public void addWeightedDescriptors(WeightedDescriptor elem) {
   weightedDescriptors.add(elem);
   pcs.firePropertyChange("weightedDescriptors", oldList, this.weightedDescriptors);
 }
 public void addScore(Object elem) {
   score.add(elem);
   pcs.firePropertyChange("score", oldList, this.score);
 }