diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/AggregatorPluginSettingsBase.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/AggregatorPluginSettingsBase.php
index a89a641..55013e1 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/AggregatorPluginSettingsBase.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/AggregatorPluginSettingsBase.php
@@ -7,13 +7,14 @@
 
 namespace Drupal\aggregator\Plugin;
 
+use Drupal\Component\Plugin\ConfigurablePluginInterface;
 use Drupal\Component\Plugin\PluginBase;
 use Drupal\Core\Plugin\PluginFormInterface;
 
 /**
  * Base class for aggregator plugins that implement settings forms.
  */
-abstract class AggregatorPluginSettingsBase extends PluginBase implements PluginFormInterface {
+abstract class AggregatorPluginSettingsBase extends PluginBase implements PluginFormInterface, ConfigurablePluginInterface {
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/aggregator/processor/DefaultProcessor.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/aggregator/processor/DefaultProcessor.php
index b44a448..3f27ecd 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/aggregator/processor/DefaultProcessor.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/aggregator/processor/DefaultProcessor.php
@@ -50,8 +50,8 @@ class DefaultProcessor extends AggregatorPluginSettingsBase implements Processor
    *   The configuration factory object.
    */
   public function __construct(array $configuration, $plugin_id, array $plugin_definition, ConfigFactory $config) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->configFactory = $config;
+    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition);
   }
 
   /**
@@ -65,8 +65,7 @@ public static function create(ContainerInterface $container, array $configuratio
    * {@inheritdoc}
    */
   public function buildConfigurationForm(array $form, array &$form_state) {
-    $config = $this->configFactory->get('aggregator.settings');
-    $processors = $config->get('processors');
+    $processors = $this->configuration['processors'];
     $info = $this->getPluginDefinition();
     $items = drupal_map_assoc(array(3, 5, 10, 15, 20, 25), array($this, 'formatItems'));
     $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200, 4838400, 9676800), 'format_interval');
@@ -86,7 +85,7 @@ public function buildConfigurationForm(array $form, array &$form_state) {
     $form['processors'][$info['id']]['aggregator_summary_items'] = array(
       '#type' => 'select',
       '#title' => t('Number of items shown in listing pages'),
-      '#default_value' => $config->get('source.list_max'),
+      '#default_value' => $this->configuration['source']['list_max'],
       '#empty_value' => 0,
       '#options' => $items,
     );
@@ -94,7 +93,7 @@ public function buildConfigurationForm(array $form, array &$form_state) {
     $form['processors'][$info['id']]['aggregator_clear'] = array(
       '#type' => 'select',
       '#title' => t('Discard items older than'),
-      '#default_value' => $config->get('items.expire'),
+      '#default_value' => $this->configuration['items']['expire'],
       '#options' => $period,
       '#description' => t('Requires a correctly configured <a href="@cron">cron maintenance task</a>.', array('@cron' => url('admin/reports/status'))),
     );
@@ -102,7 +101,7 @@ public function buildConfigurationForm(array $form, array &$form_state) {
     $form['processors'][$info['id']]['aggregator_category_selector'] = array(
       '#type' => 'radios',
       '#title' => t('Select categories using'),
-      '#default_value' => $config->get('source.category_selector'),
+      '#default_value' => $this->configuration['source']['category_selector'],
       '#options' => array('checkboxes' => t('checkboxes'),
       'select' => t('multiple selector')),
       '#description' => t('For a small number of categories, checkboxes are easier to use, while a multiple selector works well with large numbers of categories.'),
@@ -110,7 +109,7 @@ public function buildConfigurationForm(array $form, array &$form_state) {
     $form['processors'][$info['id']]['aggregator_teaser_length'] = array(
       '#type' => 'select',
       '#title' => t('Length of trimmed description'),
-      '#default_value' => $config->get('items.teaser_length'),
+      '#default_value' => $this->configuration['items']['teaser_length'],
       '#options' => drupal_map_assoc(array(0, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000), array($this, 'formatCharacters')),
       '#description' => t('The maximum number of characters used in the trimmed version of content.'),
     );
@@ -121,12 +120,11 @@ public function buildConfigurationForm(array $form, array &$form_state) {
    * {@inheritdoc}
    */
   public function submitConfigurationForm(array &$form, array &$form_state) {
-    $config = $this->configFactory->get('aggregator.settings');
-    $config->set('items.expire', $form_state['values']['aggregator_clear'])
-      ->set('items.teaser_length', $form_state['values']['aggregator_teaser_length'])
-      ->set('source.list_max', $form_state['values']['aggregator_summary_items'])
-      ->set('source.category_selector', $form_state['values']['aggregator_category_selector'])
-      ->save();
+    $this->configuration['items']['expire'] = $form_state['values']['aggregator_clear'];
+    $this->configuration['items']['teaser_length'] = $form_state['values']['aggregator_teaser_length'];
+    $this->configuration['source']['list_max'] = $form_state['values']['aggregator_summary_items'];
+    $this->configuration['source']['category_selector'] = $form_state['values']['aggregator_category_selector'];
+    $this->setConfiguration($this->configuration);
   }
 
