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From Peter Firmstone <j...@zeus.net.au>
Subject Re: Jini Spec API changes - Advise needed
Date Sun, 02 May 2010 05:47:24 GMT
Just a small clarification:

In the presence of Jini 2.1 nodes (includes River 2.1.2) a River 2.2.0 
Reggie cannot be the default group, that must be performed by a Reggie 
prior to v2.2.0.  Otherwise ClassNotFoundException and the like will be 
thrown by the earlier nodes.

The River 2.2.0 nodes don't need to utilise the existing 
ServiceRegistrar interface at all, any earlier Reggie proxy's will be 
wrapped by a Facade automatically by River, mapping the methods of 
StreamServiceRegistrar to ServiceRegistrar, this excludes Java CDC which 
won't be able to talk to earlier versions of Reggie at all, simply 
solved by having a second Reggie of v2.2.0 or later, with a cdc group or 
something similar.



Peter Firmstone wrote:
> Christopher Dolan wrote
>> The most important thing to me is that I any River 2.2.x code I write 
>> will be able talk to
>> my Jini 2.1 code.
> I've been thinking about the impact of recent changes surrounding 
> ServiceRegistrar and DiscoveryManager, it will be possible to have a 
> binary compatible migration / upgrade path from 2.1 to 2.2.
> Reggie's implementation for 2.2.x (currently experimental and subject 
> to change) will be different from earlier versions, existing Jini 
> application code will use the new implementation via a facade if 
> running directly on the Apache River 2.2.x platform.
> The impact; while Jini 2.1 nodes exist in a djinn, you will have to 
> use at least one Reggie implementation prior to Apache River 2.2.0, 
> the new nodes can utilise earlier versions of Reggie.  Application 
> code (Services and clients) Running on 2.2.x, can use new 
> StreamServiceRegistrar methods, and Apache River 2.2.x will wrap a 
> facade around any existing Jini 2.1 Reggie's, although results will 
> not be available in marshalled form, so there won't be a performance 
> advantage unless you utilise the new Apache River 2.2.x Reggie.  The 
> good news is that you can write new application code for the later 
> Reggie version, while using the former (from a 2.2.x node) and then 
> get the performance benefits when you upgrade.
> Jini 2.1 nodes won't be able to join any groups that utilise a 2.2.x 
> Reggie.
> Existing application code, migrated from Jini 2.1 will work on Apache 
> River 2.2.x and doesn't need an earlier Reggie version, as the 
> platform will provide a facade to access the new Reggie via the old 
> interface.
> Best bet; have a look at what I've done so far & raise any concerns, 
> or suggest improvements.
> I'll post a javadoc diff in my personal apache web area, time permitting.
> Cheers,
> Peter.

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