From 52dc479ae3494f8c402cb62ac2b1be8366231a01 Mon Sep 17 00:00:00 2001
From: Abhishek Balaji Radhakrishnan <abhishek.rb19@gmail.com>
Date: Fri, 26 Jul 2024 00:45:07 -0700
Subject: [PATCH] Make advanceCursor private for now.

---
 .../apache/druid/collections/CircularList.java  | 17 +++++++----------
 .../druid/collections/CircularListTest.java     | 17 -----------------
 .../coordinator/duty/KillUnusedSegments.java    |  1 -
 .../duty/KillUnusedSegmentsTest.java            |  4 ++--
 4 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/processing/src/main/java/org/apache/druid/collections/CircularList.java b/processing/src/main/java/org/apache/druid/collections/CircularList.java
index 737bb3c060e2..338340062b39 100644
--- a/processing/src/main/java/org/apache/druid/collections/CircularList.java
+++ b/processing/src/main/java/org/apache/druid/collections/CircularList.java
@@ -75,17 +75,14 @@ private T peekNext()
         int nextPosition = currentPosition < collection.size() ? currentPosition : 0;
         return collection.get(nextPosition);
       }
-    };
-  }
 
-  /**
-   * Advances the cursor position in the circular list. If the position reaches the end of the list, it wraps around.
-   */
-  public void advanceCursor()
-  {
-    if (++currentPosition >= collection.size()) {
-      currentPosition = 0;
-    }
+      private void advanceCursor()
+      {
+        if (++currentPosition >= collection.size()) {
+          currentPosition = 0;
+        }
+      }
+    };
   }
 
   /**
diff --git a/processing/src/test/java/org/apache/druid/collections/CircularListTest.java b/processing/src/test/java/org/apache/druid/collections/CircularListTest.java
index 40a38be612dd..ab66aeb0bcb3 100644
--- a/processing/src/test/java/org/apache/druid/collections/CircularListTest.java
+++ b/processing/src/test/java/org/apache/druid/collections/CircularListTest.java
@@ -66,23 +66,6 @@ public void testIterateInReverseOrder()
     Assert.assertEquals(ImmutableList.of(100, 0, -1, -4, 100, 0, -1, -4), observedElements);
   }
 
-  @Test
-  public void testAdvanceCursor()
-  {
-    final Set<Integer> input = ImmutableSet.of(1, 10, 35, 50);
-    final CircularList<Integer> circularList = new CircularList<>(input, Comparator.naturalOrder());
-    final Iterator<Integer> iterator = circularList.iterator();
-
-    circularList.advanceCursor();
-    Assert.assertTrue(iterator.hasNext());
-    Assert.assertEquals((Integer) 10, iterator.next());
-
-    circularList.advanceCursor();
-    circularList.advanceCursor();
-    Assert.assertTrue(iterator.hasNext());
-    Assert.assertEquals((Integer) 1, iterator.next());
-  }
-
   @Test
   public void testEqualsSet()
   {
diff --git a/server/src/main/java/org/apache/druid/server/coordinator/duty/KillUnusedSegments.java b/server/src/main/java/org/apache/druid/server/coordinator/duty/KillUnusedSegments.java
index 3b552f00acf2..77abee91c980 100644
--- a/server/src/main/java/org/apache/druid/server/coordinator/duty/KillUnusedSegments.java
+++ b/server/src/main/java/org/apache/druid/server/coordinator/duty/KillUnusedSegments.java
@@ -231,7 +231,6 @@ private void killUnusedSegments(
         ++submittedTasks;
         datasourceToLastKillIntervalEnd.put(dataSource, intervalToKill.getEnd());
 
-        // Check for termination conditions.
         if (remainingDatasourcesToKill.isEmpty() || submittedTasks >= availableKillTaskSlots) {
           break;
         }
diff --git a/server/src/test/java/org/apache/druid/server/coordinator/duty/KillUnusedSegmentsTest.java b/server/src/test/java/org/apache/druid/server/coordinator/duty/KillUnusedSegmentsTest.java
index e2cbbdf5e434..bdb7a773b09d 100644
--- a/server/src/test/java/org/apache/druid/server/coordinator/duty/KillUnusedSegmentsTest.java
+++ b/server/src/test/java/org/apache/druid/server/coordinator/duty/KillUnusedSegmentsTest.java
@@ -556,7 +556,7 @@ public void testLowerMaxSegmentsToKill()
   }
 
   @Test
-  public void testDatasourcesFoundButNoUnusedSegments()
+  public void testKillDatasourceWithNoUnusedSegmentsInInitialRun()
   {
     configBuilder.withMaxSegmentsToKill(1);
 
@@ -643,10 +643,10 @@ public void testKillTaskSlotAtCapacity()
 
     initDuty();
     final CoordinatorRunStats stats = runDutyAndGetStats();
+
     Assert.assertEquals(2, stats.get(Stats.Kill.AVAILABLE_SLOTS));
     Assert.assertEquals(2, stats.get(Stats.Kill.SUBMITTED_TASKS));
     Assert.assertEquals(2, stats.get(Stats.Kill.MAX_SLOTS));
-
     Assert.assertEquals(2, stats.get(Stats.Kill.ELIGIBLE_UNUSED_SEGMENTS, DS1_STAT_KEY));
     Assert.assertEquals(1, stats.get(Stats.Kill.ELIGIBLE_UNUSED_SEGMENTS, DS2_STAT_KEY));