Github user StefanRRichter commented on a diff in the pull request: https://github.com/apache/flink/pull/3336#discussion_r101992577 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/query/netty/message/KvStateRequestSerializer.java --- @@ -484,6 +487,71 @@ public static Throwable deserializeServerFailure(ByteBuf buf) throws IOException return null; } } + + /** + * Serializes all values of the Iterable with the given serializer. + * + * @param entries Key-value pairs to serialize + * @param keySerializer Serializer for UK + * @param valueSerializer Serializer for UV + * @param <UK> Type of the keys + * @param <UV> Type of the values + * @return Serialized values or <code>null</code> if values <code>null</code> or empty + * @throws IOException On failure during serialization + */ + public static <UK, UV> byte[] serializeMap(Iterable<Map.Entry<UK, UV>> entries, TypeSerializer<UK> keySerializer, TypeSerializer<UV> valueSerializer) throws IOException { + if (entries != null) { + Iterator<Map.Entry<UK, UV>> it = entries.iterator(); + + if (it.hasNext()) { + // Serialize + DataOutputSerializer dos = new DataOutputSerializer(32); + + while (it.hasNext()) { + Map.Entry<UK, UV> entry = it.next(); + + keySerializer.serialize(entry.getKey(), dos); + valueSerializer.serialize(entry.getValue(), dos); + } + + return dos.getCopyOfBuffer(); + } else { + return null; --- End diff -- I wonder if null and and empty map should considered the same. From the other code in the class, I think we should return an empty byte[] here. Then, you could also simply use a for-each loop over the iterable to make the code shorter.
--- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. ---