Addressing comments

Signed-off-by: Bharathwaj G <[email protected]>

server/src/main/java/org/opensearch/index/codec/CodecService.java

@@ -39,7 +39,7 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.codec.composite.Composite99Codec;
+import org.opensearch.index.codec.composite.CompositeCodecFactory;
 import org.opensearch.index.mapper.MapperService;
 
 import java.util.Map;
@@ -78,10 +78,8 @@ public CodecService(@Nullable MapperService mapperService, IndexSettings indexSe
             // We can still support all the compression codecs when composite index is present
             // hence we're defining the codecs like below
             if (mapperService.isCompositeIndexPresent()) {
-                codecs.put(DEFAULT_CODEC, new Composite99Codec(Mode.BEST_SPEED, mapperService, logger));
-                codecs.put(LZ4, new Composite99Codec(Mode.BEST_SPEED, mapperService, logger));
-                codecs.put(BEST_COMPRESSION_CODEC, new Composite99Codec(Mode.BEST_COMPRESSION, mapperService, logger));
-                codecs.put(ZLIB, new Composite99Codec(Mode.BEST_COMPRESSION, mapperService, logger));
+                CompositeCodecFactory compositeCodecFactory = new CompositeCodecFactory();
+                codecs.putAll(compositeCodecFactory.getCompositeCodecs(mapperService, logger));
             } else {
                 codecs.put(DEFAULT_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
                 codecs.put(LZ4, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));

server/src/main/java/org/opensearch/index/codec/composite/Composite90DocValuesFormat.java

@@ -59,6 +59,6 @@ public DocValuesConsumer fieldsConsumer(SegmentWriteState state) throws IOExcept
 
     @Override
     public DocValuesProducer fieldsProducer(SegmentReadState state) throws IOException {
-        return new Composite90DocValuesReader(delegate.fieldsProducer(state), state, mapperService);
+        return new Composite90DocValuesReader(delegate.fieldsProducer(state), state);
     }
 }

server/src/main/java/org/opensearch/index/codec/composite/Composite90DocValuesReader.java

@@ -32,13 +32,9 @@
 @ExperimentalApi
 public class Composite90DocValuesReader extends DocValuesProducer implements CompositeIndexReader {
     private DocValuesProducer delegate;
-    Set<CompositeMappedFieldType> compositeMappedFieldTypes;
-    MapperService mapperService;
 
-    public Composite90DocValuesReader(DocValuesProducer producer, SegmentReadState state, MapperService mapperService) throws IOException {
+    public Composite90DocValuesReader(DocValuesProducer producer, SegmentReadState state) throws IOException {
         this.delegate = producer;
-        this.mapperService = mapperService;
-        this.compositeMappedFieldTypes = mapperService.getCompositeFieldTypes();
         // TODO : read star tree files
     }
 
@@ -82,13 +78,14 @@ public void close() throws IOException {
     @Override
     public List<String> getCompositeIndexFields() {
         // todo : read from file formats and get the field names.
-        return null;
+        throw new UnsupportedOperationException();
+
     }
 
     @Override
     public CompositeIndexValues getCompositeIndexValues(String field, CompositeMappedFieldType.CompositeFieldType fieldType)
         throws IOException {
         // TODO : read compositeIndexValues [starTreeValues] from star tree files
-        return null;
+        throw new UnsupportedOperationException();
     }
 }

server/src/main/java/org/opensearch/index/codec/composite/CompositeCodecFactory.java

@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.codec.composite;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.lucene99.Lucene99Codec;
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.index.mapper.MapperService;
+
+import static org.opensearch.index.codec.CodecService.BEST_COMPRESSION_CODEC;
+import static org.opensearch.index.codec.CodecService.DEFAULT_CODEC;
+import static org.opensearch.index.codec.CodecService.LZ4;
+import static org.opensearch.index.codec.CodecService.ZLIB;
+
+
+/**
+ * Factory class to return the latest composite codec for all the modes
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public class CompositeCodecFactory {
+    public CompositeCodecFactory() {}
+
+    public Map<String,Codec> getCompositeCodecs(MapperService mapperService, Logger logger) {
+        Map<String, Codec> codecs = new HashMap<>();
+        codecs.put(DEFAULT_CODEC, new Composite99Codec(Lucene99Codec.Mode.BEST_SPEED, mapperService, logger));
+        codecs.put(LZ4,  new Composite99Codec(Lucene99Codec.Mode.BEST_SPEED, mapperService, logger));
+        codecs.put(BEST_COMPRESSION_CODEC,  new Composite99Codec(Lucene99Codec.Mode.BEST_COMPRESSION, mapperService, logger));
+        codecs.put(ZLIB, new Composite99Codec(Lucene99Codec.Mode.BEST_COMPRESSION, mapperService, logger));
+        return codecs;
+    }
+}

server/src/main/java/org/opensearch/index/codec/composite/CompositeIndexValues.java

@@ -11,11 +11,11 @@
 import org.opensearch.common.annotation.ExperimentalApi;
 
 /**
- * Abstract class for composite index values
+ * Interface for composite index values
  *
  * @opensearch.experimental
  */
 @ExperimentalApi
-public abstract class CompositeIndexValues {
-    public abstract CompositeIndexValues getValues();
+public interface CompositeIndexValues {
+     CompositeIndexValues getValues();
 }

server/src/main/java/org/opensearch/index/codec/composite/datacube/startree/StarTreeValues.java

@@ -19,7 +19,7 @@
  * @opensearch.experimental
  */
 @ExperimentalApi
-public class StarTreeValues extends CompositeIndexValues {
+public class StarTreeValues implements CompositeIndexValues {
     private final List<String> dimensionsOrder;
 
     // TODO : come up with full set of vales such as dimensions and metrics doc values + star tree