code: public void render() {
  		removeMembers(getMembers());
  		// Then go over all layers, to draw styles:
  		for (Layer<?> layer : mapModel.getLayers()) {
  			if (staticLegend || layer.isShowing()) {
  				// Go over every truly visible layer:
  				if (layer instanceof VectorLayer) {
  					ClientVectorLayerInfo layerInfo = ((VectorLayer) layer).getLayerInfo();
  
  					// For vector layer; loop over the style definitions:
  					UserStyleInfo userStyle = layerInfo.getNamedStyleInfo().getUserStyle();
  					FeatureTypeStyleInfo info = userStyle.getFeatureTypeStyleList().get(0);
  					for (int i = 0; i < info.getRuleList().size(); i++) {
  						RuleInfo rule = info.getRuleList().get(i);
  						// use title if present, name if not
  						String title = (rule.getTitle() != null ? rule.getTitle() : rule.getName());
  						// fall back to style name
  						if (title == null) {
  							title = layerInfo.getNamedStyleInfo().getName();
  						}
  						addVector((VectorLayer) layer, i, title);
  					}
  				} else if (layer instanceof RasterLayer) {
  					addRaster((RasterLayer) layer);
  				}
  			}
  		}
  	}
docs: Render the legend. This triggers a complete redraw.