.filter(keyType -> keyType.getDefault() != null) .filter(keyType -> !Strings.isNullOrEmpty(keyType.getDefault().getContent())) .filter(keyType -> graphElement.accept(new GraphMLElement.GraphMLElementVisitor<Boolean>() { @Override .forEach(keyType -> { if (graphElement.getProperty(keyType.getAttrName()) == null) { graphElement.setProperty(keyType.getAttrName(), typeCastValue(keyType.getDefault().getContent(), keyType.getAttrType()));