Not able to validate input text field rendered using ajax in jsf 2.0

Question

<h:form>
 <h:selectManyMenu id="carsList"
                   value="#{bean.carList}"
                   style="width:400px; height:100px" label="List">
                    <f:selectItems  value="#{bean.cars}" var="i"
                                    itemLabel="#{i.code}" itemValue="#{i.Name}" />
                    <f:selectItem  itemLabel="Other" itemValue="other"/>
                    <f:ajax event="change" execute="@this" render="othermodel"/>
        </h:selectManyMenu>
                    <br></br>
                    <h:panelGroup id="othermodel">
                            <h:outputText  value="Others:" style="margin-top:10px;color:red;font-weight:bold;"
                            rendered="#{bean.carList.contains('other')}" />
                            <h:inputText size="50" id="otherinput" required="true"
                            rendered="#{bean.carList.contains('other')}"/>
                            <h:message for="otherinput"></h:message>
                    </h:panelGroup>
                       <h:commandButton value="Next" action="#{bean.submitForm}"/>
    </h:form>

My bean is requestScoped and when my carList has a value other i am able to show the panelGrid but when user don't enter any value in the input field rendered using AJAX , even i specificed required=true but it's not getting validated. And value of the input text box is null in the backend code.

How can I do the validation for the input field rendered using AJAX and why my value is coming as null? I am using JSF 2.0

Answer 1

The rendered attribute is re-evaluated during the request of the form submit. Your bean is request scoped and thus recreated on every single request (also ajax requests) with all properties set to default. So the carList property will also be emptied and the rendered attribute would evalute false before the update model values phase has filled the carList . So, for JSF, the <h:inputText> is never rendered and thus it won't be processed.

Put the bean in the view scope instead. It'll live as long as you interact with the same view by (ajax) postbacks. It's the right scope for dynamic ajax based forms with a lot of conditional rendering.

See also:

• How to choose the right bean scope?

Answer 2

I tried this with @ViewScope . When I made my Spring managed service as transient I was getting null reference after deserialization. So, i tried the below method to get the Spring Service .

    @ManagedBean(name="bean")
    @ViewScoped
    public class Bean implements Serializable {


    @ManagedProperty(value="#{appService}")
    private transient AppService appService;

      // Getting AppService Object which is singleton in the application during deserialization 
     private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
              stream.defaultReadObject();
              FacesContext context = FacesContext.getCurrentInstance();
              appService = (AppService)context.getApplication()
                    .evaluateExpressionGet(context, "#{appService}", AppService.class);
                  stream.close();  // not sure i have to do this
           }
    }

This is working for me without any issues.