code: public static <M, I> RowFilter<M, I> and(
          RowFilter<M, I> filter0, 
          RowFilter<M, I> filter1)
      {
          if (filter0 != null && filter1 == null)
          {
              return filter0;
          }
          if (filter0 == null && filter1 != null)
          {
              return filter1;
          }
          List<RowFilter<M, I>> filters = new ArrayList<RowFilter<M, I>>();
          if (filter0 != null)
          {
              filters.add(filter0);
          }
          if (filter1 != null)
          {
              filters.add(filter1);
          }
          return RowFilter.andFilter(filters);
      }
docs: Combine the given filters, using an "and", if they are not
  <code>null</code>. If they are both <code>null</code>, then
  the resulting filter will accept all elements.
  
  @param <M> The model type
  @param <I> The index type
  
  @param filter0 The first filter
  @param filter1 The second filter
  @return The result