From 311c091a37c2e7eb907230bc0ade078b49f2ae29 Mon Sep 17 00:00:00 2001
From: "Kenneth J. Shackleton" <kshackleton1@bloomberg.net>
Date: Sat, 1 Jun 2024 12:48:11 +0100
Subject: [PATCH] JMH benchmark for LruCache.

Signed-off-by: Kenneth J. Shackleton <kshackleton1@bloomberg.net>
---
 .../cache/benchmarks/LruCacheBenchmark.kt     | 51 +++++++++++++++++++
 .../com/bloomberg/selekt/SQLConnection.kt     |  1 +
 .../bloomberg/selekt/{ => cache}/LruCache.kt  |  9 ++--
 .../com/bloomberg/selekt/LruCacheTest.kt      |  1 +
 4 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 selekt-java/src/jmh/kotlin/com/bloomberg/selekt/cache/benchmarks/LruCacheBenchmark.kt
 rename selekt-java/src/main/kotlin/com/bloomberg/selekt/{ => cache}/LruCache.kt (83%)

diff --git a/selekt-java/src/jmh/kotlin/com/bloomberg/selekt/cache/benchmarks/LruCacheBenchmark.kt b/selekt-java/src/jmh/kotlin/com/bloomberg/selekt/cache/benchmarks/LruCacheBenchmark.kt
new file mode 100644
index 0000000000..9ae099b5e4
--- /dev/null
+++ b/selekt-java/src/jmh/kotlin/com/bloomberg/selekt/cache/benchmarks/LruCacheBenchmark.kt
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2024 Bloomberg Finance L.P.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.bloomberg.selekt.cache.benchmarks
+
+import com.bloomberg.selekt.cache.LruCache
+import org.openjdk.jmh.annotations.Benchmark
+import org.openjdk.jmh.annotations.BenchmarkMode
+import org.openjdk.jmh.annotations.Level
+import org.openjdk.jmh.annotations.Mode
+import org.openjdk.jmh.annotations.Scope
+import org.openjdk.jmh.annotations.Setup
+import org.openjdk.jmh.annotations.State
+
+@State(Scope.Thread)
+open class CacheInput {
+    internal lateinit var cache: LruCache<Any>
+
+    @Setup(Level.Iteration)
+    fun setUp() {
+        cache = LruCache(1) {}
+    }
+}
+
+open class LruCacheBenchmark {
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    fun getEntry(input: CacheInput) = input.cache.run {
+        this["1", {}]
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    fun getEntryWithEviction(input: CacheInput) = input.cache.run {
+        this["1", {}]
+        this["2", {}]
+    }
+}
diff --git a/selekt-java/src/main/kotlin/com/bloomberg/selekt/SQLConnection.kt b/selekt-java/src/main/kotlin/com/bloomberg/selekt/SQLConnection.kt
index 3bbb97edbb..4e71010efd 100644
--- a/selekt-java/src/main/kotlin/com/bloomberg/selekt/SQLConnection.kt
+++ b/selekt-java/src/main/kotlin/com/bloomberg/selekt/SQLConnection.kt
@@ -16,6 +16,7 @@
 
 package com.bloomberg.selekt
 
+import com.bloomberg.selekt.cache.LruCache
 import com.bloomberg.selekt.commons.forEachByPosition
 import com.bloomberg.selekt.commons.forUntil
 import javax.annotation.concurrent.NotThreadSafe
diff --git a/selekt-java/src/main/kotlin/com/bloomberg/selekt/LruCache.kt b/selekt-java/src/main/kotlin/com/bloomberg/selekt/cache/LruCache.kt
similarity index 83%
rename from selekt-java/src/main/kotlin/com/bloomberg/selekt/LruCache.kt
rename to selekt-java/src/main/kotlin/com/bloomberg/selekt/cache/LruCache.kt
index 30bf9a32ef..06a50e3a14 100644
--- a/selekt-java/src/main/kotlin/com/bloomberg/selekt/LruCache.kt
+++ b/selekt-java/src/main/kotlin/com/bloomberg/selekt/cache/LruCache.kt
@@ -14,15 +14,18 @@
  * limitations under the License.
  */
 
-package com.bloomberg.selekt
+package com.bloomberg.selekt.cache
 
 import javax.annotation.concurrent.NotThreadSafe
 
 private const val NO_RESIZE_LOAD_FACTOR = 1.1f
 
 @NotThreadSafe
-internal class LruCache<T : Any>(private val maxSize: Int, private val disposal: (T) -> Unit) {
-    private val store = object : LinkedHashMap<String, T>(maxSize, NO_RESIZE_LOAD_FACTOR, true) {
+class LruCache<T : Any>(private val maxSize: Int, private val disposal: (T) -> Unit) {
+    @PublishedApi
+    @JvmField
+    @JvmSynthetic
+    internal val store = object : LinkedHashMap<String, T>(maxSize, NO_RESIZE_LOAD_FACTOR, true) {
         override fun removeEldestEntry(eldest: MutableMap.MutableEntry<String, T>) = (size > maxSize).also {
             if (it) {
                 disposal(eldest.value)
diff --git a/selekt-java/src/test/kotlin/com/bloomberg/selekt/LruCacheTest.kt b/selekt-java/src/test/kotlin/com/bloomberg/selekt/LruCacheTest.kt
index cba2c475a3..7f7692499d 100644
--- a/selekt-java/src/test/kotlin/com/bloomberg/selekt/LruCacheTest.kt
+++ b/selekt-java/src/test/kotlin/com/bloomberg/selekt/LruCacheTest.kt
@@ -16,6 +16,7 @@
 
 package com.bloomberg.selekt
 
+import com.bloomberg.selekt.cache.LruCache
 import org.junit.jupiter.api.Test
 import org.mockito.kotlin.anyOrNull
 import org.mockito.kotlin.doReturn