ConfigEntityTypeInterface.php

<?php

namespace Drupal\Core\Config\Entity;

use Drupal\Core\Entity\EntityTypeInterface;

/**
 * Provides an interface for a configuration entity type and its metadata.
 */
interface ConfigEntityTypeInterface extends EntityTypeInterface {
    
    /**
     * Length limit of the configuration entity prefix.
     *
     * Configuration entity names are composed of two parts:
     * - The config prefix, which is returned by getConfigPrefix() and is
     *   composed of:
     *   - The provider module name (limited to 50 characters by
     *     DRUPAL_EXTENSION_NAME_MAX_LENGTH).
     *   - The module-specific namespace identifier, which defaults to the
     *     configuration entity type ID. Entity type IDs are limited to 32
     *     characters by EntityTypeInterface::ID_MAX_LENGTH.
     * - The configuration entity ID.
     * So, a typical configuration entity filename will look something like:
     * provider_module_name.namespace_identifier.config_entity_id.yml
     *
     * Most file systems limit a file name's length to 255 characters, so
     * ConfigBase::MAX_NAME_LENGTH restricts the full configuration object name
     * to 250 characters (leaving 5 for the file extension). Therefore, in
     * order to leave sufficient characters to construct a configuration ID,
     * the configuration entity prefix is limited to 83 characters: up to 50
     * characters for the module name, 1 for the dot, and 32 for the namespace
     * identifier. This also allows modules with shorter names to define longer
     * namespace identifiers if