What causes "No more elements from ${inputDesc}" in stanfordnlp/CoreNLP?

Guard each call with iterator.hasNext() before calling next()

stanfordnlp/CoreNLP · error · java.util.NoSuchElementException

No more elements from

Error message

No more elements from ${inputDesc}

What it means

CharniakScoredParsesReaderWriter's ScoredParsesIterator.next() throws NoSuchElementException when the underlying input has no more scored parses to read. This is the standard Iterator contract: next() called past the end of the parse stream. inputDesc identifies which input file/stream was exhausted.

Solutions

Guard each call with iterator.hasNext() before calling next()
Use a for-each loop over the iterable instead of manual next() calls
Verify the input parse file is complete and not truncated

Example fix

// before
while (true) { ScoredObject<Tree> so = it.next(); ... }
// after
while (it.hasNext()) { ScoredObject<Tree> so = it.next(); ... }

Defensive patterns

Strategy: type-guard

Validate before calling

if (it == null || !it.hasNext()) { return Collections.emptyListIterator(); }

Type guard

static <T> Optional<T> nextIfPresent(Iterator<T> it) { return it != null && it.hasNext() ? Optional.of(it.next()) : Optional.empty(); }

Try / catch

try { so = it.next(); } catch (NoSuchElementException e) { log.warn("parse stream exhausted early: " + inputDesc); break; }

Prevention

Always iterate with hasNext() or for-each, never bare next() calls
Validate that parse dump files contain the expected number of entries before consuming them
Handle truncated inputs gracefully instead of assuming fixed k-best counts

When it happens

Trigger: Calling next() on the returned iterator after hasNext() returned false, or calling next() without checking hasNext() while iterating a Charniak parse dump file that has fewer entries than expected.

Common situations: Assuming a k-best parse file always contains k parses per sentence; iterating with next() instead of a hasNext() guard; a truncated or corrupt parse dump ending earlier than the driver loop expects.

Understand the failure class

Background: EmptyResultError / "no results found": when an API or scraper succeeds but returns zero rows — this error's family across 9 libraries.

Related errors

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/ad3f8a0a732ec63f. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/parser/charniak/CharniakScoredParsesReaderWriter.java:253

    public List<ScoredObject<Tree>> next() {
      if (!done) {
        List<ScoredObject<Tree>> cur = next;
        next = getNext();
        processed++;
        if (next == null) {
          logger.info("Read " + processed + " trees, from "
                  + inputDesc + " in " + timing.toSecondsString() + " secs");
          done = true;
          if (closeBufferNeeded) {
            try { br.close();
            } catch (IOException ex) {
              logger.warn(ex);
            }
          }
        }
        return cur;
      } else {
        throw new NoSuchElementException("No more elements from " + inputDesc);
      }
    }
  } // end static class ScoredParsesIterator

}

View on GitHub (pinned to 1b7edd19c4)