simple node builder added

src/Simple/NodeBuilder.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dakujem\Oliva\Simple;
+
+use Dakujem\Oliva\MovableNodeContract;
+use Dakujem\Oliva\TreeNodeContract;
+use LogicException;
+
+/**
+ * A trivial builder that ensures the children are bound to the respective parent.
+ *
+ * @author Andrej Rypak <[email protected]>
+ */
+class NodeBuilder
+{
+    /** @var callable */
+    private $factory;
+
+    public function __construct(
+        callable $node,
+    ) {
+        $this->factory = $node;
+    }
+
+    public function node(mixed $data, iterable $children = []): TreeNodeContract
+    {
+        // Build the node.
+        $node = ($this->factory)($data);
+
+        // Check for consistency.
+        if (!$node instanceof MovableNodeContract) {
+            // TODO improve exceptions
+            throw new LogicException('The node factory must return a movable node instance.');
+        }
+
+        // Bind the children.
+        foreach ($children as $key => $child) {
+            // Check for consistency.
+            if (!$child instanceof MovableNodeContract) {
+                // TODO improve exceptions
+                throw new LogicException('The children must be movable node instances.');
+            }
+            $child->setParent($node);
+            $node->addChild($child, $key);
+        }
+
+        return $node;
+    }
+}

src/Simple/TreeBuilder.php

@@ -10,7 +10,7 @@
 
 /**
  * Simple tree builder.
- * Wraps data that is already structured into tree node classes.
+ * Wraps data that is already structured as a tree into tree node classes.
  *
  * @author Andrej Rypak <[email protected]>
  */
@@ -21,14 +21,14 @@ public function build(
         callable $node,
         callable $children,
     ): TreeNodeContract {
-        return $this->buildNode(
+        return $this->wrapNode(
             data: $data,
             nodeFactory: $node,
             childrenExtractor: $children,
         );
     }
 
-    public function buildNode(
+    private function wrapNode(
         mixed $data,
         callable $nodeFactory,
         callable $childrenExtractor,
@@ -48,7 +48,7 @@ public function buildNode(
             throw new LogicException('Children data extractor must return an iterable collection containing children data.');
         }
         foreach ($childrenData ?? [] as $key => $childData) {
-            $child = $this->buildNode(
+            $child = $this->wrapNode(
                 data: $childData,
                 nodeFactory: $nodeFactory,
                 childrenExtractor: $childrenExtractor,