[GitHub] [helix] lei-xia commented on a change in pull request #1332: Fix PreFetch annotation in ZkClient and CallbackHandler

[GitBox <gi...@apache.org>]

lei-xia commented on a change in pull request #1332:
URL: https://github.com/apache/helix/pull/1332#discussion_r479586535



##########
File path: zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/annotation/PreFetchChangedData.java
##########
@@ -22,8 +22,19 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
-
+/**
+ * An annotation used to prefetch changed data for
+ * {@link org.apache.helix.zookeeper.zkclient.IZkDataListener} in ZkClient.
+ * <p>
+ * Example:
+ * <pre>
+ * {@code @PreFetch(enabled = false)}
+ *  public class MyCallback implements IZkDataListener
+ * </pre>
+ * {@code @PreFetch(enabled = false)} means data will not be prefetched in ZkClient before
+ * handling data change.
+ */

Review comment:
       Can we add more description here, such as if this is disabled, in the ZkClient's callback handleDataChange(Path, Data), you should expect the data is null.  Also, mention what is the default value if not set.




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