TextField validation message if type conversation fails?

I have a TextField with a custom validator. The property binding behind is a BigDecimal.
When I make invalid input the validator fails accordingly. But how can I exactly define that message that should be displayed if conversation fails?

class Order { private BigDecimal price; } textField.addValidator(new AbstractValidator<BigDecimal>("price is not valid")...); input: “asdasd”
result: “could not convert value to BigDecimal”. ← how can I change this error message for the validator specific?

Can you show more of your code? Looks like there is something else that produces the message.