On Thursday 25 September 2003 00:11, Berin Loritsch wrote: > http://sys-con.com/java/article.cfm?id=2201
I would say the article is "brief" at best. Since I have worked a lot with Jini, I have a rather deep understanding of what he is trying to portray, but the important message is not really coming across, IMVHO. 1. Jini "removes" the dependency tree, in that a well-behaved services/clients "uses" other services, not "depend on" them. 2. Once the Jini infrastructure is set-up, and proper implementation of ServiceID, equals() and hashCode() for the service development is done, the deployment becomes very fluid. Noone cares where things are running, typically noone have a clue. Getting it to run properly first time is hard. 3. Registering the MBeans in the Jini Lookup Service is a pretty novel idea, but IMHO it is not enough for managability. 4. The article says that Reggie must run as an Activatable object. Not 100% true. I used to run the transient Reggie, which only takes a couple of lines to create. Now, managability goes a bit further than figuring out what is running. I had a ultra-thin "kernel" in each machine, that only new how to download and start the Bootstrap service from a "known" web server. The Bootstrap service, OTOH, was a Jini capable service, that would request the Management Service from the Jini LUS, and ask that service what should be run on this particular machine, identified by IP number only. The Bootstrap would then obtain the codebase, and download the service code and shoot up all the Jini services from there. After that the Bootstrap would regularly query the Management service for versions, and upgrade the Jini services if so... Thanks to Jini's principal of serviceAdded/serviceRemoved all clients all had to handle that services comes and goes, and if shutdown, they could pick up another instance elsewhere. Also, I didn't use JMX, I have my own version from way back in -98 that I prefer, but works very similar. The Management Service had hooks to the "Agent" in each service, and could provide very good views of what was going on in the same service on different machines, comparing loads, comparing versions, and centralized upgrades. All-in-all, once in place it is marvelous, but not easy to get it up and running. God, I miss that system.... ;o( Niclas P.S. The BootStrap service was designed to "fallback" to download (from the "known" web server) and start the Management Service if it wasn't found on the network, to avoid chicken-egg... --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
