Renamed snapshot -> ImmutableCacheStats

Signed-off-by: Peter Alfonsi <petealft@amazon.com>

plugins/cache-ehcache/src/test/java/org/opensearch/cache/store/disk/EhCacheDiskCacheTests.java

@@ -20,7 +20,7 @@
 import org.opensearch.common.cache.RemovalNotification;
 import org.opensearch.common.cache.serializer.BytesReferenceSerializer;
 import org.opensearch.common.cache.serializer.Serializer;
-import org.opensearch.common.cache.stats.CacheStatsSnapshot;
+import org.opensearch.common.cache.stats.ImmutableCacheStats;
 import org.opensearch.common.cache.store.config.CacheConfig;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.settings.Settings;
@@ -828,7 +828,7 @@ public void testInvalidateWithDropDimensions() throws Exception {
 
             ICacheKey<String> keyToDrop = keysAdded.get(0);
 
-            CacheStatsSnapshot snapshot = ehCacheDiskCachingTier.stats().getStatsForDimensionValues(keyToDrop.dimensions);
+            ImmutableCacheStats snapshot = ehCacheDiskCachingTier.stats().getStatsForDimensionValues(keyToDrop.dimensions);
             assertNotNull(snapshot);
 
             keyToDrop.setDropStatsForDimensions(true);

server/src/main/java/org/opensearch/common/cache/stats/CacheStats.java

@@ -54,14 +54,14 @@ public void add(CacheStats other) {
         internalAdd(other.getHits(), other.getMisses(), other.getEvictions(), other.getSizeInBytes(), other.getEntries());
     }
 
-    public void add(CacheStatsSnapshot snapshot) {
+    public void add(ImmutableCacheStats snapshot) {
         if (snapshot == null) {
             return;
         }
         internalAdd(snapshot.getHits(), snapshot.getMisses(), snapshot.getEvictions(), snapshot.getSizeInBytes(), snapshot.getEntries());
     }
 
-    public void subtract(CacheStatsSnapshot other) {
+    public void subtract(ImmutableCacheStats other) {
         if (other == null) {
             return;
         }
@@ -126,7 +126,7 @@ public void resetSizeAndEntries() {
         entries = new CounterMetric();
     }
 
-    public CacheStatsSnapshot snapshot() {
-        return new CacheStatsSnapshot(hits.count(), misses.count(), evictions.count(), sizeInBytes.count(), entries.count());
+    public ImmutableCacheStats immutableSnapshot() {
+        return new ImmutableCacheStats(hits.count(), misses.count(), evictions.count(), sizeInBytes.count(), entries.count());
     }
 }

server/src/main/java/org/opensearch/common/cache/stats/CacheStatsHolder.java

@@ -156,7 +156,7 @@ private boolean internalIncrementHelper(
      * Produce an immutable version of these stats.
      */
     public ImmutableCacheStatsHolder getImmutableCacheStatsHolder() {
-        ImmutableCacheStatsHolder.Node snapshot = new ImmutableCacheStatsHolder.Node("", true, statsRoot.getStatsSnapshot());
+        ImmutableCacheStatsHolder.Node snapshot = new ImmutableCacheStatsHolder.Node("", true, statsRoot.getImmutableStats());
         // Traverse the tree and build a corresponding tree of MDCSDimensionNode, to pass to MultiDimensionCacheStats.
         if (statsRoot.getChildren() != null) {
             for (Node child : statsRoot.getChildren().values()) {
@@ -175,9 +175,9 @@ private void getImmutableCacheStatsHelper(Node currentNodeInOriginalTree, Immuta
     }
 
     private ImmutableCacheStatsHolder.Node createMatchingImmutableCacheStatsHolderNode(Node node) {
-        CacheStatsSnapshot nodeSnapshot = node.getStatsSnapshot();
+        ImmutableCacheStats immutableCacheStats = node.getImmutableStats();
         boolean isLeafNode = node.getChildren().isEmpty();
-        return new ImmutableCacheStatsHolder.Node(node.getDimensionValue(), !isLeafNode, nodeSnapshot);
+        return new ImmutableCacheStatsHolder.Node(node.getDimensionValue(), !isLeafNode, immutableCacheStats);
     }
 
     public void removeDimensions(List<String> dimensionValues) {
@@ -192,16 +192,16 @@ public void removeDimensions(List<String> dimensionValues) {
     }
 
