lib: Add iterator over a tree node's children

refs #6630

library/Icinga/Data/Tree/TreeNodeIterator.php

@@ -0,0 +1,93 @@
+<?php
+/* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Data\Tree;
+
+use ArrayIterator;
+use RecursiveIterator;
+
+/**
+ * Iterator over a tree node's children
+ */
+class TreeNodeIterator implements RecursiveIterator
+{
+    /**
+     * The node's children
+     *
+     * @type array
+     */
+    protected $children;
+
+    /**
+     * Create a new iterator over a tree node's children
+     *
+     * @param Node $node
+     */
+    public function __construct(Node $node)
+    {
+        $this->children = new ArrayIterator($node->getChildren());
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::current() For the method documentation.
+     */
+    public function current()
+    {
+        return $this->children->current();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::key() For the method documentation.
+     */
+    public function key()
+    {
+        return $this->children->key();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::next() For the method documentation.
+     */
+    public function next()
+    {
+        $this->children->next();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::rewind() For the method documentation.
+     */
+    public function rewind()
+    {
+        $this->children->rewind();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::valid() For the method documentation.
+     */
+    public function valid()
+    {
+        return $this->children->valid();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::hasChildren() For the method documentation.
+     */
+    public function hasChildren()
+    {
+        return $this->current()->hasChildren();
+    }
+
+    /**
+     * (non-PHPDoc)
+     * @see \RecursiveIterator::getChildren() For the method documentation.
+     */
+    public function getChildren()
+    {
+        return new static($this->current());
+    }
+}