Unify Function and Rerank

Signed-off-by: yhmo <yihua.mo@zilliz.com>

Author: yhmo

examples/src/main/java/io/milvus/v2/HybridSearchExample.java

@@ -213,7 +213,7 @@ private void hybridSearch() {
         HybridSearchReq hybridSearchReq = HybridSearchReq.builder()
                 .collectionName(COLLECTION_NAME)
                 .searchRequests(searchRequests)
-                .ranker(new WeightedRanker(Arrays.asList(0.2f, 0.5f, 0.6f)))
+                .ranker(WeightedRanker.builder().weights(Arrays.asList(0.2f, 0.5f, 0.6f)).build())
                 .limit(5)
                 .consistencyLevel(ConsistencyLevel.BOUNDED)
                 .build();

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/BaseRanker.java

@@ -19,8 +19,18 @@
 
 package io.milvus.v2.service.vector.request.ranker;
 
-import java.util.Map;
+import io.milvus.common.clientenum.FunctionType;
+import io.milvus.v2.service.collection.request.CreateCollectionReq;
+import lombok.experimental.SuperBuilder;
 
-public abstract class BaseRanker {
-    public abstract Map<String, String> getProperties();
+// In v2.6, the Function and Rerank have been unified to support more rerank types: decay and model ranker
+// https://milvus.io/docs/decay-ranker-overview.md
+// https://milvus.io/docs/model-ranker-overview.md
+// So we have to inherit the BaseRanker from Function, this change will lead to uncomfortable issues with
+// RRFRanker/WeightedRanker in some users client code. We will mention it in release note.
+@SuperBuilder
+public class BaseRanker extends CreateCollectionReq.Function {
+    public FunctionType getFunctionType() {
+        return FunctionType.RERANK;
+    }
 }

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/RRFRanker.java

@@ -20,22 +20,21 @@
 package io.milvus.v2.service.vector.request.ranker;
 
 import com.google.gson.JsonObject;
+import lombok.Builder;
+import lombok.experimental.SuperBuilder;
 
 import java.util.HashMap;
 import java.util.Map;
 
 /**
  * The RRF reranking strategy, which merges results from multiple searches, favoring items that consistently appear.
  */
+@SuperBuilder
 public class RRFRanker extends BaseRanker {
+    @Builder.Default
     private int k = 60;
 
-    public RRFRanker(int k) {
-        this.k = k;
-    }
-
-    @Override
-    public Map<String, String> getProperties() {
+    public Map<String, String> getParams() {
         JsonObject params = new JsonObject();
         params.addProperty("k", this.k);
 

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/WeightedRanker.java

@@ -21,7 +21,10 @@
 
 import com.google.gson.JsonObject;
 import io.milvus.common.utils.JsonUtils;
+import lombok.Builder;
+import lombok.experimental.SuperBuilder;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -30,15 +33,12 @@
  * The Average Weighted Scoring reranking strategy, which prioritizes vectors based on relevance,
  * averaging their significance.
  */
+@SuperBuilder
 public class WeightedRanker extends BaseRanker {
-    private List<Float> weights;
+    @Builder.Default
+    private List<Float> weights = new ArrayList<>();
 
-    public WeightedRanker(List<Float> weights) {
-        this.weights = weights;
-    }
-
-    @Override
-    public Map<String, String> getProperties() {
+    public Map<String, String> getParams() {
         JsonObject params = new JsonObject();
         params.add("weights", JsonUtils.toJsonTree(this.weights).getAsJsonArray());
 

sdk-core/src/main/java/io/milvus/v2/utils/VectorUtils.java

@@ -479,7 +479,7 @@ public HybridSearchRequest ConvertToGrpcHybridSearchRequest(HybridSearchReq requ
         }
 
         // topK value is deprecated, always use "limit" to set the topK
-        Map<String, String> props = ranker.getProperties();
+        Map<String, String> props = ranker.getParams();
         props.put(Constant.LIMIT, String.valueOf(request.getLimit()));
         props.put(Constant.ROUND_DECIMAL, String.valueOf(request.getRoundDecimal()));
         props.put(Constant.OFFSET, String.valueOf(request.getOffset()));

sdk-core/src/test/java/io/milvus/v2/client/MilvusClientV2DockerTest.java

@@ -1047,7 +1047,7 @@ void testHybridSearch() {
                     return HybridSearchReq.builder()
                             .collectionName(randomCollectionName)
                             .searchRequests(searchRequests)
-                            .ranker(new RRFRanker(20))
+                            .ranker(RRFRanker.builder().k(20).build())
                             .limit(topk)
                             .consistencyLevel(ConsistencyLevel.BOUNDED)
                             .build();
@@ -2853,7 +2853,7 @@ void testConsistencyLevel() throws InterruptedException {
                                     .databaseName(dbName)
                                     .collectionName(randomCollectionName)
                                     .searchRequests(Collections.singletonList(subReq))
-                                    .ranker(new RRFRanker(20))
+                                    .ranker(RRFRanker.builder().k(20).build())
                                     .limit(5)
                                     .build());
                             List<List<SearchResp.SearchResult>> oneResult = searchResp.getSearchResults();