code: public Set<Map.Entry<K, V>> entrySet() { 
         HashSet s = new HashSet(mBackingMap.size());
         for (Map.Entry e : mBackingMap.entrySet()) {
             if (mFilter.accept(e))
                 s.add(e);
         }
         return s;
      }
docs: Return a filtered set of entries.
  @see Map.entryset