From a473a9e7598161d74cbb027837943ab3f7c718f7 Mon Sep 17 00:00:00 2001
From: Sarthak Aggarwal <sarthagg@amazon.com>
Date: Sun, 3 Sep 2023 07:55:04 +0530
Subject: [PATCH] review comments

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>
---
 .../index/codec/customcodecs/Lucene95CustomCodec.java     | 4 ++--
 .../index/codec/customcodecs/CustomCodecTests.java        | 3 ---
 .../java/org/opensearch/index/codec/CodecAliases.java     | 8 +++++++-
 .../java/org/opensearch/index/engine/EngineConfig.java    | 4 ++--
 4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/plugins/custom-codecs/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomCodec.java b/plugins/custom-codecs/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomCodec.java
index 27c69db6f537f..a777ce781d518 100644
--- a/plugins/custom-codecs/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomCodec.java
+++ b/plugins/custom-codecs/src/main/java/org/opensearch/index/codec/customcodecs/Lucene95CustomCodec.java
@@ -32,11 +32,11 @@ public enum Mode {
         /**
          * ZStandard mode with dictionary
          */
-        ZSTD("zstd"),
+        ZSTD("Lucene95CustomCodec"),
         /**
          * ZStandard mode without dictionary
          */
-        ZSTD_NO_DICT("zstdnodict");
+        ZSTD_NO_DICT("Lucene95CustomCodec");
 
         private final String codec;
 
diff --git a/plugins/custom-codecs/src/test/java/org/opensearch/index/codec/customcodecs/CustomCodecTests.java b/plugins/custom-codecs/src/test/java/org/opensearch/index/codec/customcodecs/CustomCodecTests.java
index 6ed936742957a..688d0b0557fce 100644
--- a/plugins/custom-codecs/src/test/java/org/opensearch/index/codec/customcodecs/CustomCodecTests.java
+++ b/plugins/custom-codecs/src/test/java/org/opensearch/index/codec/customcodecs/CustomCodecTests.java
@@ -113,9 +113,6 @@ public void testBestCompressionWithCompressionLevel() {
     }
 
     public void testLuceneCodecsWithCompressionLevel() {
-        String codecName = randomFrom(Codec.availableCodecs());
-        Codec codec = Codec.forName(codecName);
-
         final Settings customCodecSettings = Settings.builder()
             .put(INDEX_CODEC_COMPRESSION_LEVEL_SETTING.getKey(), randomIntBetween(1, 6))
             .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), randomFrom("zstd", "zstd_no_dict"))
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecAliases.java b/server/src/main/java/org/opensearch/index/codec/CodecAliases.java
index d9849f7e4c79b..74c4ccda575f9 100644
--- a/server/src/main/java/org/opensearch/index/codec/CodecAliases.java
+++ b/server/src/main/java/org/opensearch/index/codec/CodecAliases.java
@@ -13,10 +13,16 @@
 import java.util.Set;
 
 /**
- * This {@link CodecAliases} allows us to manage the settings with {@link Codec}.
+ * This {@link CodecAliases} to provide aliases for the {@link Codec}.
  *
  * @opensearch.internal
  */
 public interface CodecAliases {
+
+    /**
+     * Retrieves a set of aliases for an codec.
+     *
+     * @return A non-null set of alias strings. If no aliases are available, an empty set should be returned.
+     */
     Set<String> aliases();
 }
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
index ae2cce1272b9d..00f8ff6d3cd40 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
@@ -145,7 +145,7 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
                     Codec codec = Codec.forName(codecName);
                     if (codec instanceof CodecAliases) {
                         CodecAliases codecWithAlias = (CodecAliases) codec;
-                        if (codecWithAlias.aliases() != null && codecWithAlias.aliases().contains(s)) {
+                        if (codecWithAlias.aliases().contains(s)) {
                             return s;
                         }
                     }
@@ -208,7 +208,7 @@ private static void doValidateCodecSettings(final String codec) {
                     Codec availableCodec = Codec.forName(codecName);
                     if (availableCodec instanceof CodecAliases) {
                         CodecAliases availableCodecWithAlias = (CodecAliases) availableCodec;
-                        if (availableCodecWithAlias.aliases() != null && availableCodecWithAlias.aliases().contains(codec)) {
+                        if (availableCodecWithAlias.aliases().contains(codec)) {
                             if (availableCodec instanceof CodecSettings
                                 && ((CodecSettings) availableCodec).supports(INDEX_CODEC_COMPRESSION_LEVEL_SETTING)) {
                                 return;