     // Returns a CacheStatsCounterSnapshot object for the stats to decrement if the removal happened, null otherwise.
-    private CacheStatsSnapshot removeDimensionsHelper(List<String> dimensionValues, Node node, int depth) {
+    private ImmutableCacheStats removeDimensionsHelper(List<String> dimensionValues, Node node, int depth) {
         if (depth == dimensionValues.size()) {
             // Pass up a snapshot of the original stats to avoid issues when the original is decremented by other fn invocations
-            return node.getStatsSnapshot();
+            return node.getImmutableStats();
         }
         Node child = node.getChild(dimensionValues.get(depth));
         if (child == null) {
             return null;
         }
-        CacheStatsSnapshot statsToDecrement = removeDimensionsHelper(dimensionValues, child, depth + 1);
+        ImmutableCacheStats statsToDecrement = removeDimensionsHelper(dimensionValues, child, depth + 1);
         if (statsToDecrement != null) {
             // The removal took place, decrement values and remove this node from its parent if it's now empty
             node.decrementBySnapshot(statsToDecrement);
@@ -281,11 +281,11 @@ long getEntries() {
             return this.stats.getEntries();
         }
 
-        CacheStatsSnapshot getStatsSnapshot() {
-            return this.stats.snapshot();
+        ImmutableCacheStats getImmutableStats() {
+            return this.stats.immutableSnapshot();
         }
 
-        void decrementBySnapshot(CacheStatsSnapshot snapshot) {
+        void decrementBySnapshot(ImmutableCacheStats snapshot) {
             this.stats.subtract(snapshot);
         }
 

server/src/main/java/org/opensearch/common/cache/stats/CacheStatsSnapshot.java → server/src/main/java/org/opensearch/common/cache/stats/ImmutableCacheStats.java

@@ -22,27 +22,27 @@
  * @opensearch.experimental
  */
 @ExperimentalApi
-public class CacheStatsSnapshot implements Writeable { // TODO: Make this extend ToXContent (in API PR)
+public class ImmutableCacheStats implements Writeable { // TODO: Make this extend ToXContent (in API PR)
     private final long hits;
     private final long misses;
     private final long evictions;
     private final long sizeInBytes;
     private final long entries;
 
-    public CacheStatsSnapshot(long hits, long misses, long evictions, long sizeInBytes, long entries) {
+    public ImmutableCacheStats(long hits, long misses, long evictions, long sizeInBytes, long entries) {
         this.hits = hits;
         this.misses = misses;
         this.evictions = evictions;
         this.sizeInBytes = sizeInBytes;
         this.entries = entries;
     }
 
-    public CacheStatsSnapshot(StreamInput in) throws IOException {
+    public ImmutableCacheStats(StreamInput in) throws IOException {
         this(in.readVLong(), in.readVLong(), in.readVLong(), in.readVLong(), in.readVLong());
     }
 
-    public static CacheStatsSnapshot addSnapshots(CacheStatsSnapshot s1, CacheStatsSnapshot s2) {
-        return new CacheStatsSnapshot(
+    public static ImmutableCacheStats addSnapshots(ImmutableCacheStats s1, ImmutableCacheStats s2) {
+        return new ImmutableCacheStats(
             s1.hits + s2.hits,
             s1.misses + s2.misses,
             s1.evictions + s2.evictions,
@@ -85,10 +85,10 @@ public boolean equals(Object o) {
         if (o == null) {
             return false;
         }
-        if (o.getClass() != CacheStatsSnapshot.class) {
+        if (o.getClass() != ImmutableCacheStats.class) {
             return false;
         }
-        CacheStatsSnapshot other = (CacheStatsSnapshot) o;
+        ImmutableCacheStats other = (ImmutableCacheStats) o;
         return (hits == other.hits)
             && (misses == other.misses)
             && (evictions == other.evictions)

server/src/main/java/org/opensearch/common/cache/stats/ImmutableCacheStatsHolder.java

