rerender causes duplicate component id error

[grimholtz]

Hi,

I have a collection of collections rendered like this:

<c:forEach items="#{user.tabs}" var="tab">
 <c:forEach items="#{tab.column0}" var="panel">
 <ui:include src="panelchrome.xhtml">
 <ui:param name="id" value="#{panel.id}"/>
 </ui:include>
 </c:forEach>

 <c:forEach items="#{tab.column1}" var="panel">
 <ui:include src="panelchrome.xhtml">
 <ui:param name="id" value="#{panel.id}"/>
 </ui:include>
 </c:forEach>
</c:forEach>

panelchrome.xhtml contains:

<h:form id="form#{id}">
 ...
 <a4j:commandButton reRender="form#{id}" image="edit.gif"/>
</h:form>

Sometimes, a duplicate component id error occurs when clicking the <a4j:commandButton/>.

What am I doing wrong? Please, please help...

grimholtz

[grimholtz]

Anyone?

[shadowcreeper]

Have you trid putting a rich:panel inside the form and rendering that instead?

If you *can* get rid of c:forEach, do it. That component tends to bring in a whole mess of sporadic reRendering problems.

Can anyone point us in the direction of a good tutorial that explains these quirks? Is it just sporadic luckiness that it doesn't happen all the time or sporadic bugs in the code that it does happen sometimes?

[daniel.soneira]

Here is some background:
http://www.ilikespam.com/blog/c:foreach-vs-ui:repeat-in-facelets

[grimholtz]

"daniel.soneira" wrote:
Here is some background:
http://www.ilikespam.com/blog/c:foreach-vs-ui:repeat-in-facelets

Yes, I'm very familiar with that article.

If you *can* get rid of c:forEach, do it. That component tends to bring in a whole mess of sporadic reRendering problems.

How? I've substituted ui:repeat but that causes other problems.

Would writing a custom component be any help?

[grimholtz]

"shadowcreeper" wrote:
Have you trid putting a rich:panel inside the form and rendering that instead?

Just tried. No help. Interestingly, the duplicate component id is always on one of the forms even if I rerender the rich:panel you recommended instead.

If i remove the forms and just have one giant form for the whole page, I get a duplicate component id on another component... not the form.

[grimholtz]

More info... I still get the duplicate component id even if I remove reRender from the commandButton and set limitToList (to limit what is reRendered when the commandButton is clicked).

WTF?

[shadowcreeper]

"grimholtz" wrote:

If you *can* get rid of c:forEach, do it. That component tends to bring in a whole mess of sporadic reRendering problems.

How? I've substituted ui:repeat but that causes other problems.

Would writing a custom component be any help?

Unfortunately it is not always easy to get rid of (hence the "if" part).

If you know you will never have more than N number of tabs, you could just conditionally render them, but if N is something larger than say 5, that probably is not feasible.

Doing it in Java is probably the cleanest way to remove the need for c:forEach, but that does not seem easy either. I wish there was a simple HOWTO for creating custom components in Java... :(

PS -- Thanks Daniel, that link is much help.

-Shadow