in core/src/main/java/org/apache/rocketmq/streams/core/topology/TopologyBuilder.java [78:89]
private void grouping(String name, String parentName) {
if (source2Group.containsKey(parentName)) {
source2Group.get(parentName).add(name);
} else {
for (String sourceName : source2Group.keySet()) {
List<String> subsequentProcessor = source2Group.get(sourceName);
if (subsequentProcessor.contains(parentName)) {
subsequentProcessor.add(name);
}
}
}
}