JSF Converter not called for empty String in selectOneMenu

Question

Following example:

<h:selectOneMenu value="#{bean.value}">
    <f:selectItem itemValue="#{null}" itemDisabled="#{true}" noSelectOption="#{true}" itemLabel="choose one" />
    <f:selectItem itemValue="FEMALE" itemLabel="female" />
    <f:selectItem itemValue="MALE" itemLabel="male" />
    <f:converter converterId="myConverter" />
</h:selectOneMenu>

On initial load the value of the bean is null so the please-choose-option is selected. If the user chooses nothing the browser won’t submit a value (the selected option is disabled) and JSF will set the value to an empty String. If the page is rendered again there is no according value, JSF won't render a selected-attribute and most browsers will preselect the first non-disabled-value. Bad.

I thought I could easily change this with a Converter which converts the empty String to null in getAsObject. But in this case the converter is not called.

Anybody knows why?

I know that I could change this behaviour with javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL but this leads to other problems with other fields.

I tend to use the value '-' as the 'no-selection' value. That is easily identifiable server-side, not likely to cause a conflict and it is not an empty string or null :) — Gimby
Thanks, but won’t help me :( The value '-' will also be replaced by an empty String. Problem is that the select-element is disabled so the browser won’t submit something but JSF will change the value. I’ll update my question. — lefloh
Making the field required is not an option? The setup to me seems that it is a mandatory selection. I must admit I have no experience with making items disabled, I just let the value submit and deal with the poor selection choice server side. — Gimby
Actually this field is required. But only if the user wants to proceed. My problem happens if the user goes back one page and then continues. — lefloh

lefloh lefloh · Accepted Answer · 2014-04-23T17:44:55

I solved my problem by setting the selected-attribute manually:

<f:selectItem itemValue="#{null}" itemDisabled="#{true}" noSelectOption="#{true}" itemLabel="choose one" />
  <f:passThroughAttributes value="#{bean.attributes}" />
</f:selectItem>

public Map<String, String> getAttributes() {
    Map<String, String> attributes = new HashMap<>();
        if (value == null || "".equals(value)) {
           attributes.put("selected", "selected");
        }
    }   
    return attributes;
}

JSF Converter not called for empty String in selectOneMenu

1 Answers