xyuanlu commented on code in PR #2623:
URL: https://github.com/apache/helix/pull/2623#discussion_r1340480236
##########
meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/ZkMetaClientCache.java:
##########
@@ -102,14 +102,90 @@ public List<T> get(List<String> keys) {
return dataList;
}
+ /**
+ * Get the direct children for a given key.
+ * @param key For metadata storage that has hierarchical key space (e.g.
ZK), the key would be
+ * a parent key,
+ * For metadata storage that has non-hierarchical key space
(e.g. etcd), the key would
+ * be a prefix key.
+ * @return list of direct children or null if key doesn't exist / cache is
not populated yet.
+ */
@Override
public List<String> getDirectChildrenKeys(final String key) {
- throw new MetaClientException("Not implemented yet.");
+ if (_cacheChildren) {
+ TrieNode node = getTree(key);
+ if (node == null) {
+ LOG.debug("Children not found in cache for key: {}. This could
be because the cache is still being populated.", key);
+ return null;
+ }
+ return new ArrayList<>(node.getChildren().keySet());
+ }
+ return super.getDirectChildrenKeys(key);
}
+ /**
+ * Get the number of direct children for a given key.
+ * @param key For metadata storage that has hierarchical key space (e.g.
ZK), the key would be
+ * a parent key,
+ * For metadata storage that has non-hierarchical key space
(e.g. etcd), the key would
+ * be a prefix key.
+ * @return number of direct children or 0 if key doesn't exist / has no
children / cache is not populated yet.
+ */
@Override
public int countDirectChildren(final String key) {
- throw new MetaClientException("Not implemented yet.");
+ if (_cacheChildren) {
+ TrieNode node = getTree(key);
+ if (node == null) {
+ LOG.debug("Children not found in cache for key: {}. This could
be because the cache is still being populated.", key);
+ return 0;
+ }
+ return node.getChildren().size();
+ }
+ return super.countDirectChildren(key);
+ }
+
+ private TrieNode getTree(String path) {
+ String[] pathComponents = path.split("/");
+ TrieNode currentNode = _childrenCacheTree;
+ for (int i = 1; i < pathComponents.length; i++) {
+ String component = pathComponents[i];
+ if (!currentNode.getChildren().containsKey(component)) {
+ return currentNode;
+ } else {
+ currentNode = currentNode.getChildren().get(component);
+ }
+ }
+ return currentNode;
+ }
+
+ private void updateCache(String path, boolean isCreate) {
+ if (_cacheChildren) {
+ String[] pathComponents = path.split("/");
+ TrieNode currentNode = _childrenCacheTree;
+ TrieNode previousNode = null;
Review Comment:
Same as above. AddingNoe should be a function in TrieNode.
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