kaisun2000 commented on a change in pull request #1035:
URL: https://github.com/apache/helix/pull/1035#discussion_r435051521
##########
File path:
zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
##########
@@ -1865,17 +1934,24 @@ public Object call() throws Exception {
* exist.
*/
public List<String> watchForChilds(final String path) {
+ return watchForChilds(path, false);
+ }
+
+ private List<String> watchForChilds(final String path, boolean
skipWatchingNodeNotExist) {
if (_zookeeperEventThread != null && Thread.currentThread() ==
_zookeeperEventThread) {
throw new IllegalArgumentException("Must not be done in the zookeeper
event thread.");
}
return retryUntilConnected(new Callable<List<String>>() {
@Override
public List<String> call() throws Exception {
- exists(path, true);
+ if (!skipWatchingNodeNotExist) {
Review comment:
@jiajunwang, the code is like this:
```
public List<String> call() throws Exception {
if (!skipWatchingNodeNotExist) {
exists(path, true);
}
try {
return getChildren(path, true);
} catch (ZkNoNodeException e) {
// ignore, the "exists" watch will listen for the parent node to
appear
LOG.info("watchForChilds path not existing:" + path + "
skipWatchingNodeNoteExist:" + skipWatchingNodeNotExist);
}
return null;
}
```
if skipWatchingNodeNotExist is true, they call getChildren().
- If the parent path exists, it would install child change.
- Otherwise, if parent path not exists, it would not install parent path.
Instead, it would return null as child list. This would eventually cause the
CallbackHandler's handleChildren() code path
`_manager.removeListener(_propertyKey, _listener);`. This path would remove
CallbackHandler.
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