Refactor GetStats, FlushStats and QueryCacheStats with Builder pattern

CHANGELOG.md

@@ -46,6 +46,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Pass registry of headers from ActionPlugin.getRestHeaders to ActionPlugin.getRestHandlerWrapper ([#19875](https://github.com/opensearch-project/OpenSearch/pull/19875))
 - Refactor the Condition.Stats and DirectoryFileTransferTracker.Stats class to use the Builder pattern instead of constructors ([#19862](https://github.com/opensearch-project/OpenSearch/pull/19862))
 - Refactor the RemoteTranslogTransferTracker.Stats and RemoteSegmentTransferTracker.Stats class to use the Builder pattern instead of constructors ([#19837](https://github.com/opensearch-project/OpenSearch/pull/19837))
+- Refactor the GetStats, FlushStats and QueryCacheStats class to use the Builder pattern instead of constructors ([#19935](https://github.com/opensearch-project/OpenSearch/pull/19935))
 
 ### Fixed
 - Fix Allocation and Rebalance Constraints of WeightFunction are incorrectly reset ([#19012](https://github.com/opensearch-project/OpenSearch/pull/19012))
@@ -96,6 +97,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Deprecated existing constructors in DocStats and StoreStats in favor of the new Builder ([#19863](https://github.com/opensearch-project/OpenSearch/pull/19863))
 - Deprecated existing constructors in Condition.Stats and DirectoryFileTransferTracker.Stats in favor of the new Builder ([#19862](https://github.com/opensearch-project/OpenSearch/pull/19862))
 - Deprecated existing constructors in RemoteTranslogTransferTracker.Stats and RemoteSegmentTransferTracker.Stats in favor of the new Builder ([#19837](https://github.com/opensearch-project/OpenSearch/pull/19837))
+- Deprecated existing constructors in GetStats, FlushStats and QueryCacheStats in favor of the new Builder ([#19935](https://github.com/opensearch-project/OpenSearch/pull/19935))
 
 ### Removed
 

server/src/main/java/org/opensearch/index/cache/query/QueryCacheStats.java

@@ -60,6 +60,19 @@ public class QueryCacheStats implements Writeable, ToXContentFragment {
 
     public QueryCacheStats() {}
 
+    /**
+     * Private constructor that takes a builder.
+     * This is the sole entry point for creating a new QueryCacheStats object.
+     * @param builder The builder instance containing all the values.
+     */
+    private QueryCacheStats(Builder builder) {
+        this.ramBytesUsed = builder.ramBytesUsed;
+        this.hitCount = builder.hitCount;
+        this.missCount = builder.missCount;
+        this.cacheCount = builder.cacheCount;
+        this.cacheSize = builder.cacheSize;
+    }
+
     public QueryCacheStats(StreamInput in) throws IOException {
         ramBytesUsed = in.readLong();
         hitCount = in.readLong();
@@ -68,6 +81,11 @@ public QueryCacheStats(StreamInput in) throws IOException {
         cacheSize = in.readLong();
     }
 
+    /**
+     * This constructor will be deprecated starting in version 3.4.0.
+     * Use {@link Builder} instead.
+     */
+    @Deprecated
     public QueryCacheStats(long ramBytesUsed, long hitCount, long missCount, long cacheCount, long cacheSize) {
         this.ramBytesUsed = ramBytesUsed;
         this.hitCount = hitCount;
@@ -137,6 +155,53 @@ public long getEvictions() {
         return cacheCount - cacheSize;
     }
 
+    /**
+     * Builder for the {@link QueryCacheStats} class.
+     * Provides a fluent API for constructing a QueryCacheStats object.
+     */
+    public static class Builder {
+        private long ramBytesUsed = 0;
+        private long hitCount = 0;
+        private long missCount = 0;
+        private long cacheCount = 0;
+        private long cacheSize = 0;
+
+        public Builder() {}
+
+        public Builder ramBytesUsed(long used) {
+            this.ramBytesUsed = used;
+            return this;
+        }
+
+        public Builder hitCount(long count) {
+            this.hitCount = count;
+            return this;
+        }
+
+        public Builder missCount(long count) {
+            this.missCount = count;
+            return this;
+        }
+
+        public Builder cacheCount(long count) {
+            this.cacheCount = count;
+            return this;
+        }
+
+        public Builder cacheSize(long size) {
+            this.cacheSize = size;
+            return this;
+        }
+
+        /**
+         * Creates a {@link QueryCacheStats} object from the builder's current state.
+         * @return A new QueryCacheStats instance.
+         */
+        public QueryCacheStats build() {
+            return new QueryCacheStats(this);
+        }
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeLong(ramBytesUsed);

server/src/main/java/org/opensearch/index/flush/FlushStats.java

@@ -58,12 +58,28 @@ public FlushStats() {
 
     }
 
+    /**
+     * Private constructor that takes a builder.
+     * This is the sole entry point for creating a new FlushStats object.
+     * @param builder The builder instance containing all the values.
+     */
+    private FlushStats(Builder builder) {
+        this.total = builder.total;
+        this.periodic = builder.periodic;
+        this.totalTimeInMillis = builder.totalTimeInMillis;
+    }
+
     public FlushStats(StreamInput in) throws IOException {
         total = in.readVLong();
         totalTimeInMillis = in.readVLong();
         periodic = in.readVLong();
     }
 
