adressing comments and simplifying code

Author: normen662

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/AbstractNode.java

@@ -45,10 +45,6 @@ abstract class AbstractNode<N extends NodeReference> implements Node<N> {
 
     /**
      * Constructs a new {@code AbstractNode} with a specified primary key and a list of neighbors.
-     * <p>
-     * This constructor creates a defensive, immutable copy of the provided {@code neighbors} list.
-     * This ensures that the internal state of the node cannot be modified by external
-     * changes to the original list after construction.
      *
      * @param primaryKey the unique identifier for this node; must not be {@code null}
      * @param neighbors the list of nodes connected to this node; must not be {@code null}

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/AbstractStorageAdapter.java

@@ -36,7 +36,7 @@
 /**
  * An abstract base class for {@link StorageAdapter} implementations.
  * <p>
- * This class provides the common infrastructure for managing HNSW graph data within {@link Subspace}.
+ * This class provides the common infrastructure for managing HNSW graph data within a {@link Subspace}.
  * It handles the configuration, node creation, and listener management, while delegating the actual
  * storage-specific read and write operations to concrete subclasses through the {@code fetchNodeInternal}
  * and {@code writeNodeInternal} abstract methods.

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/AggregatedVector.java

@@ -21,9 +21,14 @@
 package com.apple.foundationdb.async.hnsw;
 
 import com.apple.foundationdb.linear.RealVector;
+import com.google.common.base.Objects;
 
 import javax.annotation.Nonnull;
 
+/**
+ * A record-like class wrapping a {@link RealVector} and a count. This data structure is used to keep a running sum
+ * of many vectors in order to compute their centroid at a later time.
+ */
 class AggregatedVector {
     private final int partialCount;
     @Nonnull
@@ -44,20 +49,17 @@ public RealVector getPartialVector() {
     }
 
     @Override
-    public final boolean equals(final Object o) {
+    public boolean equals(final Object o) {
         if (!(o instanceof AggregatedVector)) {
             return false;
         }
-
         final AggregatedVector that = (AggregatedVector)o;
-        return partialCount == that.partialCount && partialVector.equals(that.partialVector);
+        return partialCount == that.partialCount && Objects.equal(partialVector, that.partialVector);
     }
 
     @Override
     public int hashCode() {
-        int result = partialCount;
-        result = 31 * result + partialVector.hashCode();
-        return result;
+        return Objects.hashCode(partialCount, partialVector);
     }
 
     @Override

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/CompactStorageAdapter.java

@@ -57,9 +57,6 @@ class CompactStorageAdapter extends AbstractStorageAdapter<NodeReference> implem
 
     /**
      * Constructs a new {@code CompactStorageAdapter}.
-     * <p>
-     * This constructor initializes the adapter by delegating to the superclass,
-     * setting up the necessary components for managing an HNSW graph.
      *
      * @param config the HNSW graph configuration, must not be null. See {@link Config}.
      * @param nodeFactory the factory used to create new nodes of type {@link NodeReference}, must not be null.
@@ -223,7 +220,7 @@ private AbstractNode<NodeReference> compactNodeFromTuples(@Nonnull final AffineO
                                                               @Nonnull final Tuple vectorTuple,
                                                               @Nonnull final Tuple neighborsTuple) {
         final RealVector vector =
-                storageTransform.applyInvert(StorageAdapter.vectorFromTuple(getConfig(), vectorTuple));
+                storageTransform.invertedApply(StorageAdapter.vectorFromTuple(getConfig(), vectorTuple));
         final List<NodeReference> nodeReferences = Lists.newArrayListWithExpectedSize(neighborsTuple.size());
 
         for (int i = 0; i < neighborsTuple.size(); i ++) {

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/EntryNodeReference.java

@@ -77,9 +77,6 @@ public EntryNodeReference withVector(@Nonnull RealVector newVector) {
      */
     @Override
     public boolean equals(final Object o) {
-        if (!(o instanceof EntryNodeReference)) {
-            return false;
-        }
         if (!super.equals(o)) {
             return false;
         }

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/HNSW.java

@@ -276,7 +276,7 @@ private Quantizer quantizer(@Nullable final AccessInfo accessInfo) {
                     final EntryNodeReference entryNodeReference = accessInfo.getEntryNodeReference();
 
                     final AffineOperator storageTransform = storageTransform(accessInfo);
-                    final RealVector transformedQueryVector = storageTransform.applyInvert(queryVector);
+                    final RealVector transformedQueryVector = storageTransform.invertedApply(queryVector);
                     final Quantizer quantizer = quantizer(accessInfo);
                     final Estimator estimator = quantizer.estimator();
 
