code: @Override
      public void setRingSet(IRingSet ringSet) {
          if (this.ringSet != null) this.ringSet.removeListener(this);
          this.ringSet = ringSet;
          if (this.ringSet != null) this.ringSet.addListener(this);
          notifyChanged();
      }
docs: Sets the RingSet of this ChemModel.
  
  @param   ringSet         the content of this model
  
  @see      #getRingSet