solr wtf?

SolrWtf.java

  /**
   * Set the duration for which commit point is to be reserved by the deletion policy.
   *
   * @param indexVersion version of the commit point to be reserved
   * @param reserveTime  time in milliseconds for which the commit point is to be reserved
   */
  public void setReserveDuration(Long indexVersion, long reserveTime) {
    long timeToSet = System.currentTimeMillis() + reserveTime;
    for(;;) {
      Long previousTime = reserves.put(indexVersion, timeToSet);

      // this is the common success case: the older time didn't exist, or
      // came before the new time.
      if (previousTime == null || previousTime <= timeToSet) break;

      // At this point, we overwrote a longer reservation, so we want to restore the older one.
      // the problem is that an even longer reservation may come in concurrently
      // and we don't want to overwrite that one too.  We simply keep retrying in a loop
      // with the maximum time value we have seen.
      timeToSet = previousTime;      
    }
  }