code: public static void fill(Mapping src, Mapping dst) {
          for (Node off : src.getOfflineNodes()) {
              dst.addOfflineNode(off);
          }
          for (VM r : src.getReadyVMs()) {
              dst.addReadyVM(r);
          }
          for (Node on : src.getOnlineNodes()) {
              dst.addOnlineNode(on);
              for (VM r : src.getRunningVMs(on)) {
                  dst.addRunningVM(r, on);
              }
              for (VM s : src.getSleepingVMs(on)) {
                  dst.addSleepingVM(s, on);
              }
  
          }
      }
docs: Fill a destination mapping with all the elements
  in a source mapping
  
  @param src the mapping to copy
  @param dst the destination mapping