public long[] getIDsForClass(Transaction trans, ClassMetadata clazz) {
   final IntArrayList ids = new IntArrayList();
   clazz
       .index()
       .traverseIds(
           trans,
           new Visitor4() {
             public void visit(Object obj) {
               ids.add(((Integer) obj).intValue());
             }
           });
   return ids.asLong();
 }
 protected void readIndex(
     ObjectContainerBase stream, ClassMetadata clazz, ByteArrayBuffer reader) {
   int indexID = reader.readInt();
   if (!stream.maintainsIndices() || !(stream instanceof LocalObjectContainer)) {
     return;
   }
   if (btree(clazz) != null) {
     return;
   }
   clazz.index().read(stream, validIndexId(indexID));
   if (isOldClassIndex(indexID)) {
     new ClassIndexesToBTrees_5_5().convert((LocalObjectContainer) stream, indexID, btree(clazz));
     stream.setDirtyInSystemTransaction(clazz);
   }
 }