public void removeAllSeries() {
        // Unregister the collection as a change listener to each series in
        // the collection.
        for (int i = 0; i < this.data.size(); i++) {
          YIntervalSeries series = (YIntervalSeries) this.data.get(i);
          series.removeChangeListener(this);
        }
        this.data.clear();
        fireDatasetChanged();