   /**
@@ -198,7 +196,7 @@ public function remove(Feed $feed) {
    * Expires items from a feed depending on expiration settings.
    */
   public function postProcess(Feed $feed) {
-    $aggregator_clear = $this->configFactory->get('aggregator.settings')->get('items.expire');
+    $aggregator_clear = $this->configuration['items']['expire'];
 
     if ($aggregator_clear != AGGREGATOR_CLEAR_NEVER) {
       // Remove all items that are older than flush item timer.
@@ -215,6 +213,24 @@ public function postProcess(Feed $feed) {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function getConfiguration() {
+    return $this->configFactory->get('aggregator.settings')->get();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setConfiguration(array $configuration) {
+    $config = $this->configFactory->get('aggregator.settings');
+    foreach ($configuration as $key => $value) {
+      $config->set($key, $value);
+    }
+    $config->save();
+  }
+
+  /**
    * Helper function for drupal_map_assoc.
    *
    * @param int $count
diff --git a/core/modules/aggregator/tests/modules/aggregator_test/lib/Drupal/aggregator_test/Plugin/aggregator/processor/TestProcessor.php b/core/modules/aggregator/tests/modules/aggregator_test/lib/Drupal/aggregator_test/Plugin/aggregator/processor/TestProcessor.php
index afeda55..a0ba7f2 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test/lib/Drupal/aggregator_test/Plugin/aggregator/processor/TestProcessor.php
+++ b/core/modules/aggregator/tests/modules/aggregator_test/lib/Drupal/aggregator_test/Plugin/aggregator/processor/TestProcessor.php
@@ -56,8 +56,8 @@ public static function create(ContainerInterface $container, array $configuratio
    *   The configuration factory object.
    */
   public function __construct(array $configuration, $plugin_id, array $plugin_definition, ConfigFactory $config) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->configFactory = $config;
+    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition);
   }
 
   /**
@@ -79,7 +79,7 @@ public function buildConfigurationForm(array $form, array &$form_state) {
       '#type' => 'number',
       '#min' => 1,
       '#max' => 1000,
-      '#default_value' => $this->configFactory->get('aggregator_test.settings')->get('items.dummy_length'),
+      '#default_value' => $this->configuration['items']['dummy_length'],
     );
     return $form;
   }
@@ -88,9 +88,8 @@ public function buildConfigurationForm(array $form, array &$form_state) {
    * {@inheritdoc}
    */
   public function submitConfigurationForm(array &$form, array &$form_state) {
-    $this->configFactory->get('aggregator_test.settings')
-      ->set('items.dummy_length', $form_state['values']['dummy_length'])
-      ->save();
+    $this->configuration['items']['dummy_length'] = $form_state['values']['dummy_length'];
+    $this->setConfiguration($this->configuration);
   }
 
   /**
@@ -120,4 +119,22 @@ public function postProcess(Feed $feed) {
     $feed->save();
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getConfiguration() {
+    return $this->configFactory->get('aggregator_test.settings')->get();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setConfiguration(array $configuration) {
+    $config = $this->configFactory->get('aggregator_test.settings');
+    foreach ($configuration as $key => $value) {
+      $config->set($key, $value);
+    }
+    $config->save();
+  }
+
 }