fix: remove TreeNodeUtils.addKeyAndGetIndex method

src/main/java/com/github/sepgh/internal/tree/BPlusTreeIndexManager.java

@@ -89,7 +89,12 @@ public BaseTreeNode addIndex(int table, long identifier, Pointer pointer) throws
                 InternalTreeNode currentInternalTreeNode = (InternalTreeNode) currentNode;
                 if (currentInternalTreeNode.getKeyList(degree).size() < degree - 1) {
                     /* current internal node can store the key */
-                    currentInternalTreeNode.addChildPointers(idForParentToStore, null, newChildForParent.getPointer(), degree, false);
+                    int indexOfAddedKey = currentInternalTreeNode.addKey(idForParentToStore, degree);
+                    if (newChildForParent.getKeyList(degree).getFirst() < idForParentToStore){
+                        currentInternalTreeNode.addChildAtIndex(indexOfAddedKey, newChildForParent.getPointer());
+                    } else {
+                        currentInternalTreeNode.addChildAtIndex(indexOfAddedKey + 1, newChildForParent.getPointer());
+                    }
                     TreeNodeIO.write(currentInternalTreeNode, indexStorageManager, table).get();
                     return answer;
                 }

src/main/java/com/github/sepgh/internal/tree/TreeNodeUtils.java

@@ -247,75 +247,6 @@ public static void removeKeyValueAtIndex(BaseTreeNode treeNode, int index) {
         }
     }
 
-    /**
-     * @param treeNode to read/write from/to
-     * @param key to add
-     * @return index which key is added to
-     * Todo: performance improvements may be possible
-     *       linear search is used to sort the keys
-     *       binary search could be used
-     *       alternatively, we can hold a space for metadata which keeps track of the number of keys or values stored
-     */
-    public static int addKeyAndGetIndex(BaseTreeNode treeNode, long key, int degree) {
-        // Shall only be called on internal nodes
-        if (treeNode.isLeaf()){
-            throw new RuntimeException();  // Todo: not runtime
-        }
-
-        int indexToFill = 0;
-        long keyAtIndex = 0;
-        for (int i = 0; i < degree - 1; i++){
-            keyAtIndex = getKeyAtIndex(treeNode, i);
-            if (keyAtIndex == 0 || keyAtIndex > key){
-                indexToFill = i;
-                break;
-            }
-        }
-
-        if (keyAtIndex == 0){
-            System.arraycopy(
-                    Longs.toByteArray(key),
-                    0,
-                    treeNode.getData(),
-                    OFFSET_INTERNAL_NODE_KEY_BEGIN + (indexToFill * (SIZE_INTERNAL_NODE_KEY_POINTER)),
-                    Long.BYTES
-            );
-            return indexToFill;
-        }
-
-
-        int max = degree - 1;
-        int fullSize = (max * SIZE_INTERNAL_NODE_KEY_POINTER) + OFFSET_INTERNAL_NODE_KEY_BEGIN;
-        int bufferSize = fullSize - ((indexToFill + 1) * SIZE_INTERNAL_NODE_KEY_POINTER) - OFFSET_INTERNAL_NODE_KEY_BEGIN;
-
-        byte[] temp = new byte[bufferSize];
-        System.arraycopy(
-                treeNode.getData(),
-                OFFSET_INTERNAL_NODE_KEY_BEGIN + (indexToFill * SIZE_INTERNAL_NODE_KEY_POINTER),
-                temp,
-                0,
-                temp.length
-        );
-
-        System.arraycopy(
-                Longs.toByteArray(key),
-                0,
-                treeNode.getData(),
-                OFFSET_INTERNAL_NODE_KEY_BEGIN + (indexToFill * SIZE_INTERNAL_NODE_KEY_POINTER),
-                Long.BYTES
-        );
-
-        System.arraycopy(
-                temp,
-                0,
-                treeNode.getData(),
-                OFFSET_INTERNAL_NODE_KEY_BEGIN + ((indexToFill + 1) * SIZE_INTERNAL_NODE_KEY_POINTER),
-                temp.length
-        );
-
-        return indexToFill;
-    }
-
     public static Optional<Pointer> getPreviousPointer(BaseTreeNode treeNode, int degree){
         if (treeNode.getData()[OFFSET_LEAF_NODE_KEY_BEGIN + ((degree - 1) * SIZE_LEAF_NODE_KEY_POINTER)] == (byte) 0x0){
             return Optional.empty();

src/main/java/com/github/sepgh/internal/tree/node/InternalTreeNode.java

@@ -61,8 +61,7 @@ public int addKey(long identifier, int degree) {
 
     public void addChildPointers(long identifier, @Nullable Pointer left, @Nullable Pointer right, int degree, boolean clearForNull){
         modified();
-        // Todo: since we spotted an issue with (addKeyAndGetIndex), using this.addKey() should be feasible but using it would break some test cases and needs investigation to see if test is wrong or the implementation is wrong
-        int i = TreeNodeUtils.addKeyAndGetIndex(this, identifier, degree);
+        int i = this.addKey(identifier, degree);
         if (left != null){
             TreeNodeUtils.setPointerToChild(this, i, left);
         }
@@ -92,6 +91,16 @@ public List<Pointer> getChildrenList(){
         return ImmutableList.copyOf(getChildren());
     }
 
