Time for action – using the custom JSF validator on the client side

Let us see how we can create a custom JSF validator and use it with the PrimeFaces CSV framework, by performing the following steps:

1. Create the CreditCardValidator class to validate whether the credit card number is in the 9999 9999 9999 9999 format or not:

   import java.util.*;
   import java.util.regex.Pattern;
   import javax.faces.application.FacesMessage;
   import javax.faces.component.UIComponent;
   import javax.faces.context.FacesContext;
   import javax.faces.validator.FacesValidator;
   import javax.faces.validator.Validator;
   import javax.faces.validator.ValidatorException;
   import org.primefaces.validate.ClientValidator;
   
   @FacesValidator("creditCardValidator")
   public class CreditCardValidator implements Validator, ClientValidator
   {
       private Pattern pattern;     
       private static final String CC_PATTERN = "^\\d{4} \\d{4} \\d{4} \\d{4}$";
   
       public CreditCardValidator() {
           pattern = Pattern.compile(CC_PATTERN);
       }
   
   ...