Validator Sample

package se.conecte.view.validators;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import se.conecte.services.IUserService;

/**
 *
 * @author Arthur Gregorio
 *
 * @category
 *
 * @since 1.0
 * @version 1.0, 05/11/2012
 */
@Scope("request")
@Component("userLoginValidator")
public class UserLoginValidator implements Validator {

    @Autowired
    private IUserService userService;

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

        final boolean isSaved = (Boolean) component.getAttributes().get("isSaved");

        if (!isSaved) {
            final String username = value.toString();

            if (userService.findByLogin(username) != null) {
                FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_ERROR,
                        "Erro!", "Nome de usuário duplicado!");
                throw new ValidatorException(message);
            }
        }
    }
}

<p:inputText id="inLogin"
             required="true"
             value="#{userController.user.login}"
             validatorMessage="Login informado é inválido">
    <f:validateRegex pattern="[a-zA-Z0-9_]{3,16}" />
    <f:validator binding="#{userLoginValidator}"/>
    <f:attribute name="isSaved" value="#{userController.user.saved}"/>
</p:inputText>