@@ -23,7 +23,7 @@
 
 @ExperimentalApi
 public class ImmutableCacheStatsHolder { // TODO: extends Writeable, ToXContent
-    // A snapshot of a StatsHolder containing stats maintained by the cache.
+    // An immutable snapshot of a stats within a CacheStatsHolder, containing all the stats maintained by the cache.
     // Pkg-private for testing.
     final Node statsRoot;
     final List<String> dimensionNames;
@@ -33,7 +33,7 @@ public ImmutableCacheStatsHolder(Node statsRoot, List<String> dimensionNames) {
         this.dimensionNames = dimensionNames;
     }
 
-    public CacheStatsSnapshot getTotalStats() {
+    public ImmutableCacheStats getTotalStats() {
         return statsRoot.getStats();
     }
 
@@ -57,7 +57,7 @@ public long getTotalEntries() {
         return getTotalStats().getEntries();
     }
 
-    public CacheStatsSnapshot getStatsForDimensionValues(List<String> dimensionValues) {
+    public ImmutableCacheStats getStatsForDimensionValues(List<String> dimensionValues) {
         Node current = statsRoot;
         for (String dimensionValue : dimensionValues) {
             current = current.children.get(dimensionValue);
@@ -75,10 +75,10 @@ static class Node {
 
         // The stats for this node. If a leaf node, corresponds to the stats for this combination of dimensions; if not,
         // contains the sum of its children's stats.
-        private CacheStatsSnapshot stats;
+        private ImmutableCacheStats stats;
         private static final Map<String, Node> EMPTY_CHILDREN_MAP = new HashMap<>();
 
-        Node(String dimensionValue, boolean createChildrenMap, CacheStatsSnapshot stats) {
+        Node(String dimensionValue, boolean createChildrenMap, ImmutableCacheStats stats) {
             this.dimensionValue = dimensionValue;
             if (createChildrenMap) {
                 this.children = new TreeMap<>(); // This map should be ordered to enforce a consistent order in API response
@@ -92,11 +92,11 @@ Map<String, Node> getChildren() {
             return children;
         }
 
-        public CacheStatsSnapshot getStats() {
+        public ImmutableCacheStats getStats() {
             return stats;
         }
 
-        public void setStats(CacheStatsSnapshot stats) {
+        public void setStats(ImmutableCacheStats stats) {
             this.stats = stats;
         }
 

server/src/test/java/org/opensearch/common/cache/stats/CacheStatsHolderTests.java

@@ -32,20 +32,20 @@ public void testAddAndGet() throws Exception {
         for (List<String> dimensionValues : expected.keySet()) {
             CacheStats expectedCounter = expected.get(dimensionValues);
 
-            CacheStatsSnapshot actualStatsHolder = CacheStatsHolderTests.getNode(dimensionValues, cacheStatsHolder.getStatsRoot())
-                .getStatsSnapshot();
-            CacheStatsSnapshot actualCacheStats = getNode(dimensionValues, cacheStatsHolder.getStatsRoot()).getStatsSnapshot();
+            ImmutableCacheStats actualStatsHolder = CacheStatsHolderTests.getNode(dimensionValues, cacheStatsHolder.getStatsRoot())
+                .getImmutableStats();
+            ImmutableCacheStats actualCacheStats = getNode(dimensionValues, cacheStatsHolder.getStatsRoot()).getImmutableStats();
 
-            assertEquals(expectedCounter.snapshot(), actualStatsHolder);
-            assertEquals(expectedCounter.snapshot(), actualCacheStats);
+            assertEquals(expectedCounter.immutableSnapshot(), actualStatsHolder);
+            assertEquals(expectedCounter.immutableSnapshot(), actualCacheStats);
         }
 
