Issue #2216539 by jhodgdon, dawehner: Fill in @defgroup/topic docs for Views overview.

core/modules/system/core.api.php

@@ -440,23 +440,6 @@
  * @}
  */
 
-/**
- * @defgroup views_overview Views overview
- * @{
- * Overview of the Views module API
- *
- * @todo write this
- *
- * Additional documentation paragraphs need to be written, and functions,
- * classes, and interfaces need to be added to this topic. Should link to all
- * or most of the existing Views topics, and maybe this should be moved into
- * a different file? This topic should be an overview so that developers know
- * which of the many Views classes and topics are important if they want to
- * accomplish tasks that they may have.
- * @}
- */
-
-
 /**
  * @defgroup i18n Internationalization
  * @{

core/modules/views/includes/ajax.inc

@@ -9,12 +9,6 @@ use Drupal\views\Ajax\HighlightCommand;
 use Drupal\Core\Ajax\OpenModalDialogCommand;
 use Drupal\Core\Ajax\AjaxResponse;
 
-/**
- * @defgroup views_ajax Views AJAX library
- * @{
- * Handles the server side AJAX interactions of Views.
- */
-
 /**
  * Wrapper around drupal_build_form to handle some AJAX stuff automatically.
  * This makes some assumptions about the client.
@@ -67,7 +61,3 @@ function views_ajax_form_wrapper($form_id, &$form_state) {
 
   return (!empty($form_state['title'])) ? array('#title' => $form_state['title'], '#markup' => $output) : $output;
 }
-
-/**
- * @}
- */

core/modules/views/src/Annotation/ViewsAccess.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views access plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\access\AccessPluginBase
+ *
+ * @ingroup views_access_plugins
+ *
+ * @Annotation
  */
 class ViewsAccess extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsArea.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views area handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\area\AreaPluginBase
+ *
+ * @ingroup views_area_handlers
+ *
+ * @Annotation
  */
 class ViewsArea extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsArgument.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views argument handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\argument\ArgumentPluginBase
+ *
+ * @ingroup views_argument_handlers
+ *
+ * @Annotation
  */
 class ViewsArgument extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsArgumentDefault.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views argument default plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase
+ *
+ * @ingroup views_argument_default_plugins
+ *
+ * @Annotation
  */
 class ViewsArgumentDefault extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsArgumentValidator.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views argument default plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase
+ *
+ * @ingroup views_argument_validate_plugins
+ *
+ * @Annotation
  */
 class ViewsArgumentValidator extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsCache.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views cache plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\cache\CachePluginBase
+ *
+ * @ingroup views_cache_plugins
+ *
+ * @Annotation
  */
 class ViewsCache extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsDisplay.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views display plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\display\DisplayPluginBase
+ *
+ * @ingroup views_display_plugins
+ *
+ * @Annotation
  */
 class ViewsDisplay extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsDisplayExtender.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views display extender plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase
+ *
+ * @ingroup views_display_extender_plugins
+ *
+ * @Annotation
  */
 class ViewsDisplayExtender extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsExposedForm.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views exposed form plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginBase
+ *
+ * @ingroup views_exposed_form_plugins
+ *
+ * @Annotation
  */
 class ViewsExposedForm extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsField.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views field handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\field\FieldPluginBase
+ *
+ * @ingroup views_field_handlers
+ *
+ * @Annotation
  */
 class ViewsField extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsFilter.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views filter handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\filter\FilterPluginBase
+ *
+ * @ingroup views_filter_handlers
+ *
+ * @Annotation
  */
 class ViewsFilter extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsJoin.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views join plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\join\JoinPluginBase
+ *
+ * @ingroup views_join_handlers
+ *
+ * @Annotation
  */
 class ViewsJoin extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsPager.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views pager plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\pager\PagerPluginBase
+ *
+ * @ingroup views_pager_plugins
+ *
+ * @Annotation
  */
 class ViewsPager extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsQuery.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views query plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\query\QueryPluginBase
+ *
+ * @ingroup views_query_plugins
+ *
+ * @Annotation
  */
 class ViewsQuery extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsRelationship.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views relationship handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\relationship\RelationshipPluginBase
+ *
+ * @ingroup views_relationship_handlers
+ *
+ * @Annotation
  */
 class ViewsRelationship extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsRow.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views row plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\row\RowPluginBase
+ *
+ * @ingroup views_row_plugins
+ *
+ * @Annotation
  */
 class ViewsRow extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsSort.php

@@ -10,9 +10,11 @@ namespace Drupal\views\Annotation;
 /**
  * Defines a Plugin annotation object for views sort handlers.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\sort\SortPluginBase
+ *
+ * @ingroup views_sort_handlers
+ *
+ * @Annotation
  */
 class ViewsSort extends ViewsHandlerAnnotationBase {
 

core/modules/views/src/Annotation/ViewsStyle.php

@@ -12,9 +12,11 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views style plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\style\StylePluginBase
+ *
+ * @ingroup views_style_plugins
+ *
+ * @Annotation
  */
 class ViewsStyle extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Annotation/ViewsWizard.php

