Rename live instance status PAUSED to FROZEN (#1819)

Since cluster freeze mode is naming as "FREEZE", live instance status should be named to "FROZEN" accordingly.
This commit renames the enum live instance status PAUSED to FROZEN. No logic change.
diff --git a/helix-core/src/main/java/org/apache/helix/api/status/ClusterManagementMode.java b/helix-core/src/main/java/org/apache/helix/api/status/ClusterManagementMode.java
index a342a8c..daf121c 100644
--- a/helix-core/src/main/java/org/apache/helix/api/status/ClusterManagementMode.java
+++ b/helix-core/src/main/java/org/apache/helix/api/status/ClusterManagementMode.java
@@ -89,7 +89,7 @@
     public LiveInstance.LiveInstanceStatus getDesiredParticipantStatus() {
         switch (mode) {
             case CLUSTER_FREEZE:
-                return LiveInstance.LiveInstanceStatus.PAUSED;
+                return LiveInstance.LiveInstanceStatus.FROZEN;
             case NORMAL:
                 return LiveInstance.LiveInstanceStatus.NORMAL;
             default:
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/ManagementModeStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/ManagementModeStage.java
index 55a320a..a281e08 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/ManagementModeStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/ManagementModeStage.java
@@ -119,7 +119,7 @@
     // 1. All live instances are frozen
     // 2. No pending participant status change message.
     return enabledLiveInstances.stream().noneMatch(
-        instance -> !LiveInstanceStatus.PAUSED.equals(liveInstanceMap.get(instance).getStatus())
+        instance -> !LiveInstanceStatus.FROZEN.equals(liveInstanceMap.get(instance).getStatus())
             || hasPendingMessage(allInstanceMessages.get(instance),
             MessageType.PARTICIPANT_STATUS_CHANGE));
   }
diff --git a/helix-core/src/main/java/org/apache/helix/manager/zk/ParticipantManager.java b/helix-core/src/main/java/org/apache/helix/manager/zk/ParticipantManager.java
index b7a0014..09d994f 100644
--- a/helix-core/src/main/java/org/apache/helix/manager/zk/ParticipantManager.java
+++ b/helix-core/src/main/java/org/apache/helix/manager/zk/ParticipantManager.java
@@ -178,7 +178,7 @@
     String status = _liveInstanceInfoProvider.getAdditionalLiveInstanceInfo()
         .getSimpleField(LiveInstance.LiveInstanceProperty.STATUS.name());
     // If frozen, no carry-over
-    return !LiveInstance.LiveInstanceStatus.PAUSED.name().equals(status);
+    return !LiveInstance.LiveInstanceStatus.FROZEN.name().equals(status);
   }
 
   private void joinCluster() {
diff --git a/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java b/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
index 4b88f74..b5f6174 100644
--- a/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
+++ b/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
@@ -1320,7 +1320,7 @@
     // Will only create live instance
     LiveInstance.LiveInstanceStatus liveInstanceStatus =
         _messagingService.getExecutor().getLiveInstanceStatus();
-    if (LiveInstance.LiveInstanceStatus.PAUSED
+    if (LiveInstance.LiveInstanceStatus.FROZEN
         .equals(liveInstanceStatus)) {
       handleNewSessionInManagementMode(sessionId, liveInstanceStatus);
       return;
@@ -1387,7 +1387,7 @@
 
   private void handleNewSessionInManagementMode(String sessionId,
       LiveInstance.LiveInstanceStatus liveInstanceStatus) throws Exception {
-    LOG.info("Skip reset because instance is in {} status", LiveInstance.LiveInstanceStatus.PAUSED);
+    LOG.info("Skip reset because instance is in {} status", LiveInstance.LiveInstanceStatus.FROZEN);
     if (!InstanceType.PARTICIPANT.equals(_instanceType)
         && !InstanceType.CONTROLLER_PARTICIPANT.equals(_instanceType)) {
       return;
diff --git a/helix-core/src/main/java/org/apache/helix/messaging/handling/HelixTaskExecutor.java b/helix-core/src/main/java/org/apache/helix/messaging/handling/HelixTaskExecutor.java
index 11badac..b981a98 100644
--- a/helix-core/src/main/java/org/apache/helix/messaging/handling/HelixTaskExecutor.java
+++ b/helix-core/src/main/java/org/apache/helix/messaging/handling/HelixTaskExecutor.java
@@ -1352,7 +1352,7 @@
     boolean success = false;
 
