public void addOutputNode(String outputNode) {
        Preconditions.expectNotBlank(outputNode, ErrorCodeEnum.INVALID_PARAMETER, "Input node should not be empty");
        outputNodes.add(outputNode);
    }
Stream node relation info, including input node name list, output node name list.
inlong-manager/manager-pojo/src/main/java/org/apache/inlong/manager/pojo/stream/StreamNodeRelation.java