@@ -788,7 +788,7 @@ public CompletableFuture<Void> insert(@Nonnull final Transaction transaction, @N
                 .thenCompose(accessInfo -> {
                     final AccessInfo currentAccessInfo;
                     final AffineOperator storageTransform = storageTransform(accessInfo);
-                    final RealVector transformedNewVector = storageTransform.applyInvert(newVector);
+                    final RealVector transformedNewVector = storageTransform.invertedApply(newVector);
                     final Quantizer quantizer = quantizer(accessInfo);
                     final Estimator estimator = quantizer.estimator();
 
@@ -888,10 +888,10 @@ private CompletableFuture<Void> addToStats(@Nonnull final Transaction transactio
 
                                     final RealVector centroid =
                                             partialVector.multiply(1.0d / partialCount);
-                                    final RealVector transformedCentroid = rotator.applyInvert(centroid);
+                                    final RealVector transformedCentroid = rotator.invertedApply(centroid);
 
                                     final var transformedEntryNodeVector =
-                                            rotator.applyInvert(currentAccessInfo.getEntryNodeReference()
+                                            rotator.invertedApply(currentAccessInfo.getEntryNodeReference()
                                                     .getVector()).subtract(transformedCentroid);
 
                                     final AccessInfo newAccessInfo =
@@ -1547,34 +1547,4 @@ private boolean shouldMaintainStats(final int batchSize) {
         double pBatch = -Math.expm1(batchSize * Math.log1p(-getConfig().getMaintainStatsProbability()));
         return random.nextDouble() < pBatch;
     }
-
-    private static class NodeReferenceWithLayer extends NodeReferenceWithVector {
-        private final int layer;
-
-        public NodeReferenceWithLayer(@Nonnull final Tuple primaryKey, @Nonnull final RealVector vector,
-                                      final int layer) {
-            super(primaryKey, vector);
-            this.layer = layer;
-        }
-
-        public int getLayer() {
-            return layer;
-        }
-
-        @Override
-        public boolean equals(final Object o) {
-            if (!(o instanceof NodeReferenceWithLayer)) {
-                return false;
-            }
-            if (!super.equals(o)) {
-                return false;
-            }
-            return layer == ((NodeReferenceWithLayer)o).layer;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(super.hashCode(), layer);
-        }
-    }
 }

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/InliningStorageAdapter.java

@@ -212,7 +212,7 @@ private NodeReferenceWithVector neighborFromTuples(@Nonnull final AffineOperator
                                                        @Nonnull final Tuple keyTuple, @Nonnull final Tuple valueTuple) {
         final Tuple neighborPrimaryKey = keyTuple.getNestedTuple(2); // neighbor primary key
         final RealVector neighborVector =
-                storageTransform.applyInvert(
+                storageTransform.invertedApply(
                         StorageAdapter.vectorFromTuple(getConfig(), valueTuple)); // the entire value is the vector
         return new NodeReferenceWithVector(neighborPrimaryKey, neighborVector);
     }

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/NodeReference.java

@@ -78,7 +78,13 @@ public NodeReferenceWithVector asNodeReferenceWithVector() {
      */
     @Override
     public boolean equals(final Object o) {
-        if (!(o instanceof NodeReference)) {
+        if (o == null) {
+            return false;
+        }
+        if (this == o) {
+            return true;
+        }
+        if (o.getClass() != this.getClass()) {
             return false;
         }
         final NodeReference that = (NodeReference)o;

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/NodeReferenceWithDistance.java

@@ -72,9 +72,6 @@ public double getDistance() {
      */
     @Override
     public boolean equals(final Object o) {
-        if (!(o instanceof NodeReferenceWithDistance)) {
-            return false;
-        }
         if (!super.equals(o)) {
             return false;
         }

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/NodeReferenceWithVector.java

@@ -94,9 +94,6 @@ public NodeReferenceWithVector asNodeReferenceWithVector() {
      */
     @Override
     public boolean equals(final Object o) {
-        if (!(o instanceof NodeReferenceWithVector)) {
-            return false;
-        }
         if (!super.equals(o)) {
             return false;
         }