first commit

modules/x13import/tools/Spout/Common/Singleton.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Box\Spout\Common;
+
+/**
+ * Class Singleton
+ * Defines a class as a singleton.
+ *
+ * @package Box\Spout\Common
+ */
+trait Singleton
+{
+    protected static $instance;
+
+    /**
+     * @return static
+     */
+    final public static function getInstance()
+    {
+        return isset(static::$instance)
+            ? static::$instance
+            : static::$instance = new static;
+    }
+
+    /**
+     * Singleton constructor.
+     */
+    final private function __construct()
+    {
+        $this->init();
+    }
+
+    /**
+     * Initializes the singleton
+     * @return void
+     */
+    protected function init() {}
+
+    final private function __wakeup() {}
+    final private function __clone() {}
+}