     switch (toStatus) {
-      case PAUSED:
+      case FROZEN:
         _freezeSessionId = sessionId;
         _liveInstanceStatus = toStatus;
         // Entering freeze mode, update live instance status.
diff --git a/helix-core/src/main/java/org/apache/helix/model/LiveInstance.java b/helix-core/src/main/java/org/apache/helix/model/LiveInstance.java
index e711fea..ba9cc00 100644
--- a/helix-core/src/main/java/org/apache/helix/model/LiveInstance.java
+++ b/helix-core/src/main/java/org/apache/helix/model/LiveInstance.java
@@ -50,7 +50,7 @@
    * Saved values for the {@link LiveInstanceProperty#STATUS} field
    */
   public enum LiveInstanceStatus {
-    PAUSED,
+    FROZEN,
     NORMAL
   }
 
diff --git a/helix-core/src/main/java/org/apache/helix/util/HelixUtil.java b/helix-core/src/main/java/org/apache/helix/util/HelixUtil.java
index c770583..75ca302 100644
--- a/helix-core/src/main/java/org/apache/helix/util/HelixUtil.java
+++ b/helix-core/src/main/java/org/apache/helix/util/HelixUtil.java
@@ -576,7 +576,7 @@
       Map<String, LiveInstance> liveInstanceMap,
       Map<String, Collection<Message>> instancesMessages) {
     // Check live instance status and participant status change message
-    return LiveInstance.LiveInstanceStatus.PAUSED.equals(liveInstanceMap.get(instance).getStatus())
+    return LiveInstance.LiveInstanceStatus.FROZEN.equals(liveInstanceMap.get(instance).getStatus())
         || (instancesMessages.getOrDefault(instance, Collections.emptyList()).stream()
         .anyMatch(Message::isParticipantStatusChangeType));
   }
diff --git a/helix-core/src/test/java/org/apache/helix/controller/stages/TestManagementModeStage.java b/helix-core/src/test/java/org/apache/helix/controller/stages/TestManagementModeStage.java
index 1be5c6b..11a0c60 100644
--- a/helix-core/src/test/java/org/apache/helix/controller/stages/TestManagementModeStage.java
+++ b/helix-core/src/test/java/org/apache/helix/controller/stages/TestManagementModeStage.java
@@ -96,7 +96,7 @@
 
     // Mark a live instance to be pause state
     LiveInstance liveInstance = liveInstances.get(0);
-    liveInstance.setStatus(LiveInstance.LiveInstanceStatus.PAUSED);
+    liveInstance.setStatus(LiveInstance.LiveInstanceStatus.FROZEN);
     PropertyKey liveInstanceKey =
         _accessor.keyBuilder().liveInstance(liveInstance.getInstanceName());
     _accessor.updateProperty(liveInstanceKey, liveInstance);
diff --git a/helix-core/src/test/java/org/apache/helix/integration/controller/TestClusterFreezeMode.java b/helix-core/src/test/java/org/apache/helix/integration/controller/TestClusterFreezeMode.java
index afaea91..09de4dc 100644
--- a/helix-core/src/test/java/org/apache/helix/integration/controller/TestClusterFreezeMode.java
+++ b/helix-core/src/test/java/org/apache/helix/integration/controller/TestClusterFreezeMode.java
@@ -172,7 +172,7 @@
     latch.countDown();
 
     // Verify live instance status and cluster status
-    verifyLiveInstanceStatus(_participants, LiveInstance.LiveInstanceStatus.PAUSED);
+    verifyLiveInstanceStatus(_participants, LiveInstance.LiveInstanceStatus.FROZEN);
 
     expectedClusterStatus = new ClusterStatus();
     expectedClusterStatus.setManagementMode(ClusterManagementMode.Type.CLUSTER_FREEZE);
@@ -204,7 +204,7 @@
 
     // The new participant/live instance should be frozen by controller
     verifyLiveInstanceStatus(new MockParticipantManager[]{newParticipant},
-        LiveInstance.LiveInstanceStatus.PAUSED);
+        LiveInstance.LiveInstanceStatus.FROZEN);
 
     newParticipant.syncStop();
   }
@@ -236,7 +236,7 @@
     Assert.assertEquals(liveInstance.getEphemeralOwner(), _participants[1].getSessionId());
     // Status is frozen because controller sends a freeze message.
     verifyLiveInstanceStatus(new MockParticipantManager[]{_participants[1]},
-        LiveInstance.LiveInstanceStatus.PAUSED);
+        LiveInstance.LiveInstanceStatus.FROZEN);
 
     // Old session current state is deleted because of current state carry-over
     Assert.assertTrue(TestHelper.verify(
diff --git a/helix-core/src/test/java/org/apache/helix/integration/paticipant/TestParticipantFreeze.java b/helix-core/src/test/java/org/apache/helix/integration/paticipant/TestParticipantFreeze.java
index 1eb760e..334ebb1 100644
--- a/helix-core/src/test/java/org/apache/helix/integration/paticipant/TestParticipantFreeze.java
+++ b/helix-core/src/test/java/org/apache/helix/integration/paticipant/TestParticipantFreeze.java
@@ -199,7 +199,7 @@
 
