On Tuesday 13 January 2004 09:59, Vikas Phonsa wrote: > My three tiers are : The Swing GUI ( Presentation ), The BusinessRules and > the Database layer ( DAOs in my case ). And all these tiers are running on > the same computer ( My database of course runs on a separate server ). > > Now this particular application that I mentioned is just a scenario I took > up to see how and where Merlin would fit in, so that I can plan Merlin > based application in future. So if the mentioned application is an entirely > wrong example scenario for which Merlin was designed for, then pls point > that out.
This is a perfectly well suited scenario for Avalon usage. > And just to mention my jars placed on a web server > could be downloaded and run to any machine on my network using webstart, > but this is not a requirement. I have been experimenting with starting Merlin via Java Webstart a few months ago. The result will hopefully make its way to the standard distribution over the coming months. On top of that, Merlin is capable to launch applications via remotely located decriptor files (the block.xml), like; merlin -execute http://niclas.hedhman.org/apps/spiffy.xml And the Jars required will be downloaded from the declared repositories. (This is the latest and greatest of Merlin technology part of the 3.2 release.) > So could I think of the classes in my application as various components > that are dependent on other components ( which in turn could have their own > dependencies ) and all these would be loaded by Merlin and the required > functionality offered by GUI would be performed in the "Active Service" > lifecycle stage of the GUI component. A "component" is required to follow the Avalon Framework rules (minimum). If this is an existing application, you would need to break it down and typically repackage it. This can be very tedious, but will also force you to think more about design. We strongly recommend the SoII in packaging as well, so you would end up with MANY jar files, and that's why the repository is an indispensible tool, as you don't need to worry about which JARs are required and have them available. Merlin will handle that. > Or is this not a good example ? We are probably coming from different angles, and hopefully slowly bridging the gap in our mutual understanding of the task at hand (Help you to understand Avalon). It is probably easier to understand Avalon from a "Server Perspective" than in the client, as client as much more complex in its interwoven dependencies. Take your Business Logic layer as a starting ground. You don't NEED to do all-or-nothing for the various tiers. You will need to scrutinize which SERVICES exists and provide the implementations. Often this exercise alone is worth switching to a COP approach in the long-term. You will then need to wire stuff back together, through the block.xml, which becomes like an application descriptor. I hope this is giving some more thoughts and guidelines. Niclas --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
