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in JSF we have the well-known problems that originate from the distinction between taghandlers and components, which manifest for example in the question why JSTL-tags in datatables do not work as expected.

My question is, is there an intrinsic reason why this distinction had to be made? Why cannot we have e.g. a datatable implemented as a taghandler so that every row exists as a component in the JSF-Tree?

I am just wondering why so many people have to fall into the pits created by this distinction.

BalusC
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1 Answers1

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My question is, is there an intrinsic reason why this distinction had to be made? Why cannot we have e.g. a datatable implemented as a taghandler so that every row exists as a component in the JSF-Tree?

Efficiency. Imagine that your table has 100 rows and that there are 10 column components which in turn have 2 child components. You'd bump from 30 components to 3000 components. Ugh. The server memory wouldn't be happy with it.

... which manifest for example in the question why JSTL-tags in datatables do not work as expected.

Just don't use JSTL tags if you rely on variables which are only available during view render time. Use the rendered attribute instead.

General advice for starters in JSF: do not use JSTL until you understand the distinction between view build time and view render time. Only when you understand it, you're going to highly appreciate the powers of JSTL. It will save you from among others programmatically creating components in beans.

See also:

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