@@ -12,9 +12,12 @@ use Drupal\views\Annotation\ViewsPluginAnnotationBase;
 /**
  * Defines a Plugin annotation object for views wizard plugins.
  *
- * @Annotation
- *
  * @see \Drupal\views\Plugin\views\wizard\WizardPluginBase
+ * @see \Drupal\views\Plugin\views\wizard\WizardInterface
+ *
+ * @ingroup views_wizard_plugins
+ *
+ * @Annotation
  */
 class ViewsWizard extends ViewsPluginAnnotationBase {
 

core/modules/views/src/Plugin/ViewsPluginManager.php

@@ -14,6 +14,8 @@ use Symfony\Component\DependencyInjection\Container;
 
 /**
  * Plugin type manager for all views plugins.
+ *
+ * @ingroup views_plugins
  */
 class ViewsPluginManager extends DefaultPluginManager {
 

core/modules/views/src/Plugin/views/HandlerBase.php

@@ -21,6 +21,11 @@ use Drupal\Core\Database\Database;
 use Drupal\views\Views;
 use Drupal\views\ViewsData;
 
+/**
+ * Base class for Views handler plugins.
+ *
+ * @ingroup views_plugins
+ */
 abstract class HandlerBase extends PluginBase {
 
   /**

core/modules/views/src/Plugin/views/PluginBase.php

@@ -37,6 +37,8 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *   root directory.
  * - module: machine name of the module. It must be present for any plugin that
  *   wants to register a theme.
+ *
+ * @ingroup views_plugins
  */
 abstract class PluginBase extends ComponentPluginBase implements ContainerFactoryPluginInterface {
 

core/modules/views/src/Plugin/views/access/AccessPluginBase.php

@@ -14,10 +14,17 @@ use Symfony\Component\Routing\Route;
 /**
  * @defgroup views_access_plugins Views access plugins
  * @{
- * The base plugin to handle access to a view.
+ * Plugins to handle access checking for views.
  *
- * Therefore it primarily has to implement the access and the alterRouteDefinition
+ * Access plugins are responsible for controlling access to the view.
- * method.
+ *
+ * Access plugins extend \Drupal\views\Plugin\views\access\AccessPluginBase,
+ * implementing the access() and alterRouteDefinition() methods. They must be
+ * annotated with \Drupal\views\Annotation\ViewsAccess annotation, and they
+ * must be in namespace directory Plugin\views\access.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/area/AreaPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\area\AreaPluginBase.
+ * Contains \Drupal\views\Plugin\views\area\AreaPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\area;
@@ -12,16 +12,20 @@ use Drupal\views\Plugin\views\display\DisplayPluginBase;
 use Drupal\views\Plugin\views\HandlerBase;
 
 /**
- * @defgroup views_area_handlers Views area handlers
+ * @defgroup views_area_handlers Views area handler plugins
  * @{
- * Handlers to tell Views what can display in header, footer
+ * Plugins governing areas of views, such as header, footer, and empty text.
- * and empty text in a view.
+ *
+ * Area handler plugins extend \Drupal\views\Plugin\views\area\AreaHandlerBase.
+ * They must be annotated with \Drupal\views\Annotation\ViewsArea annotation,
+ * and they must be in namespace directory Plugin\views\area.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
- * Base class for area handlers.
+ * Base class for area handler plugins.
- *
- * @ingroup views_area_handlers
  */
 abstract class AreaPluginBase extends HandlerBase {
 

core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php

@@ -17,12 +17,23 @@ use Drupal\views\Views;
 
 /**
  * @defgroup views_argument_handlers Views argument handlers
- * Handlers to tell Views how to contextually filter queries.
  * @{
+ * Handler plugins for Views contextual filters.
+ *
+ * Handler plugins help build the view query object. Views argument handlers
+ * are for contextual filtering.
+ *
+ * Views argument handlers extend
+ * \Drupal\views\Plugin\views\argument\ArgumentHandlerBase. They must be
+ * annotated with \Drupal\views\Annotation\ViewsArgument annotation, and they
+ * must be in namespace directory Plugin\views\argument.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
- * Base class for arguments.
+ * Base class for argument (contextual filter) handler plugins.
  *
  * The basic argument works for very simple arguments such as nid and uid
  *
@@ -42,8 +53,6 @@ use Drupal\views\Views;
  *                  and may disappear or change.
  * - numeric: If set to TRUE this field is numeric and will use %d instead of
  *            %s in queries.
- *
- * @ingroup views_argument_handlers
  */
 abstract class ArgumentPluginBase extends HandlerBase {
 

