JSF rendered question

Question

Is EL-parsing of children to elements with rendered="false" really supposed to be evaluated? This is causing me alot of trouble with null pointer exceptions and similar. Looking at the following example:

<p:tab title="#{userCompetenceController.getTreeName(3)}" rendered="#{!empty userCompetenceController.getTreeName(3)}">
  <xdin:competenceTable id="competenceBox3"
                        profile="#{userCompetenceController.selectedProfile}"
                        tree="#{userCompetenceController.getCompetenceTree(3)}"
                        maxHeight="500px"/>
</p:tab>

The main issue (besides performance) is that xdin:competenceTable does not support a null tree-attribute. getTreeName(int index) returns null in this case, and is followed by a call to getCompetenceTree(3) which returns null, even though its parent (p:tab) has rendered="false"

In short: xdin:competenceTable is parsed by EL even though it's parent has rendered="false". Why?

Answer 1

Take a look at the JSF lifecylce below.

Rendering is only the last phase, and rendered="false" only affects that last phase, while errors in constructing a component happen in the first.

Non-rendered components should in fact not do anything during all phases, but it looks as though your component does not conform to that part of the spec.