--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Config\Definition\Builder;
+
+/**
+ * This class builds merge conditions.
+ *
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+class MergeBuilder
+{
+ protected $node;
+ public $allowFalse = false;
+ public $allowOverwrite = true;
+
+ /**
+ * Constructor.
+ *
+ * @param NodeDefinition $node The related node
+ */
+ public function __construct(NodeDefinition $node)
+ {
+ $this->node = $node;
+ }
+
+ /**
+ * Sets whether the node can be unset.
+ *
+ * @param bool $allow
+ *
+ * @return $this
+ */
+ public function allowUnset($allow = true)
+ {
+ $this->allowFalse = $allow;
+
+ return $this;
+ }
+
+ /**
+ * Sets whether the node can be overwritten.
+ *
+ * @param bool $deny Whether the overwriting is forbidden or not
+ *
+ * @return $this
+ */
+ public function denyOverwrite($deny = true)
+ {
+ $this->allowOverwrite = !$deny;
+
+ return $this;
+ }
+
+ /**
+ * Returns the related node.
+ *
+ * @return NodeDefinition|ArrayNodeDefinition|VariableNodeDefinition
+ */
+ public function end()
+ {
+ return $this->node;
+ }
+}