code: public static IntegerVector immutable(IntegerVector vector) {
          if (vector == null)
              throw new NullPointerException("Cannot create an immutable " +
                                             "null vector");
          return new IntegerVectorView(vector, true);
      }
docs: Returns an immutable view of the given {@code IntegerVector}.
  
  @param vector The {@code IntegerVector} to decorate as immutable.
  @return An immutable version of {@code vector}.