interface FieldableEntityInterface

interface FieldableEntityInterface extends EntityInterface {
    
    /**
     * Provides base field definitions for an entity type.
     *
     * Implementations typically use the class
     * \Drupal\Core\Field\BaseFieldDefinition for creating the field definitions;
     * for example a 'name' field could be defined as the following:
     * @code
     * $fields['name'] = BaseFieldDefinition::create('string')
     *   ->setLabel(t('Name'));
     * @endcode
     *
     * By definition, base fields are fields that exist for every bundle. To
     * provide definitions for fields that should only exist on some bundles, use
     * \Drupal\Core\Entity\FieldableEntityInterface::bundleFieldDefinitions().
     *
     * The definitions returned by this function can be overridden for all
     * bundles by hook_entity_base_field_info_alter() or overridden on a
     * per-bundle basis via 'base_field_override' configuration entities.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition. Useful when a single class is used for multiple,
     *   possibly dynamic entity types.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of base field definitions for the entity type, keyed by field
     *   name.
     *
     * @see \Drupal\Core\Entity\EntityFieldManagerInterface::getFieldDefinitions()
     * @see \Drupal\Core\Entity\FieldableEntityInterface::bundleFieldDefinitions()
     */
    public static function baseFieldDefinitions(EntityTypeInterface $entity_type);
    
    /**
     * Provides field definitions for a specific bundle.
     *
     * This function can return definitions both for bundle fields (fields that
     * are not defined in $base_field_definitions, and therefore might not exist
     * on some bundles) as well as bundle-specific overrides of base fields
     * (fields that are defined in $base_field_definitions, and therefore exist
     * for all bundles). However, bundle-specific base field overrides can also
     * be provided by 'base_field_override' configuration entities, and that is
     * the recommended approach except in cases where an entity type needs to
     * provide a bundle-specific base field override that is decoupled from
     * configuration. Note that for most entity types, the bundles themselves are
     * derived from configuration (e.g., 'node' bundles are managed via
     * 'node_type' configuration entities), so decoupling bundle-specific base
     * field overrides from configuration only makes sense for entity types that
     * also decouple their bundles from configuration. In cases where both this
     * function returns a bundle-specific override of a base field and a
     * 'base_field_override' configuration entity exists, the latter takes
     * precedence.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition. Useful when a single class is used for multiple,
     *   possibly dynamic entity types.
     * @param string $bundle
     *   The bundle.
     * @param \Drupal\Core\Field\FieldDefinitionInterface[] $base_field_definitions
     *   The list of base field definitions.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of bundle field definitions, keyed by field name.
     *
     * @see \Drupal\Core\Entity\EntityFieldManagerInterface::getFieldDefinitions()
     * @see \Drupal\Core\Entity\FieldableEntityInterface::baseFieldDefinitions()
     *
     * @todo WARNING: This method will be changed in
     *   https://www.drupal.org/node/2346347.
     */
    public static function bundleFieldDefinitions(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions);
    
    /**
     * Determines whether the entity has a field with the given name.
     *
     * @param string $field_name
     *   The field name.
     *
     * @return bool
     *   TRUE if the entity has a field with the given name. FALSE otherwise.
     */
    public function hasField($field_name);
    
    /**
     * Gets the definition of a contained field.
     *
     * @param string $name
     *   The name of the field.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface|null
     *   The definition of the field or null if the field does not exist.
     */
    public function getFieldDefinition($name);
    
    /**
     * Gets an array of field definitions of all contained fields.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of field definitions, keyed by field name.
     *
     * @see \Drupal\Core\Entity\EntityFieldManagerInterface::getFieldDefinitions()
     */
    public function getFieldDefinitions();
    
    /**
     * Gets an array of all field values.
     *
     * Gets an array of plain field values, including only non-computed values.
     * Note that the structure varies by entity type and bundle.
     *
     * @return array
     *   An array of field values, keyed by field name.
     */
    public function toArray();
    
    /**
     * Gets a field item list.
     *
     * @param string $field_name
     *   The name of the field to get; e.g., 'title' or 'name'.
     *
     * @return \Drupal\Core\Field\FieldItemListInterface
     *   The field item list, containing the field items.
     *
     * @throws \InvalidArgumentException
     *   If an invalid field name is given.
     */
    public function get($field_name);
    
    /**
     * Sets a field value.
     *
     * @param string $field_name
     *   The name of the field to set; e.g., 'title' or 'name'.
     * @param mixed $value
     *   The value to set, or NULL to unset the field.
     * @param bool $notify
     *   (optional) Whether to notify the entity of the change. Defaults to
     *   TRUE. If the update stems from the entity, set it to FALSE to avoid
     *   being notified again.
     *
     * @return $this
     *
     * @throws \InvalidArgumentException
     *   If the specified field does not exist.
     */
    public function set($field_name, $value, $notify = TRUE);
    
    /**
     * Gets an array of all field item lists.
     *
     * @param bool $include_computed
     *   If set to TRUE, computed fields are included. Defaults to TRUE.
     *
     * @return \Drupal\Core\Field\FieldItemListInterface[]
     *   An array of field item lists implementing, keyed by field name.
     */
    public function getFields($include_computed = TRUE);
    
    /**
     * Gets an array of field item lists for translatable fields.
     *
     * @param bool $include_computed
     *   If set to TRUE, computed fields are included. Defaults to TRUE.
     *
     * @return \Drupal\Core\Field\FieldItemListInterface[]
     *   An array of field item lists implementing, keyed by field name.
     */
    public function getTranslatableFields($include_computed = TRUE);
    
    /**
     * Reacts to changes to a field.
     *
     * Note that this is invoked after any changes have been applied.
     *
     * @param string $field_name
     *   The name of the field which is changed.
     *
     * @throws \InvalidArgumentException
     *   When trying to assign a value to the language field that matches an
     *   existing translation.
     * @throws \LogicException
     *   When trying to change:
     *   - The language of a translation.
     *   - The value of the flag identifying the default translation object.
     */
    public function onChange($field_name);
    
    /**
     * Validates the currently set values.
     *
     * @return \Drupal\Core\Entity\EntityConstraintViolationListInterface
     *   A list of constraint violations. If the list is empty, validation
     *   succeeded.
     */
    public function validate();
    
    /**
     * Checks whether entity validation is required before saving the entity.
     *
     * @return bool
     *   TRUE if validation is required, FALSE if not.
     */
    public function isValidationRequired();
    
    /**
     * Sets whether entity validation is required before saving the entity.
     *
     * @param bool $required
     *   TRUE if validation is required, FALSE otherwise.
     *
     * @return $this
     */
    public function setValidationRequired($required);

}