added utilitly fns to CacheStatsResponse

Signed-off-by: Peter Alfonsi <[email protected]>

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

@@ -8,15 +8,17 @@
 
 package org.opensearch.common.cache.stats;
 
+import java.util.Objects;
+
 /**
  * A class containing the 5 metrics tracked by a CacheStats object.
  */
 public class CacheStatsResponse { // TODO: Make this extend ToXContent.
-    public final long hits;
-    public final long misses;
-    public final long evictions;
-    public final long memorySize;
-    public final long entries;
+    public long hits;
+    public long misses;
+    public long evictions;
+    public long memorySize;
+    public long entries;
 
     public CacheStatsResponse(long hits, long misses, long evictions, long memorySize, long entries) {
         this.hits = hits;
@@ -25,4 +27,44 @@ public CacheStatsResponse(long hits, long misses, long evictions, long memorySiz
         this.memorySize = memorySize;
         this.entries = entries;
     }
+
+    public CacheStatsResponse() {
+        this.hits = 0;
+        this.misses = 0;
+        this.evictions = 0;
+        this.memorySize = 0;
+        this.entries = 0;
+    }
+
+    public void add(CacheStatsResponse other) {
+        if (other == null) {
+            return;
+        }
+        this.hits += other.hits;
+        this.misses += other.misses;
+        this.evictions += other.evictions;
+        this.memorySize += other.memorySize;
+        this.entries += other.entries;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null) {
+            return false;
+        }
+        if (o.getClass() != CacheStatsResponse.class) {
+            return false;
+        }
+        CacheStatsResponse other = (CacheStatsResponse) o;
+        return (hits == other.hits)
+            && (misses == other.misses)
+            && (evictions == other.evictions)
+            && (memorySize == other.memorySize)
+            && (entries == other.entries);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(hits, misses, evictions, memorySize, entries);
+    }
 }