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From Jordan Zimmerman <jor...@jordanzimmerman.com>
Subject Re: Service Discovery and notifications
Date Mon, 23 Nov 2015 01:25:55 GMT
The cacheChanged() method of ServiceCacheListener is called each time a change in registrations
is noticed. So, you can just respond to that.

> And, out of curiosity, what happens if the service B has been registered before the service
A attaches his listener?

Your listener will not get any notifications. However, the ServiceCache always has a view
of the registered instances so you can iterate over it to get the info you want.

-Jordan

> On Nov 20, 2015, at 2:58 PM, Fabrizio Cucci <fabrizio.cucci@gmail.com> wrote:
> 
> Hello everyone,
> 
> I'm currently working on a Java project that requires some service discovery and service
coordination capabilities and I was thinking about using Curator for those purposes.
> 
> One of the main feature I would need is to let one service be notified as soon as another
service becomes available. E.g. the service A starts and at a certain point it requires some
services B. Instead of repeatedly calling the getInstance method of the ServiceProvider abstraction
at regular intervals until the service B becomes available (polling-like policy), it would
be nice to get notified as soon as the services B becomes available (i.e. at least one instance
has been registered).
> 
> Is it something feasible using something like the ServiceCacheListener ?
> If yes, would it be the best way to go?
> 
> And, out of curiosity, what happens if the service B has been registered before the service
A attaches his listener? Does the service A get immediately notified because the service B
is immediately available?
> 
> Thanks in advance for your help and suggestions,
> Fabrizio


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