core/modules/views/src/Plugin/views/argument_default/ArgumentDefaultPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase.
+ * Contains \Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\argument_default;
@@ -14,7 +14,20 @@ use Drupal\views\Plugin\views\PluginBase;
 /**
  * @defgroup views_argument_default_plugins Views argument default plugins
  * @{
- * Allow specialized methods of filling in arguments when they aren't provided.
+ * Plugins for argument defaults in Views.
+ *
+ * Argument default plugins provide default values for contextual filters.
+ * This is useful for blocks and other display types lacking a natural argument
+ * input. Examples are plugins to extract node and user IDs from the URL.
+ *
+ * Argument default plugins extend
+ * \Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase. They
+ * must be annotated with \Drupal\Views\Annotation\ViewsArgumentDefault
+ * annotation, and they must be in namespace directory
+ * Plugin\views\argument_default.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase.
+ * Contains \Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\argument_validator;
@@ -14,7 +14,23 @@ use Drupal\views\Plugin\views\PluginBase;
 /**
  * @defgroup views_argument_validate_plugins Views argument validate plugins
  * @{
- * Allow specialized methods of validating arguments.
+ * Plugins for validating views contextual filters.
+ *
+ * Views argument validator plugins validate contextual filters (arguments) on
+ * views. They can ensure arguments are valid, and even do transformations on
+ * the arguments. They can also provide replacement patterns for the view title.
+ * For example, the 'content' validator verifies verifies that the argument
+ * value corresponds to a node, loads that node, and provides the node title
+ * as a replacement pattern for the view title.
+ *
+ * Argument validator plugins extend
+ * \Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase.
+ * They must be annotated with
+ * \Drupal\views\Plugin\Annotation\ViewsArgumentValidator annotation, and they
+ * must be in namespace directory Plugin\views\argument_validator.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/cache/CachePluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\cache\CachePluginBase.
+ * Contains \Drupal\views\Plugin\views\cache\CachePluginBase.
  */
 
 namespace Drupal\views\Plugin\views\cache;
@@ -14,10 +14,17 @@ use Drupal\Core\Database\Query\Select;
 /**
  * @defgroup views_cache_plugins Views cache plugins
  * @{
- * The base plugin to handler caching of a view.
+ * Plugins to handle the storage and loading of Views caches.
  *
- * Cache plugins can handle both caching of just the database result and
+ * Cache plugins control the storage and loading of caches in Views, for
- * the rendered output of the view.
+ * both result and render caching.
+ *
+ * Cache plugins extend \Drupal\views\Plugin\views\cache\CachePluginBase.
+ * They must be annotated with \Drupal\views\Annotation\ViewsCache
+ * annotation, and must be in namespace directory Plugin\views\cache.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/display/DisplayPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains Drupal\views\Plugin\views\display\DisplayPluginBase.
+ * Contains \Drupal\views\Plugin\views\display\DisplayPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\display;
@@ -22,16 +22,26 @@ use Symfony\Component\DependencyInjection\Exception\RuntimeException as Dependen
 /**
  * @defgroup views_display_plugins Views display plugins
  * @{
- * Display plugins control how Views interact with the rest of Drupal.
+ * Plugins to handle the overall display of views.
  *
- * They can handle creating Views from a Drupal page hook; they can
+ * Display plugins are responsible for controlling where a view is rendered;
- * handle creating Views from a Drupal block hook. They can also
+ * that is, how it is exposed to other parts of Drupal. 'Page' and 'block' are
- * handle creating Views from an external module source.
+ * the most commonly used display plugins. Each view also has a 'master' (or
+ * 'default') display that includes information shared between all its
+ * displays (see \Drupal\views\Plugin\views\display\DefaultDisplay).
+ *
+ * Display plugins extend \Drupal\views\Plugin\views\display\DisplayPluginBase.
+ * They must be annotated with \Drupal\views\Plugin\Annotation\ViewsDisplay
+ * annotation, and they must be in namespace directory Plugin\views\display.
+ *
+ * @ingroup views_plugins
+ *
+ * @see plugin_api
+ * @see views_display_extender_plugins
  */
 
 /**
- * The default display plugin handler. Display plugins handle options and
+ * Base class for views display plugins.
- * basic mechanisms for different output methods.
  */
 abstract class DisplayPluginBase extends PluginBase {
 

core/modules/views/src/Plugin/views/display_extender/DefaultDisplayExtender.php

@@ -2,13 +2,15 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\display_extender\DefaultDisplayExtender.
+ * Contains \Drupal\views\Plugin\views\display_extender\DefaultDisplayExtender.
  */
 
 namespace Drupal\views\Plugin\views\display_extender;
 
 /**
- * @todo
+ * Default display extender plugin; does nothing.
+ *
+ * @ingroup views_display_extender_plugins
  *
  * @ViewsDisplayExtender(
  *   id = "default",

core/modules/views/src/Plugin/views/display_extender/DisplayExtenderPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase.
+ * Contains \Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\display_extender;
@@ -11,9 +11,30 @@ use Drupal\views\ViewExecutable;
 use Drupal\views\Plugin\views\PluginBase;
 
 /**
- * @todo.
+ * @defgroup views_display_extender_plugins Views display extender plugins
+ * @{
+ * Plugins that offer additional display options across display types.
  *
- * @ingroup views_display_plugins
+ * Display extender plugins allow additional options or configuration to be
+ * added to views across all display types. For example, if you wanted to allow
+ * site users to add certain metadata to the rendered output of every view
+ * display regardless of display type, you could provide this option as a
+ * display extender.
+ *
+ * Display extender plugins extend
+ * \Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase.
+ * They must be annotated with
+ * \Drupal\views\Plugin\Annotation\ViewsDisplayExtender annotation, and they
+ * must be in namespace directory Plugin\views\display_extender.
+ *
+ * @ingroup views_plugins
+ *
+ * @see plugin_api
+ * @see views_display_plugins
+ */
+
+/**
+ * Base class for Views display extender plugins.
  */
 abstract class DisplayExtenderPluginBase extends PluginBase {
 
