Manage the expanded state of the tree items

src/main/java/fr/ill/ics/n3d/Nomad3DEditor.java

 package fr.ill.ics.n3d;
 
 import java.io.File;
+import java.util.HashMap;
 import java.util.Optional;
 import java.util.logging.FileHandler;
 import java.util.logging.Level;
@@ -36,10 +37,11 @@ import javafx.scene.Scene;
 import javafx.scene.SceneAntialiasing;
 import javafx.scene.SubScene;
 import javafx.scene.control.Alert;
+import javafx.scene.control.Alert.AlertType;
 import javafx.scene.control.ButtonType;
 import javafx.scene.control.MenuBar;
+import javafx.scene.control.TreeItem;
 import javafx.scene.control.TreeView;
-import javafx.scene.control.Alert.AlertType;
 import javafx.scene.input.KeyCode;
 import javafx.scene.layout.BorderPane;
 import javafx.scene.layout.StackPane;
@@ -379,6 +381,7 @@ public class Nomad3DEditor extends Application {
 		buildCamera();
 			
 		TreeView<Component> hierarchyView = buildHierarchyView();
+		
 
 		this.pane = new BorderPane();
         pane.setTop(buildMenuBar());
@@ -415,10 +418,20 @@ public class Nomad3DEditor extends Application {
 	
 	/**
 	 * Builds the hierarchy view.
-	 * @return The trre view.
+	 * @return The tree view.
 	 */
 	private TreeView<Component> buildHierarchyView() {
-		TreeView<Component> hierarchyView = (model != null && model.getRoot() != null) ? new TreeView<Component>(model.getRoot().getTreeItem()) : new TreeView<Component>();
+		
+		TreeView<Component> hierarchyView = null;
+		
+		if ((model != null && model.getRoot() != null)) {
+			hierarchyView = new TreeView<Component>(model.getRoot().getTreeItem());
+			expandTreeView(model.getRoot().getTreeItem());
+		}
+		else {
+			hierarchyView = new TreeView<Component>();			
+		}
+				
 		hierarchyView.setEditable(true);
 		hierarchyView.setMinWidth(100);
 		hierarchyView.setPrefWidth(300);
@@ -584,4 +597,73 @@ public class Nomad3DEditor extends Application {
 			}
 		});
 	}
+	
+	/**
+	 * Expands all the tree item hierarchy.
+	 * @param item The item to begin.
+	 */
+	public void expandTreeView(TreeItem<Component> item) {
+		
+	    if (item != null && !item.isLeaf()) {
+	        item.setExpanded(true);
+	        for (TreeItem<Component> child : item.getChildren()) {
+	            expandTreeView(child);
+	        }
+	    }
+	}
+	
+	/**
+	 * Gets the current expanded state of the tree item hierarchy.
+	 * @param item The item to begin.
+	 * @param states The map to save the states.
+	 */
+	private void getTreeViewExpandedStates(TreeItem<Component> item, HashMap<String, Boolean> states) {
+		
+		if (item != null && !item.isLeaf()) {
+	        
+			states.put(item.getValue().getName(), item.expandedProperty().getValue());
+			
+	        for (TreeItem<Component> child : item.getChildren()) {
+	        	getTreeViewExpandedStates(child, states);
+	        }
+	    }
+	}
+
+	/**
+	 * Gets the current expanded state of the tree item hierarchy.
+	 * @param item The item to begin.
+	 * @return The map of the states.
+	 */
+	public HashMap<String, Boolean> getTreeViewExpandedStates(TreeItem<Component> item) {
+
+		HashMap<String, Boolean> states = new HashMap<>();
+		
+		getTreeViewExpandedStates(item, states);
+		
+		return states;
+	}
+	
+	/**
+	 * Expands all the tree item hierarchy following the initial states map.
+	 * @param item The item to begin.
+	 * @param states The map of the states.
+	 */
+	public void expandTreeView(TreeItem<Component> item, HashMap<String, Boolean> states) {
+		
+	    if (item != null && !item.isLeaf()) {
+	        
+	    	String componentName = item.getValue().getName();
+	    	
+	    	if (states.containsKey(componentName)) {
+	    		item.setExpanded(states.get(componentName));
+	    	}
+	    	else {
+	    		item.setExpanded(true);
+	    	}
+	        
+	        for (TreeItem<Component> child : item.getChildren()) {
+	            expandTreeView(child, states);
+	        }
+	    }
+	}
 }

src/main/java/fr/ill/ics/n3d/gui/EditorMenuBar.java

@@ -5,6 +5,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.text.DecimalFormat;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.Optional;
@@ -702,8 +703,6 @@ public class EditorMenuBar extends MenuBar {
 				
 				// Do not save the operation if the axis is the same.
 				if (!selectedAxis.equals(initialAxis)) {
-				
-					System.out.println("Axis modified");
 
 					// Stop the build.
 					Nomad3DEditor.getInstance().getAxisBuilder().stop(selectedComponent);
@@ -745,9 +744,6 @@ public class EditorMenuBar extends MenuBar {
 					// Change the title.
 					updateModified(true);
 				}
-				else {
-					System.out.println("Axis NOT modified");
-				}
 				
 				Nomad3DEditor.getInstance().getModel().clearSelection();
 				updateScene();
@@ -2415,12 +2411,19 @@ public class EditorMenuBar extends MenuBar {
 		if (!modelLoaded()) {
 			return;
 		}
+		
+		// Save the expanded state of the tree items.
+		HashMap<String, Boolean> itemStates = Nomad3DEditor.getInstance().getTreeViewExpandedStates(Nomad3DEditor.getInstance().getModel().getRoot().getTreeItem());
+		
 		Nomad3DEditor.getInstance().getModel().clearSelection();
 		Nomad3DEditor.getInstance().getRoot().getChildren().remove(Nomad3DEditor.getInstance().getModel().getRoot().getSceneNode());
 		Nomad3DEditor.getInstance().getModel().computeSceneHierarchies(activeLod);
 		Nomad3DEditor.getInstance().getRoot().getChildren().add(Nomad3DEditor.getInstance().getModel().getRoot().getSceneNode());
 		((TreeView<Component>) Nomad3DEditor.getInstance().getPane().getLeft()).setRoot(Nomad3DEditor.getInstance().getModel().getRoot().getTreeItem());
 
+		// Restore the expanded state of the tree items.
+		Nomad3DEditor.getInstance().expandTreeView(Nomad3DEditor.getInstance().getModel().getRoot().getTreeItem(), itemStates);
+		
 		updateAxes();
 		updateWalls();
 		updateSystem();