code: public void addInstance(String src,String id,String text) 
      {
          Instance inst = new Instance(src,id,text);
          ArrayList list = (ArrayList)sourceLists.get(src);
          if (list==null) {
              list = new ArrayList();
              sourceLists.put(src,list);
              sourceNames.add(src);
          }
          list.add(inst);
      }
docs: Add a single instance, with given src and id, to the datafile