Check box and Radio Button selection gets cleared on h:selectOneMenu value change - jsf

Question

I am working on a form which has two datatables. In the first datatable, I am displaying the radio buttons and checkboxes, whereas the second datatable contains
selectOneMenu(s). Value change listener has been implemented on the selectOneMenu and on value change, the subsequent fields gets populated based on the selection.
Everything works fine except that when I select the value from the dropdown, the checkbox and the radio button values are cleared.
f:ajax event="change" has been used for the change event on selectOneMenu. Looks like the whole page gets refreshed and the values are cleared.
I also tried using f:ajax by updating the id of the datatable in which the selectOneMenu is present.
<p:dataTable styleClass="borderless" id="inResultTable" var="result" value="#{RequestBean.fooFields}" rendered="#{not empty RequestBean.fooFields}">
<p:column style="width:150px;">
<f:facet name="header">
<h:outputText value=" " />
</f:facet>
<h:outputText value="#{msg[result.fldLabel]}" />
</p:column>
<p:column>
<f:facet name="header">
<h:outputText value="" />
</f:facet>
<ui:repeat value="#{RequestBean.fooFields}"
var="itm">
<h:selectOneMenu value="#{itm.indFieldValue}"
rendered="#{result.lvlid==itm.lvlid}"
style="width:250px;padding-right:150px;text-align: left;">
<f:selectItems value="#{RequestBean[itm.indField]}" />
</h:selectOneMenu>
<h:selectOneRadio value="#{itm.indFieldValue}" rendered="#{result.lvlid==itm.lvlid and result.fldType=='radio'}"
style="width:250px;padding-right:150px;text-align: left;">
<f:selectItems value="#{RequestBean[itm.indField]}" />
</h:selectOneRadio>
<h:selectManyCheckbox value="#{itm.indFieldCheckBox}" rendered="#{result.lvlid==itm.lvlid and result.fldType=='selectbox'}">
<f:selectItems value="#{RequestBean[itm.indField]}" />
</h:selectManyCheckbox>
</ui:repeat>
</p:column>
</p:dataTable>
<p:dataTable styleClass="borderless"
id="resultTable" var="result"
value="#{RequestBean.depFields}">
<h:selectOneMenu value="#{RequestBean.field4Value}"
valueChangeListener="#{RequestBean.processValueChange4}"
rendered="#{result.lvlid=='5' and result.fldType=='selectbox'}"
style="width:250px;padding-right:150px;text-align: left;">
<f:selectItem itemLabel="--Please Select--" itemValue="#{null}" />
<f:selectItems value="#{RequestBean[result.field]}" />
<f:ajax event="change" render="#form" />
</h:selectOneMenu>
...
...
</p:dataTable>
N.B: The requirement is such that the datatable with checkbox and radio buttons has to be placed at the top. IDs cannot be used for the selectOneMenu in the second table since I am
populating the selecOneMenu(s) dynamically based upon the entries in the database.
I know that this might be a simple issue but didn't have any luck with the info posted on most websites.
Any help would be appreciated.

Answer 1

Here's your <f:ajax>.
<f:ajax event="change" render="#form" />
You didn't specify the process attribute. So it defaults to #this, which means that only the current input component is processed during submit. However, you specified a render of the whole form. So the whole form will be refreshed. However, the other input components aren't been processed during submit. So their model values won't be updated, which means that during render response the initial values will be redisplayed instead of the submitted values, which are in your case apparently blank/null.
You've basically 2 options:
Process the whole form during submit.
<f:ajax process="#form" render="#form" />
Or, update only those components which really needs to be updated.
<f:ajax render="clientId1 clientId2 clientId3" />
In your particular case I think option 2 isn't viable, so option 1 is the best one. Please note that I omitted the event attribute. It defaults to change already.
Unrelated to the concrete problem, I'm not sure what you're all doing in your value change listener method, but I only want to note that most starters abuse it for the purpose of manipulating the model values and that it don't always work quite as expected (changed model values are not reflected at all). If this is true in your case, then you should actually be using <f:ajax listener> instead.
See also:
When to use valueChangeListener or f:ajax listener?

Answer 2

The main reason for the values of Check boxes & Radio buttons getting cleared after a value change listener could be that the model values are not updated.
Value change listeners are called before updating the model.
For these kind of issues, it is very important to have an understanding of the JSF lifecycle.
Please try following code in your value change listener and see.
public void valueChange(ValueChangeEvent event){
PhaseId phase = event.getPhaseId();
if (phase.equals(PhaseId.ANY_PHASE))
{
event.setPhaseId(PhaseId.UPDATE_MODEL_VALUES);
event.queue();
return;
}
if(!phase.equals(PhaseId.UPDATE_MODEL_VALUES))
{
return;
}
// Your code
}
I didn't try this code with your example. Please let me know with complete example source code if it is not working.
Thanks.