Add hasNoSlots() method to RedisClusterNode (#3015)

src/main/java/io/lettuce/core/cluster/models/partitions/RedisClusterNode.java

@@ -45,6 +45,7 @@
  *
  * @author Mark Paluch
  * @author Alessandro Simi
+ * @author Tony Zhang
  * @since 3.0
  */
 @SuppressWarnings("serial")
@@ -294,6 +295,15 @@ public List<Integer> getSlots() {
         return slots;
     }
 
+    /**
+     * Checks if the node has no slots assigned.
+     *
+     * @return {@code true} if the slots field is null or empty, {@code false} otherwise.
+     */
+    public boolean hasNoSlots() {
+        return slots == null || slots.isEmpty();
+    }
+
     /**
      * Performs the given action for each slot of this {@link RedisClusterNode} until all elements have been processed or the
      * action throws an exception. Unless otherwise specified by the implementing class, actions are performed in the order of

src/test/java/io/lettuce/core/cluster/models/partitions/RedisClusterNodeUnitTests.java

@@ -140,4 +140,35 @@ void testToString() {
         assertThat(node.toString()).contains(RedisClusterNode.class.getSimpleName());
     }
 
+    @Test
+    void shouldReturnTrueWhenSlotsAreNull() {
+
+        BitSet emptySlots = null;
+        RedisClusterNode node = new RedisClusterNode(RedisURI.create("localhost", 6379), "1", true, null, 0, 0, 0, emptySlots,
+                Collections.emptySet());
+
+        assertThat(node.hasNoSlots()).isTrue();
+    }
+
+    @Test
+    void shouldReturnTrueWhenSlotsAreEmpty() {
+
+        BitSet emptySlots = new BitSet(); // Empty BitSet
+        RedisClusterNode node = new RedisClusterNode(RedisURI.create("localhost", 6379), "1", true, null, 0, 0, 0, emptySlots,
+                Collections.emptySet());
+
+        assertThat(node.hasNoSlots()).isTrue();
+    }
+
+    @Test
+    void shouldReturnFalseWhenSlotsAreAssigned() {
+
+        BitSet slots = new BitSet();
+        slots.set(1); // Assign a slot
+        RedisClusterNode node = new RedisClusterNode(RedisURI.create("localhost", 6379), "1", true, null, 0, 0, 0, slots,
+                Collections.emptySet());
+
+        assertThat(node.hasNoSlots()).isFalse();
+    }
+
 }