code: public static <S extends Storable> OpenFilter<S> getOpenFilter(Class<S> type) {
          SoftValuedCache<Object, Filter<S>> filterCache = getFilterCache(type);
          synchronized (filterCache) {
              Filter<S> filter = filterCache.get(OPEN_KEY);
              if (filter == null) {
                  filter = OpenFilter.getCanonical(type);
                  filterCache.put(OPEN_KEY, filter);
              }
              return (OpenFilter<S>) filter;
          }
      }
docs: Returns a cached filter instance that operates on the given type, which
  allows all results to pass through.
  
  @param type type of Storable that query is made against
  @return canonical Filter instance
  @see OpenFilter