How to access POST parameters when validation failed - jsf

Question

I need to show the response page depending on some of the input fields. E.g. the tabid inputHidden below:
#{controllerBean.tabId}
...
<h:form id="edit">
<h:inputHidden value="#{controllerBean.tabId}" id="tabid" />
<h:inputText value="#{controllerBean.name}" id="name" />
</h:form>
But when some other input in the same form has validation error (e.g. the "name" inputText). The "controllerBean.tabId" value will not be assigned because JSF returns at validation stage.
I still need the tabId to show the page correctly and having 2 ideas in mind:
#{param['edit:tabid']}
or use binding:
#{tabId.value}
<h:inputHidden value="#{controllerBean.tabId}" id="tabid" binding="tabId" />
My question is, which of these 2 is the better or Best Practice? Or there are even better ways to do this?
update:
Note. In my specific case, the tabid is set by client javascript.
Server reply with a few items in the html.
Javascript put these items into different tabs on the page.
One of the tabs POST data to server with the current tabid in the form.
So my server need to know the tabid to show the response page with the correct tab selected.

Answer 1

You can add a lifecycle event listener to the component and pick the value from it. I'm going to recommend the preValidate listener:
<h:form id="edit">
<h:inputHidden value="#{controllerBean.tabId}" id="tabid">
<f:event type="preValidate" listener="#{controller.grabTabId}"/>
</h:inputHidden>
<h:inputText value="#{controllerBean.name}" id="name" />
</h:form>
This registers the listener to fire just before the validation phase of the request. You'll now have a listener defined in your backing bean to look like:
public void grabTabId(ComponentSystemEvent cse){
//obtain a reference to the component
HtmlInputHidden hiddenElement = (HtmlInputHidden)cse.getComponent();
//get the value from the component.
String hiddenValue = hiddenElement.getValue();
}

Answer 2

<h:form id="edit">
<h:inputHidden value="#{controllerBean.tabId}" id="tabid" />
<h:inputText value="#{controllerBean.name}" id="name" >
<p:ajax process="tabid" immediate="true" event="keyup" />
</h:inputText>
</h:form>
The above code will do is when the user put some value the value will be processed and will be set the managedBean. that what you want I think.

Answer 3

Another non-perfect way of accomplishing this is to move the validation logic to your action method. If validation fails, you just stop processing (and add an applicable FacesMessage). You just need to be aware that all model values will have been updated, and you can clear them if necessary.
Since updating model values on failed validation goes against the JSF lifecycle, I think any solution will be somewhat of a hack.