+    /**
+     * This constructor will be deprecated starting in version 3.4.0.
+     * Use {@link Builder} instead.
+     */
+    @Deprecated
     public FlushStats(long total, long periodic, long totalTimeInMillis) {
         this.total = total;
         this.periodic = periodic;
@@ -117,6 +133,42 @@ public TimeValue getTotalTime() {
         return new TimeValue(totalTimeInMillis);
     }
 
+    /**
+     * Builder for the {@link FlushStats} class.
+     * Provides a fluent API for constructing a FlushStats object.
+     */
+    public static class Builder {
+        private long total = 0;
+        private long periodic = 0;
+        private long totalTimeInMillis = 0;
+
+        public Builder() {}
+
+        public Builder total(long total) {
+            this.total = total;
+            return this;
+        }
+
+        public Builder periodic(long periodic) {
+            this.periodic = periodic;
+            return this;
+        }
+
+        public Builder totalTimeInMillis(long time) {
+            this.totalTimeInMillis = time;
+            return this;
+        }
+
+        /**
+         * Creates a {@link FlushStats} object from the builder's current state.
+         *
+         * @return A new FlushStats instance.
+         */
+        public FlushStats build() {
+            return new FlushStats(this);
+        }
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(Fields.FLUSH);

server/src/main/java/org/opensearch/index/get/GetStats.java

@@ -59,6 +59,19 @@ public class GetStats implements Writeable, ToXContentFragment {
 
     public GetStats() {}
 
+    /**
+     * Private constructor that takes a builder.
+     * This is the sole entry point for creating a new GetStats object.
+     * @param builder The builder instance containing all the values.
+     */
+    private GetStats(Builder builder) {
+        this.existsCount = builder.existsCount;
+        this.existsTimeInMillis = builder.existsTimeInMillis;
+        this.missingCount = builder.missingCount;
+        this.missingTimeInMillis = builder.missingTimeInMillis;
+        this.current = builder.current;
+    }
+
     public GetStats(StreamInput in) throws IOException {
         existsCount = in.readVLong();
         existsTimeInMillis = in.readVLong();
@@ -67,6 +80,11 @@ public GetStats(StreamInput in) throws IOException {
         current = in.readVLong();
     }
 
+    /**
+     * This constructor will be deprecated starting in version 3.4.0.
+     * Use {@link Builder} instead.
+     */
+    @Deprecated
     public GetStats(long existsCount, long existsTimeInMillis, long missingCount, long missingTimeInMillis, long current) {
         this.existsCount = existsCount;
         this.existsTimeInMillis = existsTimeInMillis;
@@ -134,6 +152,54 @@ public long current() {
         return this.current;
     }
 
+    /**
+     * Builder for the {@link GetStats} class.
+     * Provides a fluent API for constructing a GetStats object.
+     */
+    public static class Builder {
+        private long existsCount = 0;
+        private long existsTimeInMillis = 0;
+        private long missingCount = 0;
+        private long missingTimeInMillis = 0;
+        private long current = 0;
+
+        public Builder() {}
+
+        public Builder existsCount(long count) {
+            this.existsCount = count;
+            return this;
+        }
+
+        public Builder existsTimeInMillis(long time) {
+            this.existsTimeInMillis = time;
+            return this;
+        }
+
+        public Builder missingCount(long count) {
+            this.missingCount = count;
+            return this;
+        }
+
+        public Builder missingTimeInMillis(long time) {
+            this.missingTimeInMillis = time;
+            return this;
+        }
+
+        public Builder current(long current) {
+            this.current = current;
+            return this;
+        }
+
+        /**
+         * Creates a {@link GetStats} object from the builder's current state.
+         *
+         * @return A new GetStats instance.
+         */
+        public GetStats build() {
+            return new GetStats(this);
+        }
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(Fields.GET);

server/src/main/java/org/opensearch/index/get/ShardGetService.java

@@ -107,13 +107,12 @@ public ShardGetService(IndexSettings indexSettings, IndexShard indexShard, Mappe
     }
 
     public GetStats stats() {
-        return new GetStats(
-            existsMetric.count(),
-            TimeUnit.NANOSECONDS.toMillis(existsMetric.sum()),
-            missingMetric.count(),
-            TimeUnit.NANOSECONDS.toMillis(missingMetric.sum()),
-            currentMetric.count()
-        );
+        return new GetStats.Builder().existsCount(existsMetric.count())
+            .existsTimeInMillis(TimeUnit.NANOSECONDS.toMillis(existsMetric.sum()))
+            .missingCount(missingMetric.count())
+            .missingTimeInMillis(TimeUnit.NANOSECONDS.toMillis(missingMetric.sum()))
+            .current(currentMetric.count())
+            .build();
     }
 
