Rendering of an element depending on primefaces rating - jsf-2

Question

I started using primafaces and I came up with the following scenario. The user rates and element and if the rating is valid then a span block appears or it hides depending the case. I am based on the example here: (http://www.primefaces.org/showcase/ui/input/rating.xhtml ) with the ajax approach. Note that a rate is valid if the user clicks on any star. So here's what I've done so far:
<h:form>
<p:panelGrid>
<p:row>
<p:column>
<p:rating value="#{searchBean.dateWeight}">
<p:ajax event="rate" listener="#{searchBean.addDatetoWeights}"
update="dates" render="dates" />
<p:ajax event="cancel"
listener="#{searchBean.removeDatefromWeights}"
update="dates" />
</p:rating>
<h:panelGroup id="dates" rendered="#{searchBean.dateRated}">
<h:outputText value="test"></h:outputText>
</h:panelGroup>
</p:column>
</p:row>
</p:panelGrid>
</h:form>
segment of the bean:
boolean dateRated;
int dateWeight;
public void addDatetoWeights(){
dateRated=true;
weights.put("date",dateWeight);
System.out.println(dateRated);
}
public void removeDatefromWeights(){
dateRated=false;
if(weights.containsKey("date"))
weights.remove("date");
}

Answer 1

Let's go back to the basics: HTML and JavaScript. It's important to also know them before diving into JSF. JSF is in the context of this question merely a HTML/JS code generator.
With <p:ajax update="dates"> you're basically telling JavaScript to grab the HTML element by the given ID and then replace its contents with the new contents retrieved from server in ajax response. However, as the <h:panelGroup id="dates"> is in first place never rendered to the HTML output, JavaScript can't find the element by document.getElementById() stuff in order to replace its contents and then just ignores the instruction.
Instead, the <p:ajax update="dates"> must refer a component which is always rendered, so that JavaScript can actually find it. Only its contents can be conditionally rendered.
Here's a rewrite:
<h:panelGroup id="dates">
<h:outputText value="test" rendered="#{searchBean.dateRated}" />
</h:panelGroup>
See also:
Why do I need to nest a component with rendered="#{some}" in another component when I want to ajax-update it?