public boolean isBlankInput() {
        for (int i = 0;; ++i) {
            char chLocal = charAt(i);
            if (chLocal == EOI) {
                token = JSONToken.EOF;
                break;
            }

            if (!isWhitespace(chLocal)) {
                return false;
            }
        }

        return true;
    }
internal method, don't invoke
@param token
src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java