Restrict input in Vaadin IntegerField when typing

There is even a simpler solution. Just change the value in the ValueChangeListener:

delayField.addValueChangeListener(event -> {
        if (event.getValue() < 0) {
            integerField.setValue(0);
        } else if (event.getValue() > 600000) {
            integerField.setValue(600000);
        }
    });