Added a simple system for treeViews.

src/Controller/TreeController.php

@@ -0,0 +1,74 @@
+<?php
+/**
+ * part-db version 0.1
+ * Copyright (C) 2005 Christoph Lechner
+ * http://www.cl-projects.de/.
+ *
+ * part-db version 0.2+
+ * Copyright (C) 2009 K. Jacobs and others (see authors.php)
+ * http://code.google.com/p/part-db/
+ *
+ * Part-DB Version 0.4+
+ * Copyright (C) 2016 - 2019 Jan Böhmer
+ * https://github.com/jbtronics
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+namespace App\Controller;
+
+use App\Entity\Category;
+use App\Helpers\TreeViewNode;
+use App\Services\ToolsTreeBuilder;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\Routing\Annotation\Route;
+
+/**
+ * This controller has the purpose to provide the data for all treeviews.
+ *
+ * @package App\Controller
+ */
+class TreeController extends AbstractController
+{
+    /**
+     * @Route("/tree/tools/", name="tree_tools")
+     */
+    public function tools(ToolsTreeBuilder $builder)
+    {
+        $tree = $builder->getTree();
+
+        //Ignore null values, to save data
+        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+    }
+
+    /**
+     * @Route("/tree/category/{id}", name="tree_category")
+     */
+    public function categoryTree(TreeBuilder $builder, Category $category = null)
+    {
+        if($category != null) {
+            $tree[] = $builder->elementToTreeNode($category);
+        } else {
+            $tree = $builder->typeToTree(Category::class);
+        }
+
+
+        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+    }
+
+
+
+
+}