code: public void addDataPoint(String series, DataPoint dataPoint) {
          DataSet set = store.get(series);
          if (set == null) {
              set = new DataSet();
              store.put(series, set);
          }
          set.add(dataPoint);
      }
docs: Adds a new data point to a particular series.
  
  @param series    The series this data point should be added to. If it doesn't exist, it will
  be created.
  @param dataPoint Data to be added.