         // Check overall total matches
         CacheStats expectedTotal = new CacheStats();
         for (List<String> dims : expected.keySet()) {
             expectedTotal.add(expected.get(dims));
         }
-        assertEquals(expectedTotal.snapshot(), cacheStatsHolder.getStatsRoot().getStatsSnapshot());
+        assertEquals(expectedTotal.immutableSnapshot(), cacheStatsHolder.getStatsRoot().getImmutableStats());
 
         // Check sum of children stats are correct
         assertSumOfChildrenStats(cacheStatsHolder.getStatsRoot());
@@ -65,8 +65,8 @@ public void testReset() throws Exception {
             originalCounter.entries = new CounterMetric();
 
             CacheStatsHolder.Node node = getNode(dimensionValues, cacheStatsHolder.getStatsRoot());
-            CacheStatsSnapshot actual = node.getStatsSnapshot();
-            assertEquals(originalCounter.snapshot(), actual);
+            ImmutableCacheStats actual = node.getImmutableStats();
+            assertEquals(originalCounter.immutableSnapshot(), actual);
         }
     }
 
@@ -80,13 +80,13 @@ public void testDropStatsForDimensions() throws Exception {
             cacheStatsHolder.incrementHits(dims);
         }
 
-        assertEquals(3, cacheStatsHolder.getStatsRoot().getStatsSnapshot().getHits());
+        assertEquals(3, cacheStatsHolder.getStatsRoot().getImmutableStats().getHits());
 
         // When we invalidate A2, B2, we should lose the node for B2, but not B3 or A2.
 
         cacheStatsHolder.removeDimensions(List.of("A2", "B2"));
 
-        assertEquals(2, cacheStatsHolder.getStatsRoot().getStatsSnapshot().getHits());
+        assertEquals(2, cacheStatsHolder.getStatsRoot().getImmutableStats().getHits());
         assertNull(getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()));
         assertNotNull(getNode(List.of("A2"), cacheStatsHolder.getStatsRoot()));
         assertNotNull(getNode(List.of("A2", "B3"), cacheStatsHolder.getStatsRoot()));
@@ -95,14 +95,14 @@ public void testDropStatsForDimensions() throws Exception {
 
         cacheStatsHolder.removeDimensions(List.of("A1", "B1"));
 
-        assertEquals(1, cacheStatsHolder.getStatsRoot().getStatsSnapshot().getHits());
+        assertEquals(1, cacheStatsHolder.getStatsRoot().getImmutableStats().getHits());
         assertNull(getNode(List.of("A1", "B1"), cacheStatsHolder.getStatsRoot()));
         assertNull(getNode(List.of("A1"), cacheStatsHolder.getStatsRoot()));
 
         // When we invalidate the last node, all nodes should be deleted except the root node
 
         cacheStatsHolder.removeDimensions(List.of("A2", "B3"));
-        assertEquals(0, cacheStatsHolder.getStatsRoot().getStatsSnapshot().getHits());
+        assertEquals(0, cacheStatsHolder.getStatsRoot().getImmutableStats().getHits());
         assertEquals(0, cacheStatsHolder.getStatsRoot().children.size());
     }
 
@@ -156,12 +156,12 @@ public void testConcurrentRemoval() throws Exception {
         assertNull(getNode(List.of("A1"), cacheStatsHolder.getStatsRoot()));
         assertNotNull(getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()));
         assertEquals(
-            new CacheStatsSnapshot(0, 1, 0, 0, 0),
-            getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()).getStatsSnapshot()
+            new ImmutableCacheStats(0, 1, 0, 0, 0),
+            getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()).getImmutableStats()
         );
         assertEquals(
-            new CacheStatsSnapshot(1, 1, 0, 0, 0),
-            getNode(List.of("A2", "B3"), cacheStatsHolder.getStatsRoot()).getStatsSnapshot()
+            new ImmutableCacheStats(1, 1, 0, 0, 0),
+            getNode(List.of("A2", "B3"), cacheStatsHolder.getStatsRoot()).getImmutableStats()
         );
     }
 
