Add class MDFileIsNotWritable

exceptions/updates/MDFileIsNotWritable.php

@@ -0,0 +1,24 @@
+<?PHP
+/**
+ * This file contains an exception class for notifying about non-writable directories.
+ *
+ * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+ */
+declare(strict_types = 1);
+
+/**
+ * Custom exception class for throwing if a given file path is not writable.
+ */
+final class MDFileIsNotWritable extends Exception {
+    /**
+     * Error message.
+     *
+     * @return string
+     */
+    public function errorMessage() {
+        //error message
+        $errorMsg = 'This file or directory cannot be written: ' . $this->getMessage();
+        return $errorMsg;
+
+    }
+}