int datasetCount = this.datasets.size();
        for (int i = 0; i < datasetCount; i++) {
            Dataset dataset = (Dataset) this.datasets.get(i);
            if (dataset != null) {
                dataset.addChangeListener(this);
            }
        }
        int rendererCount = this.renderers.size();
        for (int i = 0; i < rendererCount; i++) {
            CategoryItemRenderer renderer
                = (CategoryItemRenderer) this.renderers.get(i);
            if (renderer != null) {
                renderer.addChangeListener(this);