Minor cleanup

Signed-off-by: John Mazanec <[email protected]>

CHANGELOG.md

@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add binary index support for Lucene engine. (#2292)[https://github.com/opensearch-project/k-NN/pull/2292]
 - Add expand_nested_docs Parameter support to NMSLIB engine (#2331)[https://github.com/opensearch-project/k-NN/pull/2331]
 - Add cosine similarity support for faiss engine (#2376)[https://github.com/opensearch-project/k-NN/pull/2376]
+- Add derived source feature for vector fields (#2449)[https://github.com/opensearch-project/k-NN/pull/2449]
 ### Enhancements
 - Introduced a writing layer in native engines where relies on the writing interface to process IO. (#2241)[https://github.com/opensearch-project/k-NN/pull/2241]
 - Allow method parameter override for training based indices (#2290) https://github.com/opensearch-project/k-NN/pull/2290]

src/main/java/org/opensearch/knn/index/codec/derivedsource/NestedPerFieldDerivedVectorInjector.java

@@ -5,6 +5,7 @@
 
 package org.opensearch.knn.index.codec.derivedsource;
 
+import lombok.AllArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.PostingsEnum;
@@ -26,22 +27,13 @@
 import static org.apache.lucene.search.DocIdSetIterator.NO_MORE_DOCS;
 
 @Log4j2
+@AllArgsConstructor
 public class NestedPerFieldDerivedVectorInjector implements PerFieldDerivedVectorInjector {
 
     private final FieldInfo childFieldInfo;
     private final DerivedSourceReaders derivedSourceReaders;
     private final SegmentReadState segmentReadState;
 
-    public NestedPerFieldDerivedVectorInjector(
-        FieldInfo childFieldInfo,
-        DerivedSourceReaders derivedSourceReaders,
-        SegmentReadState segmentReadState
-    ) {
-        this.childFieldInfo = childFieldInfo;
-        this.derivedSourceReaders = derivedSourceReaders;
-        this.segmentReadState = segmentReadState;
-    }
-
     @Override
     public void inject(Integer parentDocId, Map<String, Object> sourceAsMap) throws IOException {
         // Setup the iterator. Return if not-relevant

src/main/java/org/opensearch/knn/index/codec/derivedsource/NestedPerFieldParentToDocIdIterator.java

@@ -68,15 +68,6 @@ public int firstChild() {
         return previousParentDocId + 1;
     }
 
-    /**
-     * Get the number of children for this parent.
-     *
-     * @return number of children for this parent
-     */
-    public int numChildren() {
-        return children.size();
-    }
-
     /**
      * Get the next child for this parent
      *