From: Rogers, Bob [mailto:[EMAIL PROTECTED]
>
>Hi - After several days of playing around with Maverick and Velocity I've made some
>progress but still have a few unanswered newbie type questions I'm hoping someone
>could take the time to answer.
Hi!
>Question 1 - In general, where and how are the getParams() and setParam() used?
>If I code�'this.getCtx().setParam("age", "55")'��in the 'perform()' method, do I have
>access to this in the 'transform', and more specifically, how do I reference it in
>VLT?
>�
>Is it referenced by�$model.getParams()��or� $model.getParams("age")��or
>$response.getParams() .... etc.� I've tried several permutations but just can't
>figure it out.
You would reference it by $age. For document views and transforms, params are simply
set into the request attributes. The VelocityViewServlet searches this collection to
evaluate expressions. You could probably access it as $request.getAttribute("age"),
but that's annoying :-)
Note that the current CVS version of Maverick (soon to be released as v2.2) splits up
the params collection into three separate collections - controller params, view
params, and transform params. This is the result of a recent thread on this list
regarding redirect views.
>Question 2 -�I've seen in�the opt-velocity friendbook example several references to
>"$!model.xxx".��What is the bang (ie '!') �for? and why is it used?
�
This is standard Velocity syntax for "quiet" evaluation. Normally, if there is an
error evaluating $foo.bar.blah (say, the foo object doesn't have a getBar() method, or
the value of getBlah() is null) then Velocity puts the "schmoo" (Velocity lingo for an
unresolved expression) as-is into the body of the document. The ! means that nothing
should be printed when the evaluation fails.
Friendbook-velocity uses this to report errors. If there is no error, we don't want
"$model.error" showing up in the html. Instead of this syntax:
#if($model.error != null)
$model.error
#end
It is much more convenient to just do:
$!model.error
Jeff Schnitzer
[EMAIL PROTECTED]
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