[jsr-314-open] Ajax rendering of components among compositions?

[Andy Schwartz]

Gang -

There is one obviously critical piece of information missing here that 
clearly needs to be described more explicitly within the spec/pdldocs. 
The format for the execute/render ids in the f:ajax tag matches the 
format for ids that are passed to findComponent(). That is... ids that 
do not start with the naming container separator character are treated 
as relative to the current naming container. Ids that do start with the 
separator character are treated as absolute ids - ie. are resolved 
relative to the UIViewRoot.

So, for example, let's say we have the following component tree where we 
use f:subview to introduce a naming contianer

<f:view>
<f:subview id="namingContainer">
<h:commandButton id="insideButton"/>
<h:graphicImage id="insideImage"/>
</f:subview>

<h:graphicImage id="outsideImage"/>

</f:view>

If we want to Ajax-enable the "insideButton" to target the "insideImage, 
we would use the following f:ajax tag:

<f:ajax render="insideImage"/>

If, on the other hand, we want to target the "outerImage", which is 
outside of the naming container, then we must use an "absolute id", eg:

<f:ajax render=":outsideImage"/>

(Note the leading ":" character.) This is similar to calling 
insideButtonComponent.findComponent(":outsideImage") - ie. this will 
start the search for the "outsideImage" id up at the root naming container.

The fact that the pdldocs do not describe the format for execute/render 
ids is clearly a spec bug that needs to be addressed. I will open a bug 
to track this in a moment. This behavior is defined in the actual spec 
document itself in section 10.4.1.1 under the title 'Specifying 
“execute”/”render” Identifiers'. But even that section could use some 
clarification (eg. could use an example like the one above to illustrate 
the behavior).


David Geary wrote On 5/24/2009 11:39 PM ET:
> Notice the <f:ajax> tag. I think I'm accessing the image from the 
> parent component (map.xhtml) correctly. However, when I load the page 
> I get this:
>
> <f:ajax> contains an unknown id
> 'form:j_id1186681689_16ef8569:0:j_id1186681689_16ef8513:j_id-1105909415_41ead6fe:image'

If I had to guess (haven't looked at the implementation yet), the issue 
is that we are searching for this id relative to the composite 
component's naming container. Since this particular id is not present 
under the composite component, we do not find the target component. We 
should make this error message more explicit - ie. we should include the 
id of the naming container within which we searched for the id.

>
> If I remove the f:ajax tag, load the page, and check the source, I see 
> an <img> tag:
>
> <img 
> id="form:j_id1186681689_16ef8569:0:j_id1186681689_16ef8513:j_id-1105909415_41ead6fe:image" 
> src="..."/>
>
> And that id is *exactly* what <f:ajax> says it cannot find. It's in 
> the page, but <f:ajax> cannot find it?!?
>
> My guess is that <f:ajax> is evaluating the id before the page is 
> completely constructed, and therefore, it doesn't find it, but that's 
> just a WAG on my part.

You'll need to use the ":" prefix within your render id to indicate that 
you are specifying an absolute id. If that does not work, then my guess 
is that there is an implementation bug here.

Andy