INTERNAL: Refactoring updateReplConnections.

src/main/java/net/spy/memcached/MemcachedConnection.java

@@ -405,41 +405,36 @@ private void updateReplConnections(List<InetSocketAddress> addrs) throws IOExcep
     List<MemcachedReplicaGroup> changeRoleGroups = new ArrayList<>();
     List<Task> taskList = new ArrayList<>(); // tasks executed after locator update
 
-    /* In replication, after SWITCHOVER or REPL_SLAVE is received from a group
-     * and switchover is performed, but before the group's znode is changed,
-     * another group's znode can be changed.
-     *
-     * In this case, there is a problem that the switchover is restored
-     * because the state of the switchover group and the znode state are different.
-     *
-     * In order to remove the abnormal phenomenon,
-     * we find out the changed groups with the comparison of previous and current znode list,
-     * and update the state of groups based on them.
-     */
-    Set<String> changedGroups = findChangedGroups(addrs, locator.getAll());
-
+    // Create new group list from the provided addresses
     Map<String, List<ArcusReplNodeAddress>> newAllGroups =
-            ArcusReplNodeAddress.makeGroupAddrsList(findAddrsOfChangedGroups(addrs, changedGroups));
+            ArcusReplNodeAddress.makeGroupAddrsList(addrs);
 
-    // remove invalidated groups in changedGroups
-    for (Map.Entry<String, List<ArcusReplNodeAddress>> entry : newAllGroups.entrySet()) {
-      if (!ArcusReplNodeAddress.validateGroup(entry)) {
-        changedGroups.remove(entry.getKey());
-      }
-    }
+    Set<String> invalidGroups = new HashSet<>();
 
+    // Get the existing groups from the locator
     Map<String, MemcachedReplicaGroup> oldAllGroups =
             ((ArcusReplKetamaNodeLocator) locator).getAllGroups();
 
-    for (String changedGroupName : changedGroups) {
-      MemcachedReplicaGroup oldGroup = oldAllGroups.get(changedGroupName);
-      List<ArcusReplNodeAddress> newGroupAddrs = newAllGroups.get(changedGroupName);
-
-      if (oldGroup == null) {
-        // Newly added group
-        for (ArcusReplNodeAddress newAddr : newGroupAddrs) {
+    for (Map.Entry<String, List<ArcusReplNodeAddress>> entry : newAllGroups.entrySet()) {
+      if (!ArcusReplNodeAddress.validateGroup(entry)) {
+        invalidGroups.add(entry.getKey());
+        continue;
+      }
+      // Handle newly added groups
+      if (!oldAllGroups.containsKey(entry.getKey())) {
+        for (ArcusReplNodeAddress newAddr : entry.getValue()) {
           attachNodes.add(attachMemcachedNode(newAddr));
         }
+      }
+    }
+
+    for (Map.Entry<String, MemcachedReplicaGroup> oldGroupEntry : oldAllGroups.entrySet()) {
+      String groupName = oldGroupEntry.getKey();
+      MemcachedReplicaGroup oldGroup = oldGroupEntry.getValue();
+      List<ArcusReplNodeAddress> newGroupAddrs = newAllGroups.get(groupName);
+
+      // If group name exists in old groups, invalid case is ignored.
+      if (invalidGroups.contains(groupName)) {
         continue;
       }