in src/main/java/org/apache/sling/distribution/journal/impl/discovery/DiscoveryService.java [146:160]
private void handleChanges(TopologyView newView, TopologyView oldView) {
if (! newView.equals(oldView)) {
String msg = format("TopologyView changed from %s to %s", oldView, newView);
TopologyViewDiff diffView = new TopologyViewDiff(oldView, newView);
if (diffView.subscribedAgentsChanged()) {
LOG.info(msg);
} else {
LOG.debug(msg);
}
TopologyChangeHandler handler = topologyChangeHandler;
if (handler != null) {
handler.changed(diffView);
}
}
}