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lib/pkp/classes/core/PKPServices.php

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+<?php
+
+/**
+ * @file classes/core/PKPServices.php
+ *
+ * Copyright (c) 2014-2021 Simon Fraser University
+ * Copyright (c) 2000-2021 John Willinsky
+ * Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
+ *
+ * @class PKPServices
+ *
+ * @ingroup core
+ *
+ * @see Core
+ *
+ * @brief Pimple Dependency Injection Container.
+ */
+
+namespace PKP\core;
+
+use APP\core\Services;
+use Pimple\Container;
+
+abstract class PKPServices
+{
+    /** @var Container Pimple Dependency Injection Container */
+    private static $instance = null;
+
+    protected $container = null;
+
+    /**
+     * private constructor
+     */
+    private function __construct()
+    {
+        $this->container = new Container();
+        $this->init();
+    }
+
+    /**
+     * container initialization
+     */
+    abstract protected function init();
+
+    /**
+     * A static method to register a service
+     */
+    public static function register(\Pimple\ServiceProviderInterface $service)
+    {
+        self::_instance()->container->register($service);
+    }
+
+    /**
+     * A static method to get a service
+     *
+     * @param string $service
+     */
+    public static function get($service)
+    {
+        return self::_instance()->_getFromContainer($service);
+    }
+
+    /**
+     * Returns the instance of the container
+     *
+     * @return static
+     */
+    private static function _instance()
+    {
+        if (is_null(self::$instance)) {
+            self::$instance = new Services();
+        }
+
+        return self::$instance;
+    }
+
+    /**
+     * Gets the service from an instanced container.
+     *
+     * @param string $service
+     */
+    private function _getFromContainer($service)
+    {
+        return $this->container[$service];
+    }
+}
+
+if (!PKP_STRICT_MODE) {
+    class_alias('\PKP\core\PKPServices', '\PKPServices');
+}