On 5/5/06, Detlef Schulze <[EMAIL PROTECTED]> wrote:
Hi, the company I work for has a quite large application which is based on jboss/tomcat and that uses a homegrown framework for the webpart (dispatcher servlet that follows the model 2 servlet approach with velocity as templating engine for the html). The dispatcher servlet does quite a lot in terms of authentication/authorization. It now has been decided that we want to use tapestry for the webpart. Since the application is quite large, we figured out that it is simply not possible to do a "hard" migration and migrate everything to tapestry. Therefore it is my task to find out if it is feasible for us to simply add tapestry to the application and to use it for all new features/pages that will be added to the application. The first thing that should be done with tapestry is the administration part for jBPM, that will be integrated soon. I have experience with tapestry 3 (I am the only one on the team that has experience with tapestry) but I never had to work on an application that uses tapestry in addition to an old fashioned dispatcher servlet solution. Two problems come to my mind: session handling (the user definitely don't want to log in twice) and authentication/authorization (which includes LDAP authentication) which must be integrated. Once the user is logged in, the transition from the velocity pages to the tapestry part must be transparent.
I don't know all the details of your applications but our app is 90% tapestry based and we have two additional servlets. I had no difficulties making them live together. They don't share much state though, only the Spring/Hibernate stuff. The major challege for integrating with another framework, is to handle links properly. With friendly URLS, and Tapestry 4, this has become much more easier. It is probably not difficult to wire into your existing app a framework that generates tapestry links and in tapestry you can easily write a component that generates links back to your old app. This will make the transition transparent. Concerning sharing state, this shouldn't be any problem if your both app are inside the same web.xml. You can always access the lower servlet API in tapestry and directly hack into the servlet session. Spring for instance has a nice API that allows to share Spring state accross different apps. It might even be possible to access the tapestry's ASOs outside tapestry. Thanks, Henri.
