code: @Override
  	public List<Diagnostic> validate(final List<Diagnostic> diags) {
  		if (!isValid()) {
  			List<Serializable> argList = getMessageArguments();
  			Serializable[] args = argList.toArray(new Serializable[argList.size()]);
  
  			diags.add(new DiagnosticImpl(Diagnostic.ERROR, input, getErrorMessage(), args));
  		}
  
  		return diags;
  	}
docs: Validates the input field.
  
  @param diags the list of Diagnostics to add validation errors to.
  
  @return the updated list of validation errors.