Add Lucene 9.5 codec and make it new default

DEVELOPER_GUIDE.md

@@ -286,10 +286,12 @@ Before adding any new tests to Backward Compatibility Tests, we should be aware
 
 Starting from 2.0 release the new versioning for codec has been introduced. Two positions will be used to define the version,
 in format 'X.Y', where 'X' corresponds to underlying version of Lucene and 'Y' is the version of the format. 
+Please note that Lucene version along with corresponding Lucene codec is part of the core OpenSearch. KNN codec should be in sync with Lucene codec version from core OpenSearch.
 
 Codec version is used in following classes and methods:
 - org.opensearch.knn.index.codec.KNNXYCodec.KNNXYCodec
-- org.opensearch.knn.index.codec.KNNFormatFactory.createKNNXYFormat
+- org.opensearch.knn.index.codec.KNNXYCodec.KNNXYPerFieldKnnVectorsFormat
+- org.opensearch.knn.index.codec.KNNCodecVersion
 
 These classes and methods are tied directly to Lucene version represented by 'X' part. 
 Other classes use the delegate pattern so no direct tie to Lucene version are related to format and represented by 'Y'

src/main/java/org/opensearch/knn/index/codec/KNN950Codec/KNN950Codec.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.index.codec.KNN950Codec;
+
+import lombok.Builder;
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.CompoundFormat;
+import org.apache.lucene.codecs.DocValuesFormat;
+import org.apache.lucene.codecs.FilterCodec;
+import org.apache.lucene.codecs.KnnVectorsFormat;
+import org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat;
+import org.opensearch.knn.index.codec.KNNCodecVersion;
+import org.opensearch.knn.index.codec.KNNFormatFacade;
+
+public class KNN950Codec extends FilterCodec {
+    private static final KNNCodecVersion VERSION = KNNCodecVersion.V_9_5_0;
+    private final KNNFormatFacade knnFormatFacade;
+    private final PerFieldKnnVectorsFormat perFieldKnnVectorsFormat;
+
+    /**
+     * No arg constructor that uses Lucene95 as the delegate
+     */
+    public KNN950Codec() {
+        this(VERSION.getDefaultCodecDelegate(), VERSION.getPerFieldKnnVectorsFormat());
+    }
+
+    /**
+     * Sole constructor. When subclassing this codec, create a no-arg ctor and pass the delegate codec
+     * and a unique name to this ctor.
+     *
+     * @param delegate codec that will perform all operations this codec does not override
+     * @param knnVectorsFormat per field format for KnnVector
+     */
+    @Builder
+    protected KNN950Codec(Codec delegate, PerFieldKnnVectorsFormat knnVectorsFormat) {
+        super(VERSION.getCodecName(), delegate);
+        knnFormatFacade = VERSION.getKnnFormatFacadeSupplier().apply(delegate);
+        perFieldKnnVectorsFormat = knnVectorsFormat;
+    }
+
+    @Override
+    public DocValuesFormat docValuesFormat() {
+        return knnFormatFacade.docValuesFormat();
+    }
+
+    @Override
+    public CompoundFormat compoundFormat() {
+        return knnFormatFacade.compoundFormat();
+    }
+
+    @Override
+    public KnnVectorsFormat knnVectorsFormat() {
+        return perFieldKnnVectorsFormat;
+    }
+}

src/main/java/org/opensearch/knn/index/codec/KNN950Codec/KNN950PerFieldKnnVectorsFormat.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.index.codec.KNN950Codec;
+
+import org.apache.lucene.codecs.lucene95.Lucene95HnswVectorsFormat;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.knn.index.codec.BasePerFieldKnnVectorsFormat;
+
+import java.util.Optional;
+
+/**
+ * Class provides per field format implementation for Lucene Knn vector type
+ */
+public class KNN950PerFieldKnnVectorsFormat extends BasePerFieldKnnVectorsFormat {
+
+    public KNN950PerFieldKnnVectorsFormat(final Optional<MapperService> mapperService) {
+        super(
+            mapperService,
+            Lucene95HnswVectorsFormat.DEFAULT_MAX_CONN,
+            Lucene95HnswVectorsFormat.DEFAULT_BEAM_WIDTH,
+            () -> new Lucene95HnswVectorsFormat(),
+            (maxConnm, beamWidth) -> new Lucene95HnswVectorsFormat(maxConnm, beamWidth)
+        );
+    }
+}

src/main/java/org/opensearch/knn/index/codec/KNNCodecVersion.java

@@ -11,6 +11,7 @@
 import org.apache.lucene.backward_codecs.lucene92.Lucene92Codec;
 import org.apache.lucene.backward_codecs.lucene94.Lucene94Codec;
 import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.knn.index.codec.KNN80Codec.KNN80CompoundFormat;
@@ -20,6 +21,8 @@
 import org.opensearch.knn.index.codec.KNN920Codec.KNN920PerFieldKnnVectorsFormat;
 import org.opensearch.knn.index.codec.KNN940Codec.KNN940Codec;
 import org.opensearch.knn.index.codec.KNN940Codec.KNN940PerFieldKnnVectorsFormat;
+import org.opensearch.knn.index.codec.KNN950Codec.KNN950Codec;
+import org.opensearch.knn.index.codec.KNN950Codec.KNN950PerFieldKnnVectorsFormat;
 
