Setting Throttle percentage in website

[Sunil Anna]

I was not sure in which forum to place this question. So placed it in general java

I am working on a website. I've a requirement that says showing a newly added feature to a specidifed number of users.
Say 50%. So, if currently total userbase is 10,000 show this new feature to 5,000 people only. I want to achieve this programmatically.
How can I do that

I'm using
Java
Spring Web-Flow
and
Weblogic

Just a basic idea would suffice. Let me know if you need anyother info

Thanks

[Sunil Anna]

Trying my luck again

[Lester Burnham]

Something like this may work:

if ((userID % 2) == 0) {
    show_special_feature();
} else {
    // don't do anything
}

[Sunil Anna]

Thanks Lester for your reply.

But what if I need to do the same for 27% or 35% users
userID certainly wouldn't work in this case.
Actually, I need to make this percentage configurable.

[Jan Hoppmann]

Take the size of the whole userbase and check if the ID of the current user is in the first 27% (or 35%, or whatever you want). So only older users would be shown the new feature, of course. You could also check if the user ID is in the last n% (where n is your desired percentage). So only newer users would be able to use it. This is a quite simple approach, of course. I'm assuming you can't set a flag in the user itself.

[Lester Burnham]

For N% you could use

if ((userID % 100) < N)

(assuming that userIDs are uniformly distributed, of course)