improved NodeTreeView sorting

src/main/java/com/marginallyclever/ro3/node/Node.java

@@ -37,19 +37,32 @@ public Node(String name) {
         this.name = name;
     }
 
+    /**
+     * Append a child to this node.
+     * @param child the child to add.
+     */
     public void addChild(Node child) {
-        children.add(child);
+        addChild(children.size(),child);
+    }
+
+    /**
+     * Add a child to this node at the given index.
+     * @param index the index to add the child at.
+     * @param child the child to add.
+     */
+    public void addChild(int index,Node child) {
+        if(index<0|| index>children.size()) {
+            throw new IndexOutOfBoundsException("Index "+index+" is out of bounds.");
+        }
+
+        children.add(index,child);
         child.setParent(this);
         fireAttachEvent(child);
         child.onAttach();
         if(child.children.isEmpty()) {
             fireReadyEvent(child);
             child.onReady();
-        }/* else {
-            for(Node grandchild : child.children) {
-                child.addChild(grandchild);
-            }
-        }*/
+        }
     }
 
     private void fireReadyEvent(Node child) {

src/main/java/com/marginallyclever/ro3/node/nodetreeview/NodeTreeTransferHandler.java

@@ -1,11 +1,14 @@
 package com.marginallyclever.ro3.node.nodetreeview;
 import com.marginallyclever.ro3.node.Node;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import javax.swing.*;
 import javax.swing.tree.*;
 import java.awt.datatransfer.*;
 
 public class NodeTreeTransferHandler extends TransferHandler {
+    private static final Logger logger = LoggerFactory.getLogger(NodeTreeTransferHandler.class);
     @Override
     public int getSourceActions(JComponent c) {
         return MOVE;
@@ -41,26 +44,46 @@ public boolean importData(TransferHandler.TransferSupport support) {
         }
 
         JTree tree = (JTree) support.getComponent();
-        DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
         JTree.DropLocation dl = (JTree.DropLocation) support.getDropLocation();
         TreePath destPath = dl.getPath();
-        Node newParent = ((NodeTreeBranch) destPath.getLastPathComponent()).getNode();
+        NodeTreeBranch newParentBranch = (NodeTreeBranch) destPath.getLastPathComponent();
+        Node newParent = newParentBranch.getNode();
 
         try {
             Transferable transferable = support.getTransferable();
-            Node sourceNode = (Node) transferable.getTransferData(NodeTransferable.nodeFlavor);
+            Node beingMoved = (Node) transferable.getTransferData(NodeTransferable.nodeFlavor);
+
+            // Prevent a node from being dragged to itself
+            if (beingMoved == newParent) {
+                return false;
+            }
 
             // Remove node from its current parent
-            Node oldParent = sourceNode.getParent();
+            Node oldParent = beingMoved.getParent();
+            int oldIndex = -1;
             if (oldParent != null) {
-                oldParent.removeChild(sourceNode);
+                oldIndex = oldParent.getChildren().indexOf(beingMoved);
+                oldParent.removeChild(beingMoved);
+                logger.debug("oldIndex: {}", oldIndex);
             }
 
-            // Add node to the new parent
-            newParent.addChild(sourceNode);
+            // Get the index at which the source node will be added
+            int newIndex = dl.getChildIndex();
+            logger.debug("newIndex: {}", newIndex);
+            if (newIndex == -1) {
+                // If the drop location is a node, add the node at the end
+                newParent.addChild(beingMoved);
+            } else {
+                // If oldParent and newParent are the same instance, adjust the index accordingly
+                if (oldParent == newParent && oldIndex < newIndex) {
+                    newIndex--;
+                }
+                // If the drop location is an index, add the node at the specified index
+                newParent.addChild(newIndex, beingMoved);
+            }
             return true;
         } catch (Exception e) {
-            e.printStackTrace();
+            logger.error("importData", e);
         }
         return false;
     }

src/main/java/com/marginallyclever/ro3/node/nodetreeview/NodeTreeView.java

@@ -1,7 +1,5 @@
 package com.marginallyclever.ro3.node.nodetreeview;
 