 import java.util.Optional;
 import java.util.function.BiFunction;
@@ -74,9 +77,24 @@ public enum KNNCodecVersion {
             .knnVectorsFormat(new KNN940PerFieldKnnVectorsFormat(Optional.ofNullable(mapperService)))
             .build(),
         KNN940Codec::new
+    ),
+
+    V_9_5_0(
+        "KNN950Codec",
+        new Lucene95Codec(),
+        new KNN950PerFieldKnnVectorsFormat(Optional.empty()),
+        (delegate) -> new KNNFormatFacade(
+            new KNN80DocValuesFormat(delegate.docValuesFormat()),
+            new KNN80CompoundFormat(delegate.compoundFormat())
+        ),
+        (userCodec, mapperService) -> KNN950Codec.builder()
+            .delegate(userCodec)
+            .knnVectorsFormat(new KNN950PerFieldKnnVectorsFormat(Optional.ofNullable(mapperService)))
+            .build(),
+        KNN950Codec::new
     );
 
-    private static final KNNCodecVersion CURRENT = V_9_4_0;
+    private static final KNNCodecVersion CURRENT = V_9_5_0;
 
     private final String codecName;
     private final Codec defaultCodecDelegate;

src/main/resources/META-INF/services/org.apache.lucene.codecs.Codec

@@ -4,4 +4,5 @@ org.opensearch.knn.index.codec.KNN86Codec.KNN86Codec
 org.opensearch.knn.index.codec.KNN87Codec.KNN87Codec
 org.opensearch.knn.index.codec.KNN910Codec.KNN910Codec
 org.opensearch.knn.index.codec.KNN920Codec.KNN920Codec
-org.opensearch.knn.index.codec.KNN940Codec.KNN940Codec
+org.opensearch.knn.index.codec.KNN940Codec.KNN940Codec
+org.opensearch.knn.index.codec.KNN950Codec.KNN950Codec

src/test/java/org/opensearch/knn/index/codec/KNN950Codec/KNN950CodecTests.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.index.codec.KNN950Codec;
+
+import lombok.SneakyThrows;
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.knn.index.codec.KNNCodecTestCase;
+
+import java.util.Optional;
+import java.util.function.Function;
+
+import static org.opensearch.knn.index.codec.KNNCodecVersion.V_9_5_0;
+
+public class KNN950CodecTests extends KNNCodecTestCase {
+
+    @SneakyThrows
+    public void testMultiFieldsKnnIndex() {
+        testMultiFieldsKnnIndex(KNN950Codec.builder().delegate(V_9_5_0.getDefaultCodecDelegate()).build());
+    }
+
+    @SneakyThrows
+    public void testBuildFromModelTemplate() {
+        testBuildFromModelTemplate((KNN950Codec.builder().delegate(V_9_5_0.getDefaultCodecDelegate()).build()));
+    }
+
+    @SneakyThrows
+    public void testKnnVectorIndex() {
+        Function<MapperService, PerFieldKnnVectorsFormat> perFieldKnnVectorsFormatProvider = (
+            mapperService) -> new KNN950PerFieldKnnVectorsFormat(Optional.of(mapperService));
+
+        Function<PerFieldKnnVectorsFormat, Codec> knnCodecProvider = (knnVectorFormat) -> KNN950Codec.builder()
+            .delegate(V_9_5_0.getDefaultCodecDelegate())
+            .knnVectorsFormat(knnVectorFormat)
+            .build();
+
+        testKnnVectorIndex(knnCodecProvider, perFieldKnnVectorsFormatProvider);
+    }
+}

src/test/java/org/opensearch/knn/index/codec/KNNCodecFactoryTests.java

@@ -9,11 +9,13 @@
 import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.backward_codecs.lucene91.Lucene91Codec;
 import org.apache.lucene.backward_codecs.lucene94.Lucene94Codec;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.opensearch.knn.KNNTestCase;
 
 import static org.opensearch.knn.index.codec.KNNCodecVersion.V_9_1_0;
 import static org.opensearch.knn.index.codec.KNNCodecVersion.V_9_2_0;
 import static org.opensearch.knn.index.codec.KNNCodecVersion.V_9_4_0;
+import static org.opensearch.knn.index.codec.KNNCodecVersion.V_9_5_0;
 
 public class KNNCodecFactoryTests extends KNNTestCase {
 
@@ -35,6 +37,12 @@ public void testKNN940Codec() {
         assertNotNull(V_9_4_0.getKnnFormatFacadeSupplier().apply(V_9_4_0.getDefaultCodecDelegate()));
     }
 
+    public void testKNN950Codec() {
+        assertDelegateForVersion(V_9_5_0, Lucene95Codec.class);
+        assertNotNull(V_9_5_0.getPerFieldKnnVectorsFormat());
+        assertNotNull(V_9_5_0.getKnnFormatFacadeSupplier().apply(V_9_5_0.getDefaultCodecDelegate()));
+    }
+
     private void assertDelegateForVersion(final KNNCodecVersion codecVersion, final Class expectedCodecClass) {
         final Codec defaultDelegate = codecVersion.getDefaultCodecDelegate();
         assertNotNull(defaultDelegate);