     public GetResult get(

server/src/main/java/org/opensearch/index/shard/IndexShard.java

@@ -1513,7 +1513,10 @@ public RefreshStats refreshStats() {
     }
 
     public FlushStats flushStats() {
-        return new FlushStats(flushMetric.count(), periodicFlushMetric.count(), TimeUnit.NANOSECONDS.toMillis(flushMetric.sum()));
+        return new FlushStats.Builder().total(flushMetric.count())
+            .periodic(periodicFlushMetric.count())
+            .totalTimeInMillis(TimeUnit.NANOSECONDS.toMillis(flushMetric.sum()))
+            .build();
     }
 
     public DocsStats docStats() {

server/src/main/java/org/opensearch/indices/IndicesQueryCache.java

@@ -183,15 +183,24 @@ public QueryCacheStats getStats(ShardId shard) {
         // We also have some shared ram usage that we try to distribute to
         // proportionally to their number of cache entries of each shard
         if (stats.isEmpty()) {
-            shardStats.add(new QueryCacheStats(sharedRamBytesUsed, 0, 0, 0, 0));
+            shardStats.add(
+                new QueryCacheStats.Builder().ramBytesUsed(sharedRamBytesUsed).hitCount(0).missCount(0).cacheCount(0).cacheSize(0).build()
+            );
         } else {
             long totalSize = 0;
             for (QueryCacheStats s : stats.values()) {
                 totalSize += s.getCacheSize();
             }
             final double weight = totalSize == 0 ? 1d / stats.size() : ((double) shardStats.getCacheSize()) / totalSize;
             final long additionalRamBytesUsed = Math.round(weight * sharedRamBytesUsed);
-            shardStats.add(new QueryCacheStats(additionalRamBytesUsed, 0, 0, 0, 0));
+            shardStats.add(
+                new QueryCacheStats.Builder().ramBytesUsed(additionalRamBytesUsed)
+                    .hitCount(0)
+                    .missCount(0)
+                    .cacheCount(0)
+                    .cacheSize(0)
+                    .build()
+            );
         }
         return shardStats;
     }
@@ -287,7 +296,12 @@ private static class Stats implements Cloneable {
         }
 
         QueryCacheStats toQueryCacheStats() {
-            return new QueryCacheStats(ramBytesUsed, hitCount, missCount, cacheCount, cacheSize);
+            return new QueryCacheStats.Builder().ramBytesUsed(ramBytesUsed)
+                .hitCount(hitCount)
+                .missCount(missCount)
+                .cacheCount(cacheCount)
+                .cacheSize(cacheSize)
+                .build();
         }
 
         @Override

server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodeStatsTests.java

@@ -1372,15 +1372,17 @@ private CommonStats createRandomCommonStats() {
             .build();
         commonStats.indexing = new IndexingStats();
         commonStats.completion = new CompletionStats();
-        commonStats.flush = new FlushStats(randomLongBetween(0, 100), randomLongBetween(0, 100), randomLongBetween(0, 100));
+        commonStats.flush = new FlushStats.Builder().total(randomLongBetween(0, 100))
+            .periodic(randomLongBetween(0, 100))
+            .totalTimeInMillis(randomLongBetween(0, 100))
+            .build();
         commonStats.fieldData = new FieldDataStats(randomLongBetween(0, 100), randomLongBetween(0, 100), null);
-        commonStats.queryCache = new QueryCacheStats(
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100)
-        );
+        commonStats.queryCache = new QueryCacheStats.Builder().ramBytesUsed(randomLongBetween(0, 100))
+            .hitCount(randomLongBetween(0, 100))
+            .missCount(randomLongBetween(0, 100))
+            .cacheCount(randomLongBetween(0, 100))
+            .cacheSize(randomLongBetween(0, 100))
+            .build();
         commonStats.segments = new SegmentsStats();
 
         return commonStats;

server/src/test/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodesTests.java

@@ -371,15 +371,17 @@ private CommonStats createRandomCommonStats() {
             .build();
         commonStats.indexing = new IndexingStats();
         commonStats.completion = new CompletionStats();
-        commonStats.flush = new FlushStats(randomLongBetween(0, 100), randomLongBetween(0, 100), randomLongBetween(0, 100));
+        commonStats.flush = new FlushStats.Builder().total(randomLongBetween(0, 100))
+            .periodic(randomLongBetween(0, 100))
+            .totalTimeInMillis(randomLongBetween(0, 100))
+            .build();
         commonStats.fieldData = new FieldDataStats(randomLongBetween(0, 100), randomLongBetween(0, 100), null);
-        commonStats.queryCache = new QueryCacheStats(
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100),
-            randomLongBetween(0, 100)
-        );
+        commonStats.queryCache = new QueryCacheStats.Builder().ramBytesUsed(randomLongBetween(0, 100))
+            .hitCount(randomLongBetween(0, 100))
+            .missCount(randomLongBetween(0, 100))
+            .cacheCount(randomLongBetween(0, 100))
+            .cacheSize(randomLongBetween(0, 100))
+            .build();
         commonStats.segments = new SegmentsStats();
 
         return commonStats;