Question

I don’t like the way f:convertNumber display NaN ("\ufffd") and both of the infinities ("\u221e").

Is there a way to extend the out-of-the-box converter in order to inject my own display logic? Thank you.

Answer 1

To do this:

1. Create a class that extends NumberConverter.

2. Override the getAsString method by explicitly handling your special values, and deferring to super for all others. Pseudocode:

   getAsString(FacesContext ctx, UIComponent component, Object value) {
       if (value is NaN) {
           return your-own-NaN-string;
       }
   
       if (value is infinity) {
           return your-own-infinity-string;
       }
   
       return super.getAsNumber(ctx, component, value);
   }
   

3. Register the class as a converter and use it instead of f:convertNumber.