How to invoke JSF validator on keyup event?

Question

I have implemented a JSF validator based on this example.

How can I trigger it on keyup event of ?

I am using JSF 2.0 and Richfaces

Answer 1

You can attach ajax listeners to DOM events on any JSF HTML input component by <f:ajax> tag.

<h:inputText id="foo" value="#{bean.foo}">
    <f:ajax event="keyup" execute="@this" render="fooMessage" />
    <f:validator validatorId="fooValidator" />
</h:inputText>
<h:message id="fooMessage" for="foo" />

The fooValidator can be just a simple Validator implementation which you register in the faces context by @FacesValidator annotation.

@FacesValidator("fooValidator")
public class FooValidator implements Validator {

    @Override
    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
        // ...

        if (invalid) {
            throw new ValidatorException(new FacesMessage("Fail!"));
        }
    }

}

See also:

• Communication in JSF 2 - Ajax validation

In RichFaces it's not much different. There's only the <a4j:ajax> tag which is basically just <f:ajax> on steroids. But it does not really provide additional benefits in this particular case. See also Is there any difference between f:ajax and a4j:ajax?