is
Checks whether the current TEXT event contains only whitespace characters.
For IGNORABLE_WHITESPACE, this is always true.
For TEXT and CDSECT, false is returned when the current event text contains at least one non-white space character. For any other event type an exception is thrown.
Please note: non-validating parsers are not able to distinguish whitespace and ignorable whitespace, except from whitespace outside the root element. Ignorable whitespace is reported as separate event, which is exposed via nextToken only.