Add new exception MDOutputBufferNotStarted

exceptions/generic/MDOutputBufferNotStarted.php

@@ -0,0 +1,28 @@
+<?PHP
+/**
+ * This file contains an exception class for trying to enter non-existent files.
+ *
+ * @file
+ *
+ * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+ */
+declare(strict_types = 1);
+
+/**
+ * Custom exception class for non-existing files.
+ */
+class MDOutputBufferNotStarted extends Exception {
+
+    /**
+     * Error message.
+     *
+     * @return string
+     */
+    public function errorMessage() {
+        //error message
+        $errorMsg = 'Output buffer has not yet been started, is to be used: ' . $this->getMessage();
+        return $errorMsg;
+
+    }
+
+}