code: Map buildFilterParamMap(List filters) {
          if(filters == null || filters.size() == 0)
              return null;
  
          String encoded = encodeFilters(filters);
          if(encoded == null)
              return null;
          else {
              HashMap params = new HashMap();
              params.put(PARAM_KEY_FILTER, new String[]{encoded});
              return params;
          }
      }
docs: Build the filter parameter map given this list of {@link Filter} instances.  Note, the query parameters
  returned here are <b>not</b> URL encoded.  The map contains key / value pairs as (String, String[]).
  @param filters the filters
  @return a map containing the filter query parameters