rue if this JSON number is a integral number. This method
 semantics are defined using <code>bigDecimalValue().scale()</code>. If the
 scale is zero, then it is considered integral type. This integral type
 information can be used to invoke an appropriate accessor method to
 obtain a numeric value as in the following example:

 <pre>
 <code>
 JsonNumber num = ...
 if (num.isIntegral()) {
     num.longValue();     // or other methods to get integral value
 } else {
     num.doubleValue();   // or other metho