//convert a String to Double form, we have to take care of cases specified in spec like INF, -INF and NaN
public Object getActualValue(String content, ValidationContext context) throws InvalidDatatypeValueException {
try{
return new XDouble(content);
} catch (NumberFormatException ex){
throw new InvalidDatatypeValueException("cvc-datatype-valid.1.2.1", new Object[]{content, "double"});
}
}//getActualValue()