xyuanlu commented on code in PR #2623:
URL: https://github.com/apache/helix/pull/2623#discussion_r1333564449
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meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/ZkMetaClientCache.java:
##########
@@ -59,36 +60,141 @@ public ZkMetaClientCache(ZkMetaClientConfig config,
MetaClientCacheConfig cacheC
_lazyCaching = cacheConfig.getLazyCaching();
_cacheData = cacheConfig.getCacheData();
_cacheChildren = cacheConfig.getCacheChildren();
+
+ if (_cacheData) {
+ _dataCacheMap = new ConcurrentHashMap<>();
+ }
+ if (_cacheChildren) {
+ _childrenCacheTree = new TrieNode(_rootEntry,
_rootEntry.substring(1));
+ }
}
@Override
- public Stat exists(String key) {
+ public T get(final String key) {
throw new MetaClientException("Not implemented yet.");
}
@Override
- public T get(final String key) {
+ public List<T> get(List<String> keys) {
throw new MetaClientException("Not implemented yet.");
}
@Override
public List<String> getDirectChildrenKeys(final String key) {
- throw new MetaClientException("Not implemented yet.");
+ TrieNode node = getTree(key);
+ List<String> children;
+ if (node == null || !node.isChildrenCached()) {
+ try {
+ children = _cacheClient.getChildren(key);
+ populateChildrenCache(node, children);
+ return children;
+ } catch (ZkException e) {
+ throw translateZkExceptionToMetaclientException(e);
+ }
+ }
+ return new ArrayList<>(node.getChildren().keySet());
+ }
+
+ private void populateChildrenCache(TrieNode root, List<String> children) {
+ if (root == null) {
+ return;
+ }
+ for (String child : children) {
+ updateCache("/" + child, true);
+ }
+ root.setChildrenCached(true);
}
@Override
public int countDirectChildren(final String key) {
- throw new MetaClientException("Not implemented yet.");
+ TrieNode node = getTree(key);
+ if (node == null || !node.isChildrenCached()) {
+ try {
+ List<String> children = _cacheClient.getChildren(key);
+ populateChildrenCache(node, children);
+ return _cacheClient.countChildren(key);
+ } catch (ZkException e) {
+ throw translateZkExceptionToMetaclientException(e);
+ }
+ }
+ return node.getChildren().size();
}
- @Override
- public List<T> get(List<String> keys) {
- throw new MetaClientException("Not implemented yet.");
+ private void handleCacheUpdate(String path, ChildChangeListener.ChangeType
changeType) {
+ switch (changeType) {
+ case ENTRY_CREATED:
+ updateCache(path, true);
Review Comment:
If we haven't read the node before, this will populate cache, witch may not
follow our lazy initiate pattern. Maybe reconsider. (Or we could keep it as it
is for simplicity)
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