Conditionally displaying JSF components

Question

First, I am new to Java EE, came from a strong ASP .NET development background. I have gone through the net, and I might miss this but it seems like there is no simple and s

Answer 1

Yes, use the rendered attribute.

You usually tie it to the model rather than letting the model grab the component and manipulate it.

E.g.

Note the importance of keyword based EL operators such as gt, ge, le and lt instead of >, >=, <= and < as angle brackets < and > are reserved characters in XML. See also this related Q&A: Error parsing XHTML: The content of elements must consist of well-formed character data or markup.

As to your specific use case, let's assume that the link is passing a parameter like below:

link

You can then show the form as below:

(the #{param} is an implicit EL object referring to a Map representing the request parameters)

See also:

• Java EE 6 tutorial - Expression Language
• How to show JSF components if list is not null and has size() > 0
• Why do I need to nest a component with rendered="#{some}" in another component when I want to ajax-update it?