@@ -61,3 +82,7 @@ abstract class DisplayExtenderPluginBase extends PluginBase {
   public function defaultableSections(&$sections, $section = NULL) { }
 
 }
+
+/**
+ * @}
+ */

core/modules/views/src/Plugin/views/exposed_form/ExposedFormPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\exposed_form\ExposedFormPluginBase.
+ * Contains \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\exposed_form;
@@ -16,13 +16,21 @@ use Drupal\views\Plugin\views\PluginBase;
 /**
  * @defgroup views_exposed_form_plugins Views exposed form plugins
  * @{
- * Plugins that handle the validation/submission and rendering of exposed forms.
+ * Plugins that handle validation, submission, and rendering of exposed forms.
  *
- * If needed, it is possible to use them to add additional form elements.
+ * Exposed forms are used for filters, sorts, and pager settings that are
+ * exposed to site visitors. Exposed form plugins handle the rendering,
+ * validation, and submission of exposed forms, and may add additional form
+ * elements.
+ *
+ * Exposed form plugins extend
+ * \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginBase. They must be
+ * annotated with \Drupal\views\Plugin\Annotation\ViewsExposedForm annotation,
+ * and they must be in namespace directory Plugin\views\exposed_form.
  */
 
 /**
- * The base plugin to handle exposed filter forms.
+ * Base class for Views exposed filter form plugins.
  */
 abstract class ExposedFormPluginBase extends PluginBase {
 

core/modules/views/src/Plugin/views/field/FieldPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\field\FieldPluginBase.
+ * Contains \Drupal\views\Plugin\views\field\FieldPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\field;
@@ -17,24 +17,33 @@ use Drupal\views\ResultRow;
 use Drupal\views\ViewExecutable;
 
 /**
- * @defgroup views_field_handlers Views field handlers
+ * @defgroup views_field_handlers Views field handler plugins
  * @{
- * Handlers to tell Views how to build and display fields.
+ * Handler plugins for Views fields.
  *
+ * Field handlers handle both querying and display of fields in views.
+ *
+ * Field handler plugins extend
+ * \Drupal\views\Plugin\views\field\FieldHandlerBase. They must be
+ * annotated with \Drupal\views\Annotation\ViewsField annotation, and they
+ * must be in namespace directory Plugin\views\field.
+ *
+ * The following items can go into a hook_views_data() implementation in a
+ * field section to affect how the field handler will behave:
+ * - additional fields: An array of fields that should be added to the query.
+ *   The array is in the form of:
+ *   @code
+ *   array('identifier' => array('table' => tablename, 'field' => fieldname))
+ *   @endcode
+ *   As many fields as are necessary may be in this array.
+ * - click sortable: If TRUE (default), this field may be click sorted.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
  * Base field handler that has no options and renders an unformatted field.
- *
- * Definition terms:
- * - additional fields: An array of fields that should be added to the query
- *                      for some purpose. The array is in the form of:
- *                      array('identifier' => array('table' => tablename,
- *                      'field' => fieldname); as many fields as are necessary
- *                      may be in this array.
- * - click sortable: If TRUE, this field may be click sorted.
- *
- * @ingroup views_field_handlers
  */
 abstract class FieldPluginBase extends HandlerBase {
 

core/modules/views/src/Plugin/views/filter/FilterPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\filter\FilterPluginBase.
+ * Contains \Drupal\views\Plugin\views\filter\FilterPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\filter;
@@ -14,30 +14,33 @@ use Drupal\views\Plugin\views\display\DisplayPluginBase;
 use Drupal\views\ViewExecutable;
 
 /**
- * @defgroup views_filter_handlers Views filter handlers
+ * @defgroup views_filter_handlers Views filter handler plugins
  * @{
- * Handlers to tell Views how to filter queries.
+ * Plugins that handle views filtering.
  *
- * Definition items:
+ * Filter handler plugins extend
+ * \Drupal\views\Plugin\views\filter\FilterHandlerBase. They must be annotated
+ * with \Drupal\views\Annotation\ViewsFilter annotation, and they must be in
+ * namespace directory Plugin\views\filter.
+ *
+ * The following items can go into a hook_views_data() implementation in a
+ * filter section to affect how the filter handler will behave:
  * - allow empty: If true, the 'IS NULL' and 'IS NOT NULL' operators become
  *   available as standard operators.
  *
- * Object flags:
+ * You can refine the behavior of filters by setting the following Boolean
- *  You can set some specific behavior by setting up the following flags on
+ * member variables to TRUE in your plugin class:
- *  your custom class.
+ * - $alwaysMultiple: Disable the possibility of forcing a single value.
+ * - $no_operator: Disable the possibility of using operators.
+ * - $always_required: Disable the possibility of allowing an exposed input to
+ *   be optional.
  *
- * - alwaysMultiple:
+ * @ingroup views_plugins
- *    Disable the possibility to force a single value.
+ * @see plugin_api
- * - no_operator:
- *    Disable the possibility to use operators.
- * - always_required:
- *    Disable the possibility to allow a exposed input to be optional.
  */
 
