Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/lib/Drupal/Component/Plugin/PluginManagerBase.php

@@ -0,0 +1,100 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Plugin\PluginManagerBase.
+ */
+
+namespace Drupal\Component\Plugin;
+
+use Drupal\Component\Plugin\Discovery\DiscoveryTrait;
+use Drupal\Component\Plugin\Exception\PluginNotFoundException;
+
+/**
+ * Base class for plugin managers.
+ */
+abstract class PluginManagerBase implements PluginManagerInterface {
+
+  use DiscoveryTrait;
+
+  /**
+   * The object that discovers plugins managed by this manager.
+   *
+   * @var \Drupal\Component\Plugin\Discovery\DiscoveryInterface
+   */
+  protected $discovery;
+
+  /**
+   * The object that instantiates plugins managed by this manager.
+   *
+   * @var \Drupal\Component\Plugin\Factory\FactoryInterface
+   */
+  protected $factory;
+
+  /**
+   * The object that returns the preconfigured plugin instance appropriate for a particular runtime condition.
+   *
+   * @var \Drupal\Component\Plugin\Mapper\MapperInterface
+   */
+  protected $mapper;
+
+  /**
+   * Gets the plugin discovery.
+   *
+   * @return \Drupal\Component\Plugin\Discovery\DiscoveryInterface
+   */
+  protected function getDiscovery() {
+    return $this->discovery;
+  }
+
+  /**
+   * Gets the plugin factory.
+   *
+   * @return \Drupal\Component\Plugin\Factory\FactoryInterface
+   */
+  protected function getFactory() {
+    return $this->factory;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefinition($plugin_id, $exception_on_invalid = TRUE) {
+    return $this->getDiscovery()->getDefinition($plugin_id, $exception_on_invalid);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefinitions() {
+    return $this->getDiscovery()->getDefinitions();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function createInstance($plugin_id, array $configuration = array()) {
+    // If this PluginManager has fallback capabilities catch
+    // PluginNotFoundExceptions.
+    if ($this instanceof FallbackPluginManagerInterface) {
+      try {
+        return $this->getFactory()->createInstance($plugin_id, $configuration);
+      }
+      catch (PluginNotFoundException $e) {
+        $fallback_id = $this->getFallbackPluginId($plugin_id, $configuration);
+        return $this->getFactory()->createInstance($fallback_id, $configuration);
+      }
+    }
+    else {
+      return $this->getFactory()->createInstance($plugin_id, $configuration);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInstance(array $options) {
+    return $this->mapper->getInstance($options);
+  }
+
+}