stanfordnlp/CoreNLP · error · IllegalArgumentException

Not a valid ellipses style:

Error message

Not a valid ellipses style:

What it means

PTBLexer's options parser throws this IllegalArgumentException when the "ellipses" option value cannot be converted to a LexerUtils.EllipsesEnum constant via valueOf (after trimming and uppercasing). Accepted values are the enum constants such as unicode and pt3. This surfaces when configuring PTBTokenizer options through properties or the options string.

Solutions

  1. Set ellipses to a valid enum name such as unicode or pt3 (case-insensitive).
  2. Consult LexerUtils.EllipsesEnum in your CoreNLP version for the exact accepted constants.
  3. Remove the ellipses option to use the default if not needed.
  4. Validate option strings against the enums before passing them to PTBTokenizer in production code.

Example fix

// before
PTBTokenizer<CoreLabel> tok = new PTBTokenizer<>(reader, "ellipses=dots"); // throws
// after
PTBTokenizer<CoreLabel> tok = new PTBTokenizer<>(reader, "ellipses=unicode");
Defensive patterns

Strategy: validation

Validate before calling

// Pre-validate the ellipses option against the enum
static void checkEllipsesOption(String value) {
  try {
    edu.stanford.nlp.process.LexerUtils.EllipsesEnum.valueOf(value.trim().toUpperCase(java.util.Locale.ROOT));
  } catch (IllegalArgumentException e) {
    throw new IllegalArgumentException("ellipses must be one of " + java.util.Arrays.toString(edu.stanford.nlp.process.LexerUtils.EllipsesEnum.values()) + ", got: " + value);
  }
}

Try / catch

try {
  PTBTokenizer<CoreLabel> tok = new PTBTokenizer<>(reader, options);
} catch (IllegalArgumentException e) {
  logger.error("Bad tokenizer option (allowed ellipses values: e.g. unicode, pt3): {}", e.getMessage());
  throw e;
}

Prevention

When it happens

Trigger: Setting the tokenizer option ellipses=<value> (via PTBTokenizer options string or CoreNLP tokenize properties) with a value that is not a valid LexerUtils.EllipsesEnum name, e.g. ellipses=dots or ellipses=three-dots.

Common situations: CoreNLP config files with ellipses values copied from blog posts for the wrong library version; typos; confusion between the ellipses and dashes option value sets.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/7789f7cc01d12690. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/process/PTBLexer.flex:210

          } else if ("normalizeOtherBrackets".equals(key)) {
            normalizeOtherBrackets = val;
          } else if ("quotes".equals(key)) {
            try {
              quoteStyle = LexerUtils.QuotesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException iae) {
              throw new IllegalArgumentException ("Not a valid quotes style: " + value);
            }
          } else if ("splitAssimilations".equals(key)) {
            splitAssimilations = val;
          } else if ("splitHyphenated".equals(key)) {
            splitHyphenated = val;
          } else if ("splitForwardSlash".equals(key)) {
            splitForwardSlash = val;
          } else if ("ellipses".equals(key)) {
            try {
              ellipsisStyle = LexerUtils.EllipsesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException iae) {
              throw new IllegalArgumentException ("Not a valid ellipses style: " + value);
            }
          } else if ("dashes".equals(key)) {
            try {
              dashesStyle = LexerUtils.DashesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException iae) {
              throw new IllegalArgumentException ("Not a valid dashes style: " + value);
            }
          } else if ("escapeForwardSlashAsterisk".equals(key)) {
            escapeForwardSlashAsterisk = val;
          } else if ("untokenizable".equals(key)) {
            switch (value) {
              case "noneDelete":
                untokenizable = UntokenizableOptions.NONE_DELETE;
                break;
              case "firstDelete":
                untokenizable = UntokenizableOptions.FIRST_DELETE;
                break;
              case "allDelete":

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