added basic invoice rendering #97 #93 (#99)

src/Invoice/NumberGeneratorInterface.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the Kimai package.
+ *
+ * (c) Kevin Papst <kevin@kevinpapst.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Invoice;
+
+use App\Model\InvoiceModel;
+
+/**
+ * Class NumberGeneratorInterface defines all methods that invoice number generator have to implement.
+ *
+ * @author Kevin Papst <kevin@kevinpapst.de>
+ */
+interface NumberGeneratorInterface
+{
+
+    /**
+     * @param InvoiceModel $model
+     */
+    public function setModel(InvoiceModel $model);
+
+    /**
+     * @return string
+     */
+    public function getInvoiceNumber(): string;
+}