protected Validator createValidator() throws JspException 
{
        
        FacesContext context = FacesContext.getCurrentInstance();
        Validator validator = null;
        ValueExpression vb = null;
        // If "binding" is set, use it to create a validator instance.
        if (binding != null) {
            try {
                vb = context.getApplication().getExpressionFactory().createValueExpression(context.getELContext(), 
                        binding, Object.class);
                if (vb != null) {
                    validator = (Validator)vb.getValue(context.getELContext());
                    if (validator != null) {
                        return validator;
                    }
                }
            } catch (Exception e) {
                throw new JspException(e);
            }
        } 
        // If "validatorId" is set, use it to create the validator
        // instance.  If "validatorId" and "binding" are both set, store the 
        // validator instance in the value of the property represented by
        // the value binding expression.      
        if (validatorId != null) {
            try {
                String validatorIdVal = validatorId;
                if (UIComponentTag.isValueReference(validatorId)) {
                    ValueExpression idBinding = context.getApplication().
                        getExpressionFactory().createValueExpression(context.getELContext(), 
                            validatorId, Object.class);
                    validatorIdVal = (String)idBinding.getValue(context.getELContext());
                }
                validator = context.getApplication().createValidator(validatorIdVal);
                if (validator != null) { 
                    if (vb != null) {
                        vb.setValue(context.getELContext(), validator);
                    }
                }
            } catch (Exception e) {
                throw new JspException(e);
            }
        }
        return validator;
}

Create and return a new Validator to be registered on our surrounding UIComponent .

 public int doStartTag() throws JspException 
{
        
        // Locate our parent UIComponentTag
        UIComponentClassicTagBase tag =
             UIComponentClassicTagBase.getParentUIComponentClassicTagBase(pageContext);
        if (tag == null) { 
       	    //PENDING i18n
            throw new JspException("Not nested in a UIComponentTag Error for tag with handler class:"+
                    this.getClass().getName());
        }
        // Nothing to do unless this tag created a component
        if (!tag.getCreated()) {
            return (SKIP_BODY);
        }
        UIComponent component = tag.getComponentInstance();
        if (component == null) {            
            //PENDING i18n
            throw new JspException("Can't create Component from tag.");
        }
        if (!(component instanceof EditableValueHolder)) {
            // PENDING i18n
            throw new JspException("Not nested in a tag of proper type. Error for tag with handler class:"+
                    this.getClass().getName());
        }
        Validator validator = createValidator();
        if (validator == null) {
            //noinspection NonConstantStringShouldBeStringBuffer
            String validateError = null;
            if (binding != null) {
                validateError = binding;
            }
            if (validatorId != null) {
                if (validateError != null) {
                    validateError += " or " + validatorId;
                } else {
                    validateError = validatorId;
                }
            }
            // PENDING i18n
            throw new JspException("Can't create class of type:"+
                "javax.faces.validator.Validator from:"+validateError);
        }
        // Register an instance with the appropriate component
        ((EditableValueHolder)component).addValidator(validator);
        return (SKIP_BODY);
}

Create a new instance of the specified Validator class, and register it with the UIComponent instance associated with our most immediately surrounding UIComponentTag instance, if the UIComponent instance was created by this execution of the containing JSP page.

 public  void release() 
{
        this.id = null;
}

Release references to any acquired resources.

 public  void setBinding(String binding) throws JspException 
{
        if (binding != null && !UIComponentTag.isValueReference(binding)) {
            //PENDING i18n
            throw new JspException("Invalid Expression:"+binding);
        }
        this.binding = binding;
}

Set the expression that will be used to create a ValueExpression that references a backing bean property of the Validator instance to be created.

 public  void setValidatorId(String validatorId) 
{
        this.validatorId = validatorId;
}

Set the identifer of the Validator instance to be created.