JSF and Power Windows

My dad is visiting, and he just picked up his rental car. He proudly announced that he got a good deal on a compact car without power windows. What's wrong with power windows? Nothing, of course, until they break. Then it becomes expensive to diagnose and fix the problem. JavaServer Faces is like power windows. When stuff works, it is great. But when it fails mysteriously, it becomes expensive to figure out what went wrong. That's what just happened to me with a seemingly innocuous radio button set. I ported a program that simulates classroom clickers to JSF 2.0 and CDI. (NB. NetBeans does a great job with autocompletion in JSF pages, and CDI is supported in 6.9.) When the student answers a question from the instructor, I grab the question text from the database. I scan the question for lines starting with 1., 2., 3., etc., and if I find them, I show a set of radio buttons. (This scanning sounds weird, but the instructor sometimes dashes off a question quickly in the classroom and has no time for navigating a fancy UI for supplying the options.) When the student clicks Save, I store the student's choice and optional text input in the database. The old app dumped all server-side state into a session-scoped managed bean. I replaced the managed bean with a CDI bean and figured that I might as well be a good citizen and use request scope instead. My app broke. The text was submitted fine. The radio button choice wasn&#...

Date: June, 27 2010
Url: http://www.java.net/blog/cayhorstmann/archive/2010/06/27/jsf-and-power-windows

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