Style style = findStyle(diagram, styleId);
IGaService gaService = Graphiti.getGaService();
if (style == null) { // style not found - create new style
style = gaService.createStyle(diagram, styleId);
style.setForeground(gaService.manageColor(diagram, E_CLASS_FOREGROUND));
if (USE_GRADIENT_BACKGROUND) {
gaService.setRenderingStyle(style, E_CLASS_GRADIENT);
} else {
style.setBackground(gaService.manageColor(diagram, E_CLASS_BACKGROUND));