public void write(RepositoryDataOutput output) throws IOException {
   output.writeInt(startPosition);
   output.writeInt(endPosition);
   // not null UID
   assert this.fileUID != null;
   UIDObjectFactory.getDefaultFactory().writeUID(this.fileUID, output);
 }
  protected OffsetableBase(RepositoryDataInput input) throws IOException {
    startPosition = input.readInt();
    endPosition = input.readInt();

    this.fileUID = UIDObjectFactory.getDefaultFactory().readUID(input);
    // not null UID
    assert this.fileUID != null;
    this.fileRef = null;
  }