JSF 2.0, messages not displayed inside a dataTable

I have a form with a dataTable which has various columns having links and outputTexts. There is one input field which is evaluated through an ajax request . A custom validator makes sure that only integers are added to the field. The form is below.

    <form>  
            <h:dataTable var="item" value="#{listItems.mo开发者_JAVA技巧del}" id="adminlistItems"> 
                //other columns having commandLinks and outputTexts
                    <h:column>
                        <f:facet name="header" >
                            <h:outputText value="Quantity"/>
                        </f:facet>                  
                        <f:ajax listener="#{listItems.AddQuantityAction}">
                            <div style="padding:5px;float:left">
                                <h:inputText label="changeQuantity" id="addquantity" value="#{item.additionalQuantity}" maxlength="4" size="3">
                                    <f:validator validatorId="integerValidator"/>
                                </h:inputText>
                                <h:outputText value="&nbsp;"/>
                                <h:commandButton value="AddQuantity"  />
                                <h:message for="addquantity"/>
                            </div>
                        </f:ajax>  
                    </h:column>
            </h:dataTable>
        </h:form>

The code for the bean is :

    @ViewScoped
    @ManagedBean
    public class ListItems implements Serializable {    
    //...
    public String AddQuantityAction(){
              //...
      boolean result = //some action
              FacesContext context=FacesContext.getCurrentInstance();
              UIComponent component=UIComponent.getCurrentComponent(context);
              String clientID=component.getClientId(context);
              if (result) {
                   FacesMessage message = new FacesMessage("Quantity added successfully");
                  FacesContext.getCurrentInstance().addMessage(clientID, message);
              } else {
                  FacesMessage message = new FacesMessage("Quantity not added.Processing error");
                  FacesContext.getCurrentInstance().addMessage(clientID, message);
              }
              return "adminListItems"; 
          }
      }

The custom validator throws a validator exception which is not displayed. And the listener also has code for messages which too are not displayed. I have read several similar questions and this sounds a common question too. But even if i am missing something obvious,i am in need of a third eye to see what i dont.

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The execute and render of <f:ajax> defaults to @this. So only the currently active component will be processed and refreshed. When you press the button, this won't send the input value nor refresh the message component.

Fix it accordingly:

<f:ajax execute="addquantity" render="addquantity_message" listener="#{listItems.AddQuantityAction}">
    ...
    <h:message id="addquantity_message" for="addquantity"/>
    ...
</f:ajax>

By the way, why don't you just use the builtin javax.faces.Integer converter instead of that validator?

<h:inputText ... converter="javax.faces.Integer">

Further, the return value of ajax listener methods should be void. It's totally ignored in any way. Also, method names should start with lowercase. See also Java naming conventions.

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Update as per the comment, that didn't seem to work out well with regard to validation. The listener is invoked 2 times because essentially 2 ajax requests are been sent, one for the input and one for the command. I suggest to move the listener method to the <h:commandButton action>.

<f:ajax execute="addquantity" render="addquantity_message">
    ...
    <h:commandButton action="#{listItems.AddQuantityAction}" />
    <h:message id="addquantity_message" for="addquantity"/>
</f:ajax>

You'll only fix the obtained client ID to be the input ID, not the button ID.