+    public void addChildAtIndex(int index, Pointer pointer){
+        List<Pointer> childrenList = new ArrayList<>(this.getChildrenList());
+        childrenList.add(index, pointer);
+
+        for (int i = index; i < childrenList.size(); i++){
+            this.setChildAtIndex(i, childrenList.get(i));
+        }
+
+    }
+
     public void setChildAtIndex(int index, Pointer pointer){
         TreeNodeUtils.setPointerToChild(this, index, pointer);
     }

src/test/java/com/github/sepgh/internal/helper/IndexFileDescriptor.java

@@ -88,6 +88,8 @@ private void printLeafNode(LeafTreeNode node, int offset){
         }
         System.out.println("Key Values:");
         System.out.println(stringBuilder);
+        System.out.println("Prev: " + node.getPreviousSiblingPointer(engineConfig.getBTreeNodeMaxKey() + 1));
+        System.out.println("Next: " + node.getNextSiblingPointer(engineConfig.getBTreeNodeMaxKey() + 1));
         System.out.println("===========================");
     }
 

src/test/java/com/github/sepgh/internal/tree/storing/MultiTableBPlusTreeIndexManagerTestCase.java

@@ -1,6 +1,7 @@
 package com.github.sepgh.internal.tree.storing;
 
 import com.github.sepgh.internal.EngineConfig;
+import com.github.sepgh.internal.helper.IndexFileDescriptor;
 import com.github.sepgh.internal.storage.FileIndexStorageManager;
 import com.github.sepgh.internal.storage.InMemoryHeaderManager;
 import com.github.sepgh.internal.storage.header.Header;
@@ -16,6 +17,7 @@
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
+import java.nio.channels.AsynchronousFileChannel;
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
@@ -190,16 +192,28 @@ public void testMultiSplitAddIndex2() throws IOException, ExecutionException, In
 
         List<Long> testIdentifiers = Arrays.asList(1L, 4L, 9L, 6L, 10L, 8L, 3L, 2L, 11L, 5L, 7L, 12L);
         Pointer samplePointer = new Pointer(Pointer.TYPE_DATA, 100, 0);
+        HeaderManager headerManager = new InMemoryHeaderManager(header);
+        FileIndexStorageManager fileIndexStorageManager = new FileIndexStorageManager(dbPath, headerManager, engineConfig);
+        IndexManager indexManager = new BPlusTreeIndexManager(degree, fileIndexStorageManager);
+
+        IndexFileDescriptor indexFileDescriptor = new IndexFileDescriptor(
+                AsynchronousFileChannel.open(
+                        Path.of(dbPath.toString(), String.format("%s.%d", INDEX_FILE_NAME, 0)),
+                        StandardOpenOption.READ,
+                        StandardOpenOption.WRITE,
+                        StandardOpenOption.CREATE
+                ),
+                headerManager,
+                engineConfig
+        );
 
         for (int tableId = 1; tableId <= 2; tableId++){
-            HeaderManager headerManager = new InMemoryHeaderManager(header);
-            FileIndexStorageManager fileIndexStorageManager = new FileIndexStorageManager(dbPath, headerManager, engineConfig);
-            IndexManager indexManager = new BPlusTreeIndexManager(degree, fileIndexStorageManager);
-
 
             BaseTreeNode lastTreeNode = null;
             for (long testIdentifier : testIdentifiers) {
                 lastTreeNode = indexManager.addIndex(tableId, testIdentifier, samplePointer);
+                System.out.println("Adding " + testIdentifier + " to table " + tableId);
+                indexFileDescriptor.describe();
             }
 
             Assertions.assertTrue(lastTreeNode.isLeaf());

src/test/java/com/github/sepgh/internal/tree/storing/StoredTreeStructureVerifier.java

@@ -64,7 +64,7 @@ public static void testUnOrderedTreeStructure1(IndexStorageManager indexStorageM
         // 2nd Leaf
         Optional<Pointer> nextPointer = currentLeaf.getNextSiblingPointer(degree);
         Assertions.assertTrue(nextPointer.isPresent());
-        Assertions.assertEquals(nextPointer.get(), leftChildInternalNode.getChildPointersList(degree).get(0).getRight());
+        Assertions.assertEquals(nextPointer.get(), leftChildInternalNode.getChildAtIndex(1));
 
         currentLeaf = (LeafTreeNode) TreeNodeIO.read(indexStorageManager, table, leftChildInternalNode.getChildPointersList(degree).get(0).getRight());
         currentLeafKeys = currentLeaf.getKeyList(degree);