From 11eb0cc317771bdd78c61d01d712b62014f662b2 Mon Sep 17 00:00:00 2001
From: Uwe Schindler <uschindler@apache.org>
Date: Fri, 29 Mar 2024 14:21:11 +0100
Subject: [PATCH] Optimization: Use precalculated IOContexts for
 withReadAdvice() to not create new instances all the time (#13245)

---
 lucene/core/src/java/org/apache/lucene/store/IOContext.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lucene/core/src/java/org/apache/lucene/store/IOContext.java b/lucene/core/src/java/org/apache/lucene/store/IOContext.java
index 860c5f9f6e5..f5b170ddd1f 100644
--- a/lucene/core/src/java/org/apache/lucene/store/IOContext.java
+++ b/lucene/core/src/java/org/apache/lucene/store/IOContext.java
@@ -16,6 +16,7 @@
  */
 package org.apache.lucene.store;
 
+import java.util.Arrays;
 import java.util.Objects;
 
 /**
@@ -49,6 +50,9 @@ public record IOContext(
 
   public static final IOContext READONCE = new IOContext(ReadAdvice.SEQUENTIAL);
 
+  private static final IOContext[] DEFAULT_READADVICE_CACHE =
+      Arrays.stream(ReadAdvice.values()).map(IOContext::new).toArray(IOContext[]::new);
+
   @SuppressWarnings("incomplete-switch")
   public IOContext {
     Objects.requireNonNull(context, "context must not be null");
@@ -93,7 +97,7 @@ public record IOContext(
    */
   public IOContext withReadAdvice(ReadAdvice advice) {
     if (context == Context.DEFAULT) {
-      return new IOContext(advice);
+      return DEFAULT_READADVICE_CACHE[advice.ordinal()];
     } else {
       return this;
     }