@@ -256,9 +256,9 @@ private void assertSumOfChildrenStats(CacheStatsHolder.Node current) {
         if (!current.children.isEmpty()) {
             CacheStats expectedTotal = new CacheStats();
             for (CacheStatsHolder.Node child : current.children.values()) {
-                expectedTotal.add(child.getStatsSnapshot());
+                expectedTotal.add(child.getImmutableStats());
             }
-            assertEquals(expectedTotal.snapshot(), current.getStatsSnapshot());
+            assertEquals(expectedTotal.immutableSnapshot(), current.getImmutableStats());
             for (CacheStatsHolder.Node child : current.children.values()) {
                 assertSumOfChildrenStats(child);
             }

server/src/test/java/org/opensearch/common/cache/stats/ImmutableCacheStatsHolderTests.java

@@ -26,20 +26,20 @@ public void testGet() throws Exception {
         for (List<String> dimensionValues : expected.keySet()) {
             CacheStats expectedCounter = expected.get(dimensionValues);
 
-            CacheStatsSnapshot actualStatsHolder = CacheStatsHolderTests.getNode(dimensionValues, cacheStatsHolder.getStatsRoot())
-                .getStatsSnapshot();
-            CacheStatsSnapshot actualCacheStats = getNode(dimensionValues, stats.getStatsRoot()).getStats();
+            ImmutableCacheStats actualStatsHolder = CacheStatsHolderTests.getNode(dimensionValues, cacheStatsHolder.getStatsRoot())
+                .getImmutableStats();
+            ImmutableCacheStats actualCacheStats = getNode(dimensionValues, stats.getStatsRoot()).getStats();
 
-            assertEquals(expectedCounter.snapshot(), actualStatsHolder);
-            assertEquals(expectedCounter.snapshot(), actualCacheStats);
+            assertEquals(expectedCounter.immutableSnapshot(), actualStatsHolder);
+            assertEquals(expectedCounter.immutableSnapshot(), actualCacheStats);
         }
 
         // test gets for total (this also checks sum-of-children logic)
         CacheStats expectedTotal = new CacheStats();
         for (List<String> dims : expected.keySet()) {
             expectedTotal.add(expected.get(dims));
         }
-        assertEquals(expectedTotal.snapshot(), stats.getTotalStats());
+        assertEquals(expectedTotal.immutableSnapshot(), stats.getTotalStats());
 
         assertEquals(expectedTotal.getHits(), stats.getTotalHits());
         assertEquals(expectedTotal.getMisses(), stats.getTotalMisses());
@@ -79,7 +79,7 @@ private void assertSumOfChildrenStats(ImmutableCacheStatsHolder.Node current) {
             for (ImmutableCacheStatsHolder.Node child : current.children.values()) {
                 expectedTotal.add(child.getStats());
             }
-            assertEquals(expectedTotal.snapshot(), current.getStats());
+            assertEquals(expectedTotal.immutableSnapshot(), current.getStats());
             for (ImmutableCacheStatsHolder.Node child : current.children.values()) {
                 assertSumOfChildrenStats(child);
             }

server/src/test/java/org/opensearch/common/cache/store/OpenSearchOnHeapCacheTests.java

@@ -15,7 +15,7 @@
 import org.opensearch.common.cache.LoadAwareCacheLoader;
 import org.opensearch.common.cache.RemovalListener;
 import org.opensearch.common.cache.RemovalNotification;
-import org.opensearch.common.cache.stats.CacheStatsSnapshot;
+import org.opensearch.common.cache.stats.ImmutableCacheStats;
 import org.opensearch.common.cache.store.config.CacheConfig;
 import org.opensearch.common.cache.store.settings.OpenSearchOnHeapCacheSettings;
 import org.opensearch.common.metrics.CounterMetric;
@@ -114,7 +114,7 @@ public void testInvalidateWithDropDimensions() throws Exception {
 
         ICacheKey<String> keyToDrop = keysAdded.get(0);
 
-        CacheStatsSnapshot snapshot = cache.stats().getStatsForDimensionValues(keyToDrop.dimensions);
+        ImmutableCacheStats snapshot = cache.stats().getStatsForDimensionValues(keyToDrop.dimensions);
         assertNotNull(snapshot);
 
         keyToDrop.setDropStatsForDimensions(true);