 /**
- * Base class for filters.
+ * Base class for Views filters handler plugins.
- *
- * @ingroup views_filter_handlers
  */
 abstract class FilterPluginBase extends HandlerBase {
 

core/modules/views/src/Plugin/views/join/JoinPluginBase.php

@@ -10,15 +10,22 @@ namespace Drupal\views\Plugin\views\join;
 use Drupal\Core\Plugin\PluginBase;
 
 /**
- * @defgroup views_join_handlers Views join handlers
+ * @defgroup views_join_handlers Views join handler plugins
  * @{
- * Handlers to tell Views how to join tables together.
+ * Handler plugins for Views table joins.
  *
- * Here is an example how to join from table one to example two so it produces
+ * Handler plugins help build the view query object. Join handler plugins
- * the following sql:
+ * handle table joins.
+ *
+ * Views join handlers extend \Drupal\views\Plugin\views\join\JoinPluginBase.
+ * They must be annotated with \Drupal\views\Annotation\ViewsJoin annotation,
+ * and they must be in namespace directory Plugin\views\join.
+ *
+ * Here is an example of how to join from table one to table two so it produces
+ * the following SQL:
  * @code
  * INNER JOIN {two} ON one.field_a = two.field_b
- * @code.
+ * @endcode
  * The required php code for this kind of functionality is the following:
  * @code
  * $configuration = array(
@@ -29,9 +36,9 @@ use Drupal\Core\Plugin\PluginBase;
  *   'operator' => '='
  * );
  * $join = Views::pluginManager('join')->createInstance('standard', $configuration);
+ * @endcode
  *
- * To do complex joins:
+ * Here is an example of a more complex join:
- *
  * @code
  * class JoinComplex extends JoinPluginBase {
  *   public function buildJoin($select_query, $table, $view_query) {
@@ -41,6 +48,9 @@ use Drupal\Core\Plugin\PluginBase;
  *   }
  * }
  * @endcode
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/join/Standard.php

@@ -10,6 +10,8 @@ namespace Drupal\views\Plugin\views\join;
 /**
  * Default implementation of the join plugin.
  *
+ * @ingroup views_join_handlers
+ *
  * @ViewsJoin("standard")
  */
 class Standard extends JoinPluginBase {

core/modules/views/src/Plugin/views/join/Subquery.php

@@ -9,13 +9,17 @@ namespace Drupal\views\Plugin\views\join;
 
 /**
  * Join handler for relationships that join with a subquery as the left field.
- * E.g:
- *  LEFT JOIN node node_term_data ON ([YOUR SUBQUERY HERE]) = node_term_data.nid
  *
- * Join definition:
+ * For example:
- *   same as \Drupal\views\Plugin\views\join\JoinPluginBase, except:
+ * @code
- *   - left_query: The subquery to use in the left side of the join clause.
+ * LEFT JOIN node node_term_data ON ([YOUR SUBQUERY HERE]) = node_term_data.nid
+ * @endcode
  *
+ * Join definition: same as \Drupal\views\Plugin\views\join\JoinPluginBase,
+ * except:
+ * - left_query: The subquery to use in the left side of the join clause.
+ *
+ * @ingroup views_join_handlers
  * @ViewsJoin("subquery")
  */
 class Subquery extends JoinPluginBase {

core/modules/views/src/Plugin/views/pager/PagerPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\pager\PagerPluginBase.
+ * Contains \Drupal\views\Plugin\views\pager\PagerPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\pager;
@@ -13,43 +13,22 @@ use Drupal\views\ViewExecutable;
 /**
  * @defgroup views_pager_plugins Views pager plugins
  * @{
- * The base plugin to handler pagers of a view.
+ * Plugins to handle paging in views.
  *
- * The pager takes care about altering the query for its needs, altering some
+ * Pager plugins take care of everything regarding pagers, including figuring
- * global information of pagers and finally rendering itself.
+ * out the total number of items to render, setting up the query for paging,
+ * and setting up the pager.
+ *
+ * Pager plugins extend \Drupal\views\Plugin\views\pager\PagerPluginBase. They
+ * must be annotated with \Drupal\views\Plugin\Annotation\ViewsPager annotation,
+ * and they must be in namespace directory Plugin\views\pager.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
- * The base plugin to handle pager.
+ * Base class for views pager plugins.
- *
- * Pager plugins take care of everything regarding pagers, including getting
- * and setting the total number of items to render the pager and setting the
- * global pager arrays.
- *
- * To define a pager type, extend this base class. The ViewsPluginManager (used
- * to create views plugins objects) adds annotated discovery for pager plugins.
- * Your pager plugin must have an annotation that includes the plugin's metadata,
- * for example:
- * @code
- * @ Plugin(
- *   id = "demo_pager",
- *   title = @ Translation("Display a demonstration pager"),
- *   help = @ Translation("Demonstrate pagination of views items."),
- *   theme = "views_demo_pager"
- * )
- * @endcode
- * Remove spaces after @ in your actual plugin - these are put into this sample
- * code so that it is not recognized as annotation.
- *
- * The plugin annotation contains these components:
- * - id: The unique identifier of your pager plugin.
- * - title: The "full" title for your pager type; used in the views UI.
- * - short_title: (optional) The "short" title for your pager type;
- *   used in the views UI when specified.
- * - help: (optional) A short help string; this is displayed in the views UI.
- * - theme: The theme function used to render the pager's output.
- *
- * @see \Drupal\views\Plugin\ViewsPluginManager
  */
 abstract class PagerPluginBase extends PluginBase {
 

core/modules/views/src/Plugin/views/query/QueryPluginBase.php

@@ -13,7 +13,26 @@ use Drupal\views\ViewExecutable;
 use Drupal\views\Views;
 