-import com.marginallyclever.ro3.DockingPanel;
-import com.marginallyclever.ro3.FactoryPanel;
 import com.marginallyclever.ro3.Registry;
 import com.marginallyclever.ro3.SceneChangeListener;
 import com.marginallyclever.ro3.actions.AddNode;
@@ -17,7 +15,6 @@
 import javax.swing.event.EventListenerList;
 import javax.swing.tree.*;
 import java.awt.*;
-import java.awt.event.ActionEvent;
 import java.security.InvalidParameterException;
 import java.util.*;
 import java.util.List;
@@ -105,7 +102,7 @@ public void scanTree(Node toScan) {
 
         NodeTreeBranch parentBranch = findTreeNode(toScan);
         if(parentBranch == null) {
-            logger.error("node has no branch");
+            logger.error("Node has no branch");
             return;
         }
 
@@ -160,42 +157,48 @@ private void fireSelectionChangeEvent(List<Node> newSelection) {
     }
 
     @Override
-    public void nodeAttached(Node source) {
-        logger.debug("attached "+source.getAbsolutePath());
-        Node parent = source.getParent();
+    public void nodeAttached(Node child) {
+        logger.debug("Attached "+child.getAbsolutePath());
+        Node parent = child.getParent();
         if(parent==null) throw new RuntimeException("source node has no parent");
         NodeTreeBranch branchParent = findTreeNode(parent);
         if(branchParent==null) throw new RuntimeException("parent node has no branch");
-        NodeTreeBranch branchChild = new NodeTreeBranch(source);
-        branchParent.add(branchChild);
+        NodeTreeBranch branchChild = new NodeTreeBranch(child);
+        int index = parent.getChildren().indexOf(child);
+        branchParent.insert(branchChild,index);
 
-        source.addAttachListener(this);
-        source.addDetachListener(this);
-        source.addRenameListener(this);
+        child.addAttachListener(this);
+        child.addDetachListener(this);
+        child.addRenameListener(this);
 
-        scanTree(source);
+        scanTree(child);
 
         ((DefaultTreeModel) tree.getModel()).nodeStructureChanged(branchParent);
     }
 
     @Override
-    public void nodeDetached(Node source) {
-        logger.debug("detached "+source.getAbsolutePath());
-        source.removeAttachListener(this);
-        source.removeDetachListener(this);
-        source.removeRenameListener(this);
-
-        Node parent = source.getParent();
-        if(parent==null) throw new RuntimeException("source node has no parent");
+    public void nodeDetached(Node child) {
+        logger.debug("Detached "+child.getAbsolutePath());
+        child.removeAttachListener(this);
+        child.removeDetachListener(this);
+        child.removeRenameListener(this);
+
+        Node parent = child.getParent();
+        if(parent==null) throw new RuntimeException("Source node has no parent");
         NodeTreeBranch branchParent = findTreeNode(parent);
-        if(branchParent==null) throw new RuntimeException("parent node has no branch");
-        branchParent.remove(findTreeNode(source));
+        if(branchParent==null) throw new RuntimeException("Parent node has no branch");
+        NodeTreeBranch branchChild = findTreeNode(child);
+        if(branchChild==null) {
+            logger.warn("No branch for "+child.getAbsolutePath());
+            return;
+        }
+        branchParent.remove(branchChild);
         ((DefaultTreeModel) tree.getModel()).nodeStructureChanged(branchParent);
     }
 
     @Override
     public void nodeRenamed(Node source) {
-        logger.debug("renamed "+source.getAbsolutePath());
+        logger.debug("Renamed "+source.getAbsolutePath());
         NodeTreeBranch branch = findTreeNode(source);
         if (branch != null) {
             ((DefaultTreeModel) tree.getModel()).nodeChanged(branch);