public void addPre(String pre) {
        Preconditions.expectNotBlank(pre, ErrorCodeEnum.INVALID_PARAMETER, "Pre node should not be empty");
        if (preNodes == null) {
            preNodes = Sets.newHashSet();
        }
        preNodes.add(pre);
    }
Stream node, including data node name, pre node name, post node name, field list.
inlong-manager/manager-pojo/src/main/java/org/apache/inlong/manager/pojo/stream/StreamNode.java