 /**
- * @todo.
+ * @defgroup views_query_plugins Views query plugins
+ * @{
+ * Plugins for views queries.
+ *
+ * Query plugins generate and execute a built query object against a
+ * particular storage backend, converting the Views query object into an
+ * actual query. Although query plugins need not necessarily use SQL, most
+ * other handler plugins that affect the query (fields, filters, etc.)
+ * implicitly assume that the query is using SQL.
+ *
+ * Query plugins extend \Drupal\views\Plugin\views\query\QueryPluginBase.
+ * They must be annotated with \Drupal\views\Plugin\Annotation\ViewsQuery
+ * annotation, and they must be in namespace directory Plugin\views\query.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
+ */
+
+/**
+ * Base plugin class for Views queries.
  */
 abstract class QueryPluginBase extends PluginBase {
 
@@ -267,3 +286,7 @@ abstract class QueryPluginBase extends PluginBase {
   }
 
 }
+
+/**
+ * @}
+ */

core/modules/views/src/Plugin/views/query/Sql.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\query\Sql.
+ * Contains \Drupal\views\Plugin\views\query\Sql.
  */
 
 namespace Drupal\views\Plugin\views\query;
@@ -17,7 +17,9 @@ use Drupal\views\ViewExecutable;
 use Drupal\views\Views;
 
 /**
- * @todo.
+ * Views query plugin for an SQL query.
+ *
+ * @ingroup views_query_plugins
  *
  * @ViewsQuery(
  *   id = "views_query",

core/modules/views/src/Plugin/views/relationship/RelationshipPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\relationship\RelationshipPluginBase.
+ * Contains \Drupal\views\Plugin\views\relationship\RelationshipPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\relationship;
@@ -16,7 +16,15 @@ use Drupal\views\Views;
 /**
  * @defgroup views_relationship_handlers Views relationship handlers
  * @{
- * Handlers to tell Views how to create alternate relationships.
+ * Plugins for handling views relationships.
+ *
+ * Relationship handlers extend
+ * \Drupal\views\Plugin\views\relationship\RelationshipHandlerBase. They must
+ * be annotated with \Drupal\views\Annotation\ViewsRelationship annotation,
+ * and they must be in namespace directory Plugin\views\relationship.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**

core/modules/views/src/Plugin/views/row/RowPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\row\RowPluginBase.
+ * Contains \Drupal\views\Plugin\views\row\RowPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\row;
@@ -14,15 +14,31 @@ use Drupal\views\Views;
 /**
  * @defgroup views_row_plugins Views row plugins
  * @{
- * Row plugins control how Views outputs an individual record.
+ * Plugins that control how Views outputs an individual record.
  *
- * They are tightly coupled to style plugins, in that a style plugin is what
+ * Row plugins handle rendering each individual record from the view results.
- * calls the row plugin.
+ * For instance, a row plugin could render fields, render an entire entity
+ * in a particular view mode, or render the raw data from the results.
+ *
+ * Row plugins are used by some (but not all) style plugins. They are not
+ * activated unless the style plugin sets them up. See the
+ * @link views_style_plugins Views style plugins topic @endlink for
+ * more information.
+ *
+ * Row plugins extend \Drupal\views\Plugin\views\row\RowPluginBase. They must
+ * be annotated with \Drupal\views\Plugin\Annotation\ViewsRow annotation, and
+ * they must be in namespace directory Plugin\views\row.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
- * Default plugin to view a single row of a table. This is really just a wrapper around
+ * Base class for Views row plugins.
- * a theme function.
+ *
+ * This is really just a wrapper around a theme hook. It renders a row
+ * of the result table by putting it into a render array with the set theme
+ * hook.
  */
 abstract class RowPluginBase extends PluginBase {
 

core/modules/views/src/Plugin/views/sort/SortPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\sort\SortPluginBase.
+ * Contains \Drupal\views\Plugin\views\sort\SortPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\sort;
@@ -10,15 +10,20 @@ namespace Drupal\views\Plugin\views\sort;
 use Drupal\views\Plugin\views\HandlerBase;
 
