code: public void cacheDescriptorValue(IAtom atom, IAtomContainer container, IDescriptorResult value) {
          if (cachedDescriptorValues == null) {
              cachedDescriptorValues = new HashMap();
              cachedDescriptorValues.put(PREVIOUS_ATOMCONTAINER, container);
          } else if (cachedDescriptorValues.get(PREVIOUS_ATOMCONTAINER) != container) {
              cachedDescriptorValues.clear();
              cachedDescriptorValues.put(PREVIOUS_ATOMCONTAINER, container);
          }
          cachedDescriptorValues.put(atom, value);
      }
docs: Caches a DescriptorValue for a given IAtom. This method may only
  be called after setNewContainer() is called.
  
  @param atom  IAtom to cache the value for
  @param value DescriptorValue for the given IAtom