privatized Registry.scene and added listener.

src/main/java/com/marginallyclever/ro3/Registry.java

@@ -10,6 +10,8 @@
 import com.marginallyclever.ro3.render.renderpasses.DrawPoses;
 import com.marginallyclever.ro3.texture.TextureFactory;
 
+import javax.swing.event.EventListenerList;
+
 /**
  * {@link Registry} is a place to store global variables.
  */
@@ -18,8 +20,9 @@ public class Registry {
     public static final Factory<Node> nodeFactory = new Factory<>(Node.class);
     public static ListWithEvents<RenderPass> renderPasses = new ListWithEvents<>();
 
-    public static Node scene = new Node("Scene");
+    private static Node scene = new Node("Scene");
     public static ListWithEvents<Camera> cameras = new ListWithEvents<>();
+    public static EventListenerList listeners = new EventListenerList();
 
     public static void start() {
         Factory.Category<Node> nodule = new Factory.Category<>("Node", null);
@@ -38,4 +41,24 @@ public static void start() {
         renderPasses.add(new DrawPoses());
         renderPasses.add(new DrawCameras());
     }
+
+    public static void addSceneChangeListener(SceneChangeListener listener) {
+        listeners.add(SceneChangeListener.class,listener);
+    }
+
+    public static void removeSceneChangeListener(SceneChangeListener listener) {
+        listeners.remove(SceneChangeListener.class,listener);
+    }
+
+    public static void setScene(Node newScene) {
+        scene = newScene;
+
+        for (SceneChangeListener listener : listeners.getListeners(SceneChangeListener.class)) {
+            listener.afterSceneChange(newScene);
+        }
+    }
+
+    public static Node getScene() {
+        return scene;
+    }
 }

src/main/java/com/marginallyclever/ro3/SceneChangeListener.java

@@ -0,0 +1,10 @@
+package com.marginallyclever.ro3;
+
+import com.marginallyclever.ro3.node.Node;
+
+import java.util.EventListener;
+
+public interface SceneChangeListener extends EventListener {
+    void beforeSceneChange(Node oldScene);
+    void afterSceneChange(Node newScene);
+}

src/main/java/com/marginallyclever/ro3/actions/ImportScene.java

@@ -0,0 +1,62 @@
+package com.marginallyclever.ro3.actions;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.marginallyclever.ro3.Registry;
+import com.marginallyclever.ro3.node.Node;
+import com.marginallyclever.robotoverlord.RobotOverlord;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Load a Scene into the existing Scene.
+ */
+public class ImportScene extends AbstractAction {
+    private static final JFileChooser chooser = new JFileChooser();
+    private static final Logger logger = LoggerFactory.getLogger(ImportScene.class);
+
+    public ImportScene() {
+        super("Import Scene");
+    }
+
+    /**
+     * Invoked when an action occurs.
+     *
+     * @param e the event to be processed
+     */
+    @Override
+    public void actionPerformed(ActionEvent e) {
+        chooser.setFileFilter(RobotOverlord.FILE_FILTER);
+
+        Component source = (Component) e.getSource();
+        JFrame parentFrame = (JFrame)SwingUtilities.getWindowAncestor(source);
+        if (chooser.showOpenDialog(parentFrame) == JFileChooser.APPROVE_OPTION) {
+            loadIntoScene(chooser.getSelectedFile());
+        }
+    }
+
+    private void loadIntoScene(File selectedFile) {
+        logger.info("Import scene from {}",selectedFile.getAbsolutePath());
+
+        // Create an ObjectMapper instance
+        ObjectMapper mapper = new ObjectMapper();
+
+        try {
+            // Read the JSON file and convert it into a Node object
+            Node loaded = mapper.readValue(selectedFile, Node.class);
+
+            // option 1: add the loaded scene to the current scene.
+            Registry.getScene().addChild(loaded);
+            // TODO option 2: copy the loaded scene into the currently selected Nodes of the NodeTreeView?
+        } catch (IOException e) {
+            logger.error("Error loading scene from JSON", e);
+        }
+
+        logger.error("Import scene not implemented yet.");
+    }
+}

src/main/java/com/marginallyclever/ro3/actions/LoadScene.java

@@ -1,5 +1,8 @@
 package com.marginallyclever.ro3.actions;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.marginallyclever.ro3.Registry;
+import com.marginallyclever.ro3.node.Node;
 import com.marginallyclever.robotoverlord.RobotOverlord;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -8,6 +11,7 @@
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.io.File;
+import java.io.IOException;
 
 public class LoadScene extends AbstractAction {
     private static final JFileChooser chooser = new JFileChooser();
@@ -36,5 +40,18 @@ public void actionPerformed(ActionEvent e) {
     private void loadAsNewScene(File selectedFile) {
         logger.info("Load scene from {}",selectedFile.getAbsolutePath());
         logger.error("Load Scene not implemented yet.");
+
+        // Create an ObjectMapper instance
+        ObjectMapper mapper = new ObjectMapper();
+
+        try {
+            // Read the JSON file and convert it into a Node object
+            Node loaded = mapper.readValue(selectedFile, Node.class);
+            Registry.setScene(loaded);
+        } catch (IOException e) {
+            logger.error("Error loading scene from JSON", e);
+        }
+
+        logger.info("done.");
     }
 }

src/main/java/com/marginallyclever/ro3/actions/NewScene.java

@@ -1,10 +1,14 @@
 package com.marginallyclever.ro3.actions;
 
