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From Niclas Hedhman <nic...@hedhman.org>
Subject Re: distributed containers
Date Tue, 04 Nov 2003 01:36:02 GMT
On Tuesday 04 November 2003 05:39, Hamilton Verissimo de Oliveira (Engenharia 
- SPO) wrote:

> Just a client that:
>
> 1 - Wants a service
>     (Locator through Broadcasting or specific URLs)
> 2 - Service found
>     (Download necessary byte codes and resources)
>     (Proxies or the service as it is?)
> 3 - Use service

4. Listens to service events
A truly flexible JINI system should gracefully transcend to another service if 
a service is decommissioned, crashes or is otherwise made unavailable. That 
allows one to do really nefty configurations, load balancing, seamless 
upgrades and system fault tolerance.

> Server:
>
> 1 - Publish one or more services
> 2 - Renew the lease periodicly

Renewal of Leases is no big deal, there is a LeaseManager that one instantiate 
and it will do it automatically.

The really tricky (more or less one time job) is to get the equals() and 
hashCode() methods for the ServicesProxies (and in our case those were 
derived from the same in the Service themselves).
If not, funny serviceAdded(), serviceRemoved events will be fired all the time 
when you deploy a second identical service.


> A lot of things matches the Ioc 1 protocol, so Avalon could be used easily.
> I don't trust my memory but I think Niclas worked with JINI in the past...

Correct. Even done JINI over the Internet, i.e. GUI clients connecting to a 
JINI driven back end across the net. I think JINI is one of the funniest 
technologies out there. Haven't had time to look at any version beyond 1.1 
though :o(


Niclas

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