public String segString(Directory dir) {
   StringBuffer b = new StringBuffer();
   final int numSegments = segments.size();
   for (int i = 0; i < numSegments; i++) {
     if (i > 0) b.append(" ");
     b.append(segments.info(i).segString(dir));
   }
   if (info != null) b.append(" into ").append(info.name);
   if (optimize) b.append(" [optimize]");
   return b.toString();
 }
 public OneMerge(SegmentInfos segments, boolean useCompoundFile) {
   if (0 == segments.size())
     throw new RuntimeException("segments must include at least one segment");
   this.segments = segments;
   this.useCompoundFile = useCompoundFile;
 }