class BlockInfo extends Block implements LightWeightGSet.LinkedElement {

  boolean addStorage(DatanodeStorageInfo storage) {
    // find the last null node
    int lastNode = ensureCapacity(1);
    setStorageInfo(lastNode, storage);
    setNext(lastNode, null);
    setPrevious(lastNode, null);
    return true;
  }

  public  BlockInfo(int replication);
  public  BlockInfo(Block blk, int replication);
  protected  BlockInfo(BlockInfo from);

}