@Override
 protected void addFilterImpl(Collection<String> set) {
   FilterDBTask.addFilterKeyword(FilterDBTask.TYPE_TOPIC, set);
 }
 @Override
 protected List<String> removeAndGetFilterListImpl(Collection<String> set) {
   return FilterDBTask.removeAndGetNewFilterKeywordList(FilterDBTask.TYPE_TOPIC, set);
 }
 @Override
 protected List<String> getDBDataImpl() {
   return FilterDBTask.getFilterKeywordList(FilterDBTask.TYPE_TOPIC);
 }