Question

I have a Wicket Textfield which contains an Integer value

currentValueTextField = new TextField<IntParameter>("valueText", new PropertyModel<IntParameter>(model, "value"));

I’m attaching a custom validator to this, as follows

currentValueTextField.add(new IntegerValidator());

The validator class is

class IntegerValidator extends AbstractValidator<IntParameter> {

private static final long serialVersionUID = 5899174401360212883L;

public IntegerValidator() {
}

@Override
public void onValidate(IValidatable<IntParameter> validatable) {
    ValidationError error = new ValidationError();
    if (model.getValue() == null) {
        AttributeAppender redOutline = new AttributeAppender("style", new Model<String>("border-style:solid; border-color:#f86b5c; border-width: 3px"), ";");
        currentValueTextField.add(redOutline);
        currentValueTextField.getParent().getParent().add(redOutline);
        validatable.error(error);
        }
    }
}

However if I type nothing in the textfield, my onValidate() method is not being called.

What is the recommended way to check for null values in this case?
I would also like to do range checking on the value entered.

Answer 1

Override validateOnNullValue() that is false by default.

@Override
public boolean validateOnNullValue()
{
     return true;
}

This is the description of validateOnNullValue() method:

Indicates whether or not to validate the value if it is null. It is usually desirable to skip validation if the value is null, unless we want to make sure
the value is in fact null (a rare use case). Validators that extend this and
wish to ensure the value is null should override this method and return
true.