JSF 1.2/Seam 2.2 - validator is skipped when input it empty

Question

I am trying to call validateLength in JSF (xhtml file of seam)

<f:validateLength minimum="2" maximum="512"/>

It works for values such as text length 513 and 1 (i.e. it shows a warning, but not for 0)

The input text filed for which it is being used is set to required=false (so that it can use a4j support for empty fields, I have to show a preview based on the input)

The problem that I see is that there a validator method in a helper class but it gets ignored when the length of input is 0 (ie I put nothing , it works for non-empty values).

I also have a NullableStringConverter here but what I have noticed that as soon as that converter sets the value of null of empty string, the validator gets skipped. Here is the complete snippet of in the inputText

<h:inputText id="linkNameInput" 
    value="#{someHelper.name}"
    validator="#{someHelper.validateMethod}"
    required="false">
      <f:validateLength minimum="2" maximum="512"/>
      <f:converter  converterId="NullableStringConverter" />
</h:inputText>

I would just like the ability to validate an empty string in a validator.

http://stackoverflow.com/a/8327848/617373 ? – Daniel Oct 23 '12 at 09:22 — Daniel, Oct 23 '12 at 09:22

score 1 · Answer 1 · answered Oct 23 '12 at 10:56

I would just like the ability to validate an empty string in a validator.

That's not possible in JSF 1.x. That's only possible since JSF 2.0 (in favour of JSR303 Bean Validation support).

I'm not sure why you'd like to validate the empty string in the custom validator. There you normally use the required="true" attribute for this. If the sole goal is to change the required message, then just use requiredMessage attribute.

<h:inputText ... required="true" requiredMessage="Please enter name" />

score 0 · Answer 2 · answered Dec 10 '12 at 01:46

As mentioned already, validating an empty input String in a JSF 1.2 component is not supported. However, you can check for this null/empty model value in your backing bean on form submit and add a FacesMessage that is mapped to that specific input field. This would allow integration with server-side component-specific error message display (<h:message for="componentId" />).

FacesContext.getCurrentInstance().addMessage("componentId",
                                             facesMessageForComponent);

JSF 1.2/Seam 2.2 - validator is skipped when input it empty

2 Answers2