Validating required on composite component with multiple inputs - jsf-2

Question

I am using a composite component that uses a dropdown and input. The required attribute is set on the dropdown but if 'Other' is selected, then the input should also be required. I guess the required field is being validated on the 'cc.attr.value', but I also need to validate 'cc.attr.otherValue'. So, I am using the postValidate to check this required value. Clicking save should validate the inputs inside the component and then call the postValidate action. However, after postValidate, it is still calling the setter in the update models phase.
<composite:interface componentType="myInputComponent">
<composite:attribute name="value" required="true" type="java.lang.String" />
<composite:attribute name="otherValue" required="true" type="java.lang.String" />
</composite:interface>
<composite:implementation>
<s:validateAll>
<s:span id="input">
<h:selectOneMenu id="selectInput" value="#{cc.attrs.value}"
required="#{cc.required}"
onchange="otherInput = #{rich:element('otherInput')}; otherInput.value = ''; if (this.options[this.selectedIndex].text == 'Other') { otherInput.style.display = ''; otherInput.required = #{cc.required}; } else { otherInput.style.display = 'none'; otherInput.required = false; }">
<f:event type="postValidate" listener="#{cc.postValidate}" />
<!-- validators here -->
</h:selectOneMenu>
<s:span id="other">
<h:inputText id="otherInput" value="#{cc.attrs.otherValue}"
size="#{cc.attrs.width}" style="#{showOther ? '' : 'display: none'}"
onkeydown="#{not cc.attrs.inplace ? 'ignoreEnter(event)' : ''}"
onkeypress="#{cc.attrs.inplace ? 'saveOnEnter(event)' : ''}">
<f:event type="postValidate" listener="#{cc.postValidate}" />
</h:inputText>
</s:span>
</s:span>
<a4j:commandButton action="#{cc.attrs.saveAction}"
value="Save"
execute="input"
render="input" />
</s:validateAll>
</composite:implementation>
Here is the UIComponent
#FacesComponent("myInputComponent")
public class MyInputComponent extends UIInput implements NamingContainer {
static final String OTHER_INPUT_ID = "otherInput";
static final String OTHER_LABEL = "Other";
public void postValidate(ComponentSystemEvent event) {
UIInput input = (UIInput) event.getComponent();
if (input != null && OTHER_INPUT_ID.equals(input.getId())) {
UIInput selectInput = (UIInput) event.getComponent().findComponent("selectInput");;
boolean useOtherValue = false;
if (selectInput != null) {
Object value = selectInput.getValue();
useOtherValue = isUseOtherValue(value);
if (useOtherValue && isRequired()) {
String otherValue = (String) input.getValue();
if (StringUtils.emptyString(otherValue)) {
setInvalid(input);
showRequiredMessage(input);
}
}
}
}
}
private void setInvalid(UIInput input) {
input.setValid(false);
FacesContext.getCurrentInstance().validationFailed();
}
}
The component being used:
<my:myInput value="#{bean.value}" otherValue="#{bean.otherValue}" />
The setter on bean.value is still called after postValidate fails.
I've tried this on a similar component with only one input, and it works as expected when required value fails. It does not go into the setter.