> I do this to be sure that all new created objects will have an incrementing number where
> the first object created gets id 1, the next gets id 2 and so on. This way I get for "free" 
> sorting by
> oldest/newest.
> 
> 
> class MyIntIds(IntId):
>      # We need a non-volatile nextid
>      nextid = None
> 
>      def _generateId(self):
>          # In the unlikely event that the nextid already
>          # exists, we run this in a while loop to fix it.
>          while True:
>              if len(self) == 0:
>                  self.nextid = 1
>              elif self.nextid is None:
>                  self.nextid = self.refs.maxKey() + 1
>              uid = self.nextid
>              self.nextid += 1
>              if uid not in self.refs:
>                  return uid
>              # Normally we would never get here..
>              self.nextid = None
> 
> 
> What do you think about this? Is it "safe" to do this, or have i forgotten any unforseen oddities
> that might occur in the future :O

I'm using a modified IntId utility which starts IDs at 1 and counts upwards, too.
I needed some permanent link for each object which was easy to implement via IntId.
The modification was made to safe keystrokes when typing the permalink. Typing
http://server/~251 is a lot easier than http://server/~344357462 :-) .

However, I don't use those IDs for anything else - like sorting.

Regards,

Frank