Question

How can I repopulate my list (stationaryList) ? What’s wrong in my code ? Nothing change in my list if I select value = CDL or MEL or NEF. Thanks.

<h:form id="frmCreateNewStationary">
<ui:param name="s" value="#{myController.selected}"/>
<h:panelGrid columns="2">
    <h:outputLabel value="Type" for="idType" />
    <h:selectOneMenu id="idType" value="#{s.stationaryid.type}">
        <f:selectItem itemLabel="Select ..." noSelectionOption="true" />
        <f:selectItem itemLabel="CDL" itemValue="CDL" />
        <f:selectItem itemLabel="MEL" itemValue="MEL" />
        <f:selectItem itemLabel="NEF" itemValue="NEF" />
        <f:ajax event="change" listener="#{myController.changeStationaryCodeList}" render="idCode" execute="@this" />
    </h:selectOneMenu>
    <h:outputLabel value="Code" for="idCode" />
    <h:selectOneMenu id="idCode" value="#{s.stationaryid.code}">
        <f:selectItem itemLabel="Select ..." noSelectionOption="true" />
        <f:selectItems value="#{myController.stationaryList}" />
    </h:selectOneMenu>
</h:panelGrid>
</h:form>

Java

private List<Stationary> stationaryList = null;
public List<Stationary> getStationaryList() {
    stationaryList = getCode();
    return stationaryList;
}

public void setStationaryList(List<Stationary> stationaryList) {
    this.stationaryList = stationaryList;
}

…

public List<Stationary> getCode() {
    //"Stationary.ccc", query = "SELECT s.code FROM Stationary s"),
    EntityManager emf = facade.getEntityManager();
    Query query = emf.createNamedQuery("Stationary.ccc");
    return query.getResultList();        
}

…

public List<Stationary> getStationaryCodeItems(String type) {
    //"Stationary.code", query = "SELECT s.code FROM Stationary s WHERE s.type = :type"),
    EntityManager emf = facade.getEntityManager();
    Query query = emf.createNamedQuery("Stationary.code");
    query.setParameter("type", type);
    return query.getResultList();
}

AjaxBehaviorEvent looks like this:

public void changeStationaryCodeList(AjaxBehaviorEvent ev) {
    stationaryList.clear();
    String type = (String) ((UIInput) ev.getComponent()).getValue();
    System.out.println("Test__changeStationaryCodeList -- state == " + type);
    stationaryList = getStationaryCodeItems(type);
    //setStationaryList(stationaryList);
}

Answer 1

Your <h:selectOneMenu id="idType"> does not have a value attribute set. Bind it to a value in your backing bean as you already are doing with <h:selectOneMenu id="idCode" value="#{s.stationaryid.code}"> and you can then use that attribute in your ajax listener as the submitted value. I also have a feeling you might not be using the right scope here. Annotate your backing bean with a @ViewScoped annotation for hitch-free results in your ajax-ing

Unrelated to this, why do you have a backing bean named “s”? That’s just going to make your code painful to read.