VisValidatableTextField (source) is a text field that input can be validated, input validation is done by implementation of InputValidator. Text field can have any number of validators, if any of them return that input is invalid, field border is changed to red. Demo

Demo source:

//field creation
textField = new VisValidatableTextField(new IntegerValidator());
//validator implementation
public class IntegerValidator implements InputValidator {
	@Override
	public boolean validateInput (String input) {
		try {
			Integer.parseInt(input);
			return true;
		} catch (NumberFormatException e) {
			return false;
		}
	}
}

The following validators are located in Validators class: (since VisUI 0.6.0)

• IntegerValidator
• FloatValidator
• GreaterThanValidator (may also be used as greater or equal)
• LesserThanValidator (may also be used as lesser or equal)

One instance of validator may be shared between text fields. You can use static final fields Validators.INTEGERS and Validators.FLOATS.