Defines an interface for entity field definitions.
An entity field is a data object that holds the values of a particular field for a particular entity (see \Drupal\Core\Field\FieldItemListInterface). For example, $node_1->body and $node_2->body contain different data and therefore are different field objects.
In contrast, an entity field *definition* is an object that returns information *about* a field (e.g., its type and settings) rather than its values. As such, if all the information about $node_1->body and $node_2->body is the same, then the same field definition object can be used to describe both.
It is up to the class implementing this interface to manage where the information comes from. For example, field.module provides an implementation based on two levels of configuration. It allows the site administrator to add custom fields to any entity type and bundle via the "field_storage_config" and "field_config" configuration entities. The former for storing configuration that is independent of which entity type and bundle the field is added to, and the latter for storing configuration that is specific to the entity type and bundle. The class that implements "field_config" configuration entities also implements this interface, returning information from either itself, or from the corresponding "field_storage_config" configuration, as appropriate.
However, entity base fields, such as $node->title, are not managed by field.module and its "field_storage_config"/"field_config" configuration entities. Therefore, their definitions are provided by different objects based on the class \Drupal\Core\Field\BaseFieldDefinition, which implements this interface as well.
Field definitions may fully define a concrete data object (e.g., $node_1->body), or may provide a best-guess definition for a data object that might come into existence later. For example, $node_1->body and $node_2->body may have different definitions (e.g., if the node types are different). When adding the "body" field to a View that can return nodes of different types, the View can get a field definition that represents the "body" field abstractly, and present Views configuration options to the administrator based on that abstract definition, even though that abstract definition can differ from the concrete definition of any particular node's body field.
Hierarchy
- interface \Drupal\Core\TypedData\ListDataDefinitionInterface; interface \Drupal\Core\Cache\CacheableDependencyInterface
- interface \Drupal\Core\Field\FieldDefinitionInterface
File
- core/lib/Drupal/Core/Field/FieldDefinitionInterface.php, line 51
Namespace
Drupal\Core\Field
Members
| Name | Modifiers | Type | Description |
|---|---|---|---|
| CacheableDependencyInterface::getCacheContexts | public | function | The cache contexts associated with this object. |
| CacheableDependencyInterface::getCacheMaxAge | public | function | The maximum age for which this object may be cached. |
| CacheableDependencyInterface::getCacheTags | public | function | The cache tags associated with this object. |
| DataDefinitionInterface::addConstraint | public | function | Adds a validation constraint. |
| DataDefinitionInterface::createFromDataType | public static | function | Creates a new data definition object. |
| DataDefinitionInterface::getClass | public | function | Returns the class used for creating the typed data object. |
| DataDefinitionInterface::getConstraint | public | function | Returns a validation constraint. |
| DataDefinitionInterface::getConstraints | public | function | Returns an array of validation constraints. |
| DataDefinitionInterface::getDataType | public | function | Returns the data type of the data. |
| DataDefinitionInterface::getDescription | public | function | Returns a human readable description. |
| DataDefinitionInterface::getLabel | public | function | Returns a human readable label. |
| DataDefinitionInterface::getSetting | public | function | Returns the value of a given setting. |
| DataDefinitionInterface::getSettings | public | function | Returns the array of settings, as required by the used class. |
| DataDefinitionInterface::isComputed | public | function | Determines whether the data value is computed. |
| DataDefinitionInterface::isList | public | function | Returns whether the data is multi-valued, i.e. a list of data items. |
| DataDefinitionInterface::isReadOnly | public | function | Determines whether the data is read-only. |
| FieldDefinitionInterface::getConfig | public | function | Gets an object that can be saved in configuration. |
| FieldDefinitionInterface::getDefaultValue | public | function | Returns the default value for the field in a newly created entity. |
| FieldDefinitionInterface::getDefaultValueCallback | public | function | Returns the default value callback for the field. |
| FieldDefinitionInterface::getDefaultValueLiteral | public | function | Returns the default value literal for the field. |
| FieldDefinitionInterface::getDisplayOptions | public | function | Returns the default display options for the field. |
| FieldDefinitionInterface::getFieldStorageDefinition | public | function | Returns the field storage definition. |
| FieldDefinitionInterface::getName | public | function | Returns the machine name of the field. |
| FieldDefinitionInterface::getTargetBundle | public | function | Gets the bundle the field is attached to. |
| FieldDefinitionInterface::getTargetEntityTypeId | public | function | Returns the ID of the entity type the field is attached to. |
| FieldDefinitionInterface::getType | public | function | Returns the field type. |
| FieldDefinitionInterface::isDisplayConfigurable | public | function | Returns whether the display for the field can be configured. |
| FieldDefinitionInterface::isRequired | public | function | Returns whether the field can be empty. Overrides DataDefinitionInterface::isRequired |
| FieldDefinitionInterface::isTranslatable | public | function | Returns whether the field is translatable. |
| ListDataDefinitionInterface::createFromItemType | public static | function | Creates a new list data definition for items of the given data type. |
| ListDataDefinitionInterface::getItemDefinition | public | function | Gets the data definition of an item of the list. |
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