 /**
- * @defgroup views_sort_handlers Views sort handlers
+ * @defgroup views_sort_handlers Views sort handler plugins
  * @{
- * Handlers to tell Views how to sort queries.
+ * Plugins that handle sorting for Views.
+ *
+ * Sort handlers extend \Drupal\views\Plugin\views\sort:SortHandlerBase. They
+ * must be annotated with \Drupal\views\Annotation\ViewsSort annotation, and
+ * they must be in plugin directory Plugin\views\sort.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
  * Base sort handler that has no options and performs a simple sort.
- *
- * @ingroup views_sort_handlers
  */
 abstract class SortPluginBase extends HandlerBase {
 

core/modules/views/src/Plugin/views/style/StylePluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\style\StylePluginBase.
+ * Contains \Drupal\views\Plugin\views\style\StylePluginBase.
  */
 
 namespace Drupal\views\Plugin\views\style;
@@ -15,17 +15,28 @@ use Drupal\views\ViewExecutable;
 /**
  * @defgroup views_style_plugins Views style plugins
  * @{
- * Style plugins control how a view is rendered. For example, they
+ * Plugins that control how the collection of results is rendered in a view.
- * can choose to display a collection of fields, node_view() output,
- * table output, or any kind of crazy output they want.
  *
- * Many style plugins can have an optional 'row' plugin, that displays
+ * Style plugins control a view is displayed. For the most part, they are
- * a single record. Not all style plugins can utilize this, so it is
+ * object wrappers around theme templates. Examples of styles include HTML
- * up to the plugin to set this up and call through to the row plugin.
+ * lists, tables, full or teaser content views, etc.
+ *
+ * Many (but not all) style plugins have an optional row plugin, which
+ * displays a single record. Not all style plugins use row plugins, so it is
+ * up to the style plugin to set this up and call the row plugin. See the
+ * @link views_row_plugins Views row plugins topic @endlink for more
+ * information.
+ *
+ * Style plugins extend \Drupal\views\Plugin\views\style\StylePluginBase. They
+ * must be annotated with \Drupal\views\Plugin\Annotation\ViewsStyle
+ * annotation, and they must be in namespace directory Plugin\views\style.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
  */
 
 /**
- * Base class to define a style plugin handler.
+ * Base class for views style plugins.
  */
 abstract class StylePluginBase extends PluginBase {
 

core/modules/views/src/Plugin/views/wizard/Standard.php

@@ -8,6 +8,10 @@
 namespace Drupal\views\Plugin\views\wizard;
 
 /**
+ * Standard Views wizard plugin.
+ *
+ * @ingroup views_wizard_plugins
+ *
  * @ViewsWizard(
  *   id = "standard",
  *   derivative = "Drupal\views\Plugin\Derivative\DefaultWizardDeriver",

core/modules/views/src/Plugin/views/wizard/WizardInterface.php

@@ -2,13 +2,15 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\wizard\WizardInterface.
+ * Contains \Drupal\views\Plugin\views\wizard\WizardInterface.
  */
 
 namespace Drupal\views\Plugin\views\wizard;
 
 /**
  * Defines a common interface for Views Wizard plugins.
+ *
+ * @ingroup views_wizard_plugins
  */
 interface WizardInterface {
 

core/modules/views/src/Plugin/views/wizard/WizardPluginBase.php

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\views\Plugin\views\wizard\WizardPluginBase.
+ * Contains \Drupal\views\Plugin\views\wizard\WizardPluginBase.
  */
 
 namespace Drupal\views\Plugin\views\wizard;
@@ -16,7 +16,21 @@ use Drupal\views\Plugin\views\PluginBase;
 use Drupal\views\Plugin\views\wizard\WizardInterface;
 
 /**
- * Provides the interface and base class for Views Wizard plugins.
+ * @defgroup views_wizard_plugins Views wizard plugins
+ * @{
+ * Plugins for Views wizards.
+ *
+ * Wizard handlers implement \Drupal\views\Plugin\views\wizard\WizardInterface,
+ * and usually extend \Drupal\views\Plugin\views\wizard\WizardPluginBase. They
+ * must be annotated with \Drupal\views\Annotation\ViewsWizard annotation,
+ * and they must be in namespace directory Plugin\views\wizard.
+ *
+ * @ingroup views_plugins
+ * @see plugin_api
+ */
+
+/**
+ * Base class for Views wizard plugins.
  *
  * This is a very generic Views Wizard class that can be constructed for any
  * base table.
@@ -1191,3 +1205,7 @@ abstract class WizardPluginBase extends PluginBase implements WizardInterface {
   }
 
 }
+
+/**
+ * @}
+ */

core/modules/views/src/ViewExecutable.php

@@ -16,13 +16,8 @@ use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 
 /**
- * @defgroup views_objects Objects that represent a View or part of a view
+ * Represents a view as a whole.
- * @{
+ *
- * These objects are the core of Views do the bulk of the direction and
- * storing of data. All database activity is in these objects.
- */
-
-/**
  * An object to contain all of the data to generate a view, plus the member
  * functions to build the view query, execute the query and render the output.
  */

core/modules/views/views.api.php

@@ -7,85 +7,45 @@
 
 use Drupal\Core\Language\LanguageInterface;
 