     // New live instance ephemeral node with FROZEN status
     Assert.assertFalse(_originSession.equals(liveInstance.getEphemeralOwner()));
-    Assert.assertEquals(liveInstance.getStatus(), LiveInstance.LiveInstanceStatus.PAUSED);
+    Assert.assertEquals(liveInstance.getStatus(), LiveInstance.LiveInstanceStatus.FROZEN);
 
     // New session path does not exist since no current state carry over for the current session.
     Assert.assertFalse(
@@ -212,7 +212,7 @@
   @Test(dependsOnMethods = "testHandleNewSessionWhenFrozen")
   public void testUnfreezeParticipant() throws Exception {
     Message unfreezeMessage = MessageUtil
-        .createStatusChangeMessage(LiveInstance.LiveInstanceStatus.PAUSED,
+        .createStatusChangeMessage(LiveInstance.LiveInstanceStatus.FROZEN,
             LiveInstance.LiveInstanceStatus.NORMAL, _manager.getInstanceName(),
             _manager.getSessionId(), _instanceName, _participants[0].getSessionId());
     List<PropertyKey> keys = Collections
@@ -275,7 +275,7 @@
   private void freezeParticipant(MockParticipantManager participant) throws Exception {
     Message freezeMessage = MessageUtil
         .createStatusChangeMessage(LiveInstance.LiveInstanceStatus.NORMAL,
-            LiveInstance.LiveInstanceStatus.PAUSED, _manager.getInstanceName(),
+            LiveInstance.LiveInstanceStatus.FROZEN, _manager.getInstanceName(),
             _manager.getSessionId(), participant.getInstanceName(), participant.getSessionId());
 
     List<PropertyKey> keys = Collections
@@ -285,7 +285,7 @@
     Assert.assertTrue(success[0]);
 
     // Live instance status is frozen in both memory and zk
-    verifyLiveInstanceStatus(participant, LiveInstance.LiveInstanceStatus.PAUSED);
+    verifyLiveInstanceStatus(participant, LiveInstance.LiveInstanceStatus.FROZEN);
     // Freeze message is correctly deleted
     Assert.assertTrue(TestHelper.verify(() -> !_gZkClient.exists(
         _keyBuilder.message(participant.getInstanceName(), freezeMessage.getId()).getPath()),
diff --git a/helix-core/src/test/java/org/apache/helix/model/TestLiveInstance.java b/helix-core/src/test/java/org/apache/helix/model/TestLiveInstance.java
index b8024bb..84d4b45 100644
--- a/helix-core/src/test/java/org/apache/helix/model/TestLiveInstance.java
+++ b/helix-core/src/test/java/org/apache/helix/model/TestLiveInstance.java
@@ -153,7 +153,7 @@
     Assert.assertNull(testLiveInstance.getRecord()
         .getSimpleField(LiveInstance.LiveInstanceProperty.STATUS.name()));
     Assert.assertEquals(testLiveInstance.getStatus(), LiveInstance.LiveInstanceStatus.NORMAL);
-    testLiveInstance.setStatus(LiveInstance.LiveInstanceStatus.PAUSED);
-    Assert.assertEquals(testLiveInstance.getStatus(), LiveInstance.LiveInstanceStatus.PAUSED);
+    testLiveInstance.setStatus(LiveInstance.LiveInstanceStatus.FROZEN);
+    Assert.assertEquals(testLiveInstance.getStatus(), LiveInstance.LiveInstanceStatus.FROZEN);
   }
 }
diff --git a/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ClusterAccessor.java b/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ClusterAccessor.java
index 552a530..cf2457c 100644
--- a/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ClusterAccessor.java
+++ b/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ClusterAccessor.java
@@ -348,7 +348,7 @@
         // Entering cluster freeze mode, check live instance freeze status and pending ST
         for (LiveInstance liveInstance : liveInstances) {
           String instanceName = liveInstance.getInstanceName();
-          if (!LiveInstance.LiveInstanceStatus.PAUSED.equals(liveInstance.getStatus())) {
+          if (!LiveInstance.LiveInstanceStatus.FROZEN.equals(liveInstance.getStatus())) {
             liveInstancesInProgress.add(instanceName);
           }
           Stat stat = baseAccessor
@@ -361,7 +361,7 @@
       } else if (ClusterManagementMode.Type.NORMAL.equals(mode.getMode())) {
         // Exiting freeze mode, check live instance unfreeze status
         for (LiveInstance liveInstance : liveInstances) {
-          if (LiveInstance.LiveInstanceStatus.PAUSED.equals(liveInstance.getStatus())) {
+          if (LiveInstance.LiveInstanceStatus.FROZEN.equals(liveInstance.getStatus())) {
             liveInstancesInProgress.add(liveInstance.getInstanceName());
           }
         }