code: private int[] countXingDataEntries(final Collection<SpatialEntry> entries, final HyperBoundingBox mbr, int[] numOf) {
      for(SpatialEntry entry : entries) {
        if(entry instanceof LeafEntry) {
          numOf[0]++;
          if(SpatialUtil.intersects(mbr, entry)) {
            numOf[1]++;
          }
        }
        else {
          N node = tree.getNode(((DirectoryEntry) entry).getPageID());
          countXingDataEntries(node.getEntries(), mbr, numOf);
        }
      }
      return numOf;
    }
docs: Count all data objects under entries and whether they intersect the given
  MBR <code>mbr</code> into <code>numOf</code>.
  
  @param entries
  @param mbr
  @param numOf array of two integers, the first one is to be filled with the
  total number of data objects, the second one with the number of data
  objects intersecting <code>mbr</code>
  @return == the (probably modified) integer array <code>numOf</code>: the
  first field is the total number of data objects, the second the
  number of data objects intersecting <code>mbr</code>