junkaixue commented on code in PR #2607:
URL: https://github.com/apache/helix/pull/2607#discussion_r1325343901
##########
meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/util/ZkMetaClientUtil.java:
##########
@@ -358,4 +358,25 @@ public static MetaClientException.ReturnCode
translateZooKeeperCodeToMetaClientC
return MetaClientException.ReturnCode.DB_USER_ERROR;
}
}
+
+ public static String getZkParentPath(String path) {
+ if (path.equals("/")) {
+ return null;
+ }
+
+ int idx = path.lastIndexOf('/');
+ return idx == 0 ? "/" : path.substring(0, idx);
Review Comment:
if idx ==0. It means the path is /xxxx. So the parent path should be null as
well.
##########
meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/util/ZkMetaClientUtil.java:
##########
@@ -358,4 +358,25 @@ public static MetaClientException.ReturnCode
translateZooKeeperCodeToMetaClientC
return MetaClientException.ReturnCode.DB_USER_ERROR;
}
}
+
+ public static String getZkParentPath(String path) {
+ if (path.equals("/")) {
+ return null;
+ }
+
+ int idx = path.lastIndexOf('/');
+ return idx == 0 ? "/" : path.substring(0, idx);
+ }
+
+ // Splits a path into the paths for each node along the way.
+ // /a/b/c --> /a/b/c, /a/b, /a
+ public static List<String> separateIntoUniqueNodePaths(String path) {
Review Comment:
I would suggest the algorithm is like this:
List\<String\> nodePaths = new ArrayList<>();
String[] subPath = path.split("/");
StringBuilder tempPath = new StringBuilder();
for (int i = subPath.length - 1; i >= 1; i--) {
tempPath.insert(0, subPath[I]);
tempPath.insert(0, "/");
nodePaths.add(tempPath);
}
So this guarantee the list ordered by top parent path and you don't have to
search for index over and over again, which O(n^2) as n chars for paths.
##########
meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/util/ZkMetaClientUtil.java:
##########
@@ -358,4 +358,25 @@ public static MetaClientException.ReturnCode
translateZooKeeperCodeToMetaClientC
return MetaClientException.ReturnCode.DB_USER_ERROR;
}
}
+
+ public static String getZkParentPath(String path) {
+ if (path.equals("/")) {
+ return null;
+ }
+
+ int idx = path.lastIndexOf('/');
+ return idx == 0 ? "/" : path.substring(0, idx);
+ }
+
+ // Splits a path into the paths for each node along the way.
+ // /a/b/c --> /a/b/c, /a/b, /a
+ public static List<String> separateIntoUniqueNodePaths(String path) {
+ ArrayList<String> nodePaths = new ArrayList<>();
Review Comment:
Usually java put interface not concrete class as type. So it should be:
List\<String\> nodePaths = new ArrayList<>();
##########
meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/ZkMetaClient.java:
##########
@@ -115,6 +116,52 @@ public void create(String key, Object data,
MetaClientInterface.EntryMode mode)
}
}
+ @Override
+ public void recursiveCreate(String key, T data, EntryMode mode) {
+ // Function named recursiveCreate to match naming scheme, but actual work
is iterative
+ iterativeCreate(key, data, mode, -1);
+ }
+
+ @Override
+ public void recursiveCreateWithTTL(String key, T data, long ttl) {
+ iterativeCreate(key, data, EntryMode.TTL, ttl);
+ }
+
+ private void iterativeCreate(String key, T data, EntryMode mode, long ttl) {
+ List<String> nodePaths = separateIntoUniqueNodePaths(key);
+ int i = 0;
+ // Ephemeral nodes cant have children, so change mode when creating parents
+ EntryMode parentMode = (EntryMode.EPHEMERAL.equals(mode) ?
+ EntryMode.PERSISTENT : mode);
+
+ // Iterate over paths, starting with full key then attempting each
successive parent
+ // Try /a/b/c, if fails due to NoNode then try /a/b .. etc..
+ while (i < nodePaths.size()) {
+ try {
+ if (EntryMode.TTL.equals(mode)) {
+ createWithTTL(nodePaths.get(i), data, ttl);
+ } else {
+ create(nodePaths.get(i), data, i == 0 ? mode : parentMode);
+ }
+ break;
+ // NoNodeException thrown when parent path does not exist. We allow
this and re-attempt
+ // creation of these nodes below
+ } catch (MetaClientNoNodeException ignoredParentDoesntExistException) {
+ i++;
+ }
+
+ }
+
+ // Reattempt creation of children that failed due to NoNodeException
+ while (--i >= 0) {
+ if (EntryMode.TTL.equals(mode)) {
+ createWithTTL(nodePaths.get(i), data, ttl);
+ } else {
+ create(nodePaths.get(i), data, i == 0 ? mode : parentMode);
+ }
+ }
+ }
Review Comment:
This require try catch that if two threads parallel creation the children at
the same time. Also I would imagine this should be same path as previous one.
@xyuanlu could you please help @GrantPSpencer walk through the idea?
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