JSF 2 UIRepeat. When my composite component is nested in a repeat I can access a valueExpression but not its value? - jsf

Question

I declare my repeater in a form (lets say in main.xhtml):
<!--<itemRenderer:MetaFieldRenderer item="{kueditmeta.metaFieldFirst}" >
</itemRenderer:MetaFieldRenderer>-->
<ui:repeat var="foo" value="#{kueditmeta.metaFields}" >
<itemRenderer:MetaFieldRenderer item="#{foo}" >
</itemRenderer:MetaFieldRenderer>
</ui:repeat>
My form on submit inspect my MetaFieldRenderer.xhtml composite component in the repeater, I look at an attribute: <cc:attribute name="item" /> by calling MetaFieldRenderer().getModel();
In my FacesComponent back bean I expose getModel() method:
public MetaFieldModel getModel() {
ELContext el = this.getFacesContext().getELContext();
ValueExpression valExp = this.getValueExpression("item");
Object itemValue = valExp.getValue(el);
return (MetaFieldModel) itemValue;
}
itemValue is always null when I nest MetaFieldRenderer in a UIRepeat. But if I uncomment the one outside of the repeater itemValue is not null.
Anyone knows what's going on? Is there a better way to bind from and attribute to my FacesComponent? Am I missing a necessary implementation in my component so the UIRepeat do update its children?
(I use JSF 2.0.3)

Answer 1

I expected the components to populate themselves at pretty much the same phase (or at least before Invoke application (aka: action, navigateTo...) phase). But UIRepeat at Invoke Application phase always contained only one child, the itemRenderer it would use for repeating, the data was not repeated yet (Ho it happen at render phase I guess?).
I came to understand something through those steps:
Restore View phase bring back a plain UIRepeat and its children declare in the xhtml. No UIRepeat doesn't populate anything yet, there is only the itemRenderer without any value in it at that point.
To see how its children (if composite component) are not bound to anything at that moment use the required attribute <cc:attribute required="true"... its gonna throw an error even if you gave the attribute because uirepeat doesn't pass them.
Lesson learned, don't do logic/validation on the composite component backbean, just reflect the model. Now I drive my repeater with a list of model that can validate itself and if the model contains a warn message or whatever fancy stuff I just display it in the composite component.