code: @Override
      public long length()
                      throws IOException {
          int len = physical.size();
          int answer = 0;
          for (int i = 0; i < len; i++) {
              RandomAccessFile raf = (RandomAccessFile) physical.get(i);
              if (raf != null) {
                  answer += raf.length();
              }
          }
          return answer;
      }
docs: ------------------------------------------------------------------------