+import com.marginallyclever.ro3.Registry;
+import com.marginallyclever.ro3.node.Node;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import javax.swing.*;
 import java.awt.event.ActionEvent;
+import java.util.ArrayList;
+import java.util.List;
 
 public class NewScene extends AbstractAction {
     private static final Logger logger = LoggerFactory.getLogger(NewScene.class);
@@ -20,6 +24,17 @@ public NewScene() {
      */
     @Override
     public void actionPerformed(ActionEvent e) {
-        logger.error("New Scene not implemented yet.");
+        logger.info("New scene");
+
+        // remove all children of the scene to make sure we're starting fresh.
+        Node oldScene = Registry.getScene();
+        List<Node> children = new ArrayList<>(oldScene.getChildren());
+        for(Node child : children) {
+            oldScene.removeChild(child);
+        }
+        // remove the scene and replace it completely.
+        Registry.setScene(new Node("Scene"));
+
+        logger.info("done.");
     }
 }

src/main/java/com/marginallyclever/ro3/actions/SaveScene.java

@@ -1,5 +1,7 @@
 package com.marginallyclever.ro3.actions;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.marginallyclever.ro3.Registry;
 import com.marginallyclever.robotoverlord.RobotOverlord;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -8,6 +10,7 @@
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.io.File;
+import java.io.IOException;
 
 public class SaveScene extends AbstractAction {
     private static final JFileChooser chooser = new JFileChooser();
@@ -49,6 +52,17 @@ public void actionPerformed(ActionEvent e) {
 
     private void saveScene(String absolutePath) {
         logger.info("Save scene to {}",absolutePath);
-        logger.error("Save Scene not implemented yet.");
+
+        // Create an ObjectMapper instance
+        ObjectMapper mapper = new ObjectMapper();
+
+        try {
+            // Write the Registry.scene to a JSON file
+            mapper.writeValue(new File(absolutePath), Registry.getScene());
+        } catch (IOException e) {
+            logger.error("Error saving scene to JSON", e);
+        }
+
+        logger.info("done.");
     }
 }

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

@@ -1,7 +1,11 @@
 package com.marginallyclever.ro3.node;
 
+import com.marginallyclever.ro3.Registry;
 import com.marginallyclever.ro3.node.nodes.Pose;
 import com.marginallyclever.robotoverlord.swing.CollapsiblePanel;
+import org.json.JSONObject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -15,10 +19,11 @@
  * A node in a tree.
  */
 public class Node {
+    private static final Logger logger = LoggerFactory.getLogger(Node.class);
     private String name;
     private final List<Node> children = new ArrayList<>();
     private Node parent;
-    private final UUID nodeID;
+    private UUID nodeID;
     private final EventListenerList listeners = new EventListenerList();
 
     public Node() {
@@ -301,13 +306,26 @@ public boolean isNameUsedBySibling(String newName) {
         return false;
     }
 
+    /**
+     * A convenience method to add a label and component to a panel that is expected to be built with
+     * <code>new GridLayout(0, 2)</code>.
+     * @param pane the panel to add to
+     * @param labelText the text for the label
+     * @param component the component to add
+     */
     protected void addLabelAndComponent(JPanel pane, String labelText, JComponent component) {
         JLabel label = new JLabel(labelText);
         label.setLabelFor(component);
         pane.add(label);
         pane.add(component);
     }
 
+    /**
+     * Find the first child of the given type.
+     * @param type the type of node to find
+     * @return the first sibling of the given type, or null if none found.
+     * @param <T> the type of node to find
+     */
     public <T extends Node> T findFirstChild(Class<T> type) {
         for(Node child : children) {
             if(type.isInstance(child)) {
@@ -317,6 +335,12 @@ public <T extends Node> T findFirstChild(Class<T> type) {
         return null;
     }
 
+    /**
+     * Find the first sibling of the given type.
+     * @param type the type of node to find
+     * @return the first sibling of the given type, or null if none found.
+     * @param <T> the type of node to find
+     */
     public <T extends Node> T findFirstSibling(Class<T> type) {
         if(parent==null) return null;
         for(Node child : parent.children) {
@@ -326,4 +350,42 @@ public <T extends Node> T findFirstSibling(Class<T> type) {
         }
         return null;
     }
+
+    /**
+     * Serialize this node and its children to a JSON object and its children.
+     * Classes that override this method should call super.toJSON() first, then add to the object returned.
+     * @return the JSON object.
+     */
+    public JSONObject toJSON() {
+        logger.info("Saving node {}.",getAbsolutePath());
+        JSONObject json = new JSONObject();
+        json.put("type",getClass().getSimpleName());
+        json.put("name",name);
+        json.put("nodeID",nodeID.toString());
+        json.put("children",children);
+        return json;
+    }
+
+    /**
+     * Deserialize this node and its children from a JSON object and its children.
+     * Classes that override this method should call super.fromJSON().  When they do it will trigger the creation of
+     * child nodes.  The child nodes will then call their own fromJSON() methods.
+     * @param from the JSON object to read from.
+     */
+    public void fromJSON(JSONObject from) {
+        name = from.getString("name");
+        logger.info("Loading node {}.",name);
+        nodeID = UUID.fromString(from.getString("nodeID"));
+        children.clear();
+        for (Object o : from.getJSONArray("children")) {
+            JSONObject child = (JSONObject) o;
+            Node n = Registry.nodeFactory.create(child.getString("type"));
+            if(n==null) {
+                logger.error("{}: Could not create type {}.",getAbsolutePath(),child.getString("type"));
+                n = new Node();
+            }
+            n.fromJSON(child);
+            addChild(n);
+        }
+    }
 }