+/**
+ * @defgroup views_overview Views overview
+ * @{
+ * Overview of the Views module API
+ *
+ * The Views module is a generalized query and display engine, which can be used
+ * to make views (formatted lists, grids, feeds, and other output) of items
+ * (often entities, but can be other types of data). Developers can interact
+ * with Views in several ways:
+ * - Provide plugins: Views plugins govern nearly every aspect of views,
+ *   including querying (sorting, filtering, etc.) and display (at several
+ *   levels of granularity, ranging from the entire view to the details of a
+ *   field). See the @link views_plugins Views plugins topic @endlink for
+ *   more information.
+ * - Provide data: Data types can be provided to Views by implementing
+ *   hook_views_data(), and data types provided by other modules can be
+ *   altered by implementing hook_views_data_alter().
+ * - Implement hooks: A few operations in Views can be influenced by hooks.
+ *   See the @link Views hooks topic @endlink for a list.
+ * - Theming: See the @link views_templates Views templates topic @endlink
+ *   for more information.
+ *
+ * @see \Drupal\views\ViewExecutable
+ * @}
+ */
+
 /**
  * @defgroup views_plugins Views plugins
  *
  * Views plugins are objects that are used to build and render the view.
- * Plugins are registered by extending one of the Views base plugin classes
+ * See individual views plugin topics for more information about the
- * and defining settings in the plugin annotation. For more information about
+ * specifics of each plugin type, and the
- * plugins, see the @link plugin_api Plugin API topic. @endlink
+ * @link plugin_api Plugin API topic @endlink for more information about
+ * plugins in general.
  *
- * Views has the following types of plugins:
+ * Some Views plugins are known as handlers. Handler plugins help build the
- * - Access: Access plugins are responsible for controlling access to the
+ * view query object: filtering, contextual filtering, sorting, relationships,
- *   view. Views includes plugins for checking user roles and individual
+ * etc.
- *   permissions. Access plugins extend
- *   \Drupal\views\Plugin\views\access\AccessPluginBase.
- * - Argument default: Argument default plugins allow pluggable ways of
- *   providing default values for contextual filters. This is useful for
- *   blocks and other display types lacking a natural argument input.
- *   Examples are plugins to extract node and user IDs from the URL. Argument
- *   default plugins extend
- *   \Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase.
- * - Argument validator: Validator plugins can ensure arguments are valid,
- *   and even do transformations on the arguments. They can also provide
- *   replacement patterns for the view title. For example, the 'content'
- *   validator verifies verifies that the argument value corresponds to a
- *   node, loads that node and provides the node title as a replacement
- *   pattern. Argument validator plugins extend
- *   \Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase.
- * - Cache: Cache plugins control the storage and loading of caches.
- *   Currently they can do both result and render caching. It might also be
- *   possible to cache the generated query. Cache plugins extend
- *   \Drupal\views\Plugin\views\cache\CachePluginBase.
- * - Display: Display plugins are responsible for controlling where a View is
- *   rendered; that is, how it is exposed to other parts of Drupal. 'Page'
- *   and 'block' are the most commonly used display plugins. Each View also
- *   has a 'master' (or 'default') display that includes information shared
- *   between all its displays. (See
- *   \Drupal\views\Plugin\views\display\DefaultDisplay.) Display plugins extend
- *   \Drupal\views\Plugin\views\display\DisplayPluginBase.
- * - Display extender: Display extender plugins allow additional options or
- *   configurations to added to views across all display types. For example,
- *   if you wanted to allow site users to add certain metadata to the rendered
- *   output of every view display regardless of display type, you could provide
- *   this option as a display extender. Display extender plugins extend
- *   \Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase.
- * - Exposed form: Exposed form plugins are responsible for building,
- *   rendering, and controlling exposed forms. Exposed form plugins extend
- *   \Drupal\views\Plugin\views\display\DisplayPluginBase.
- * - Handlers: Handler plugins help build the view query object that the query
- *   plugin then executes to retrieve the data from the storage backend (see
- *   below). There are several types of handlers:
- *   - Area handlers: Extend \Drupal\views\Plugin\views\area\AreaHandlerBase
- *   - Argument handlers: Extend
- *     \Drupal\views\Plugin\views\argument\ArgumentHandlerBase
- *   - Field handlers: Extend \Drupal\views\Plugin\views\field\FieldHandlerBase
- *   - Filter handlers: Extend
- *     \Drupal\views\Plugin\views\filter\FilterHandlerBase
- *   - Relationship handlers:
- *     Extend \Drupal\views\Plugin\views\relationship\RelationshipHandlerBase
- *   - Sort handlers: Extend \Drupal\views\Plugin\views\sort:SortHandlerBase
- * - Pager: Pager plugins take care of everything regarding pagers, including
- *   getting setting the total number of items to render the pager and
- *   setting the global pager arrays. Pager plugins extend
- *   \Drupal\views\Plugin\views\pager\PagerPluginBase.
- * - Query: Query plugins generate and execute a built query object against a
- *   particular storage backend, converting the Views query object into an
- *   actual query. The only default implementation is SQL. (Note that most
- *   handler plugins currently rely on the SQL query plugin.) Query plugins
- *   extend \Drupal\views\Plugin\views\query\QueryPluginBase.
- * - Row style: Row styles handle rendering each individual record from the
- *   main view table. The two default implementations render the entire entity
- *   (nodes only), or selected fields. Row style plugins extend
- *   \Drupal\views\Plugin\views\row\RowPluginBase).
- * - Style: Style plugins control how a view is displayed. For the most part
- *   they are object wrappers around theme templates. Examples of styles
- *   include HTML lists, tables, etc. Style plugins extend
- *   \Drupal\views\Plugin\views\style\StylePluginBase.
  *
- * @todo Add an explanation for each type of handler.
- * @todo Add @ingroup to all the base plugins for this group.
- * @todo Add a separate @ingroup for all plugins?
  * @todo Document specific options on the appropriate plugin base classes.
  * @todo Add examples.
  *