code: private void initializeStorage(final HLLType type) {
          this.type = type;
          switch(type) {
              case EMPTY:
                  // nothing to be done
                  break;
              case EXPLICIT:
                  this.explicitStorage = new LongOpenHashSet();
                  break;
              case SPARSE:
                  this.sparseProbabilisticStorage = new Int2ByteOpenHashMap();
                  break;
              case FULL:
                  this.probabilisticStorage = new BitVector(regwidth, m);
                  break;
              default:
                  throw new RuntimeException("Unsupported HLL type " + type);
          }
      }
docs: Initializes storage for the specified {@link HLLType} and changes the
  instance's {@link #type}.
  
  @param type the {@link HLLType} to initialize storage for. This cannot be
  <code>null</code> and must be an instantiable type. (For instance,
  it cannot be {@link HLLType#UNDEFINED}.)