sbool makeNotifyingStringBufferRotate_verbose;

sclass NotifyingStringBufferRotator implements Runnable {

  NotifyingStringBuffer buf;

  IF0<Int> getMaxChars;

  bool processing; // avoid endless loop

  *(NotifyingStringBuffer *buf, IF0<Int> *getMaxChars) {}

  run {

    if (processing) ret;

    temp tempSet(this, processing := true);

    Int max = callF(getMaxChars);

    //if (makeNotifyingStringBufferRotate_verbose) System.out.println("XX " + max + " " + buf.length());

    if (max == null || buf.length() <= max) ret;

    if (makeNotifyingStringBufferRotate_verbose) print("Rotating NotifyingStringBuffer (" + buf.length() + "/" + max + ")");

    try {

      int newLength = max/2;

      int ofs = buf.length()-newLength;

      S newString = buf.substring(ofs);

      buf.setLength(0);

      buf.append("[...] ").append(newString);

    } catch (Exception e) {

      buf.setLength(0);

    }

    buf.trimToSize();

  }

}

svoid makeNotifyingStringBufferRotate(NotifyingStringBuffer buf, IF0<Int> getMaxChars) {

  if (hasElementWithClassShortNamed('NotifyingStringBufferRotator, buf.onChange)) ret;

  buf.onChange(new NotifyingStringBufferRotator(buf, getMaxChars));

}