public String
getIdentifier() throws IOException {
	return _getIdentifier("an identifier");
}
Gets the next token from a tokenizer, ensures it is an unquoted string,
and converts it to a string.
@return The next token in the stream, as a string.
@throws TextParseException The input was invalid or not an unquoted string.
@throws IOException An I/O error occurred.
src/main/java/core/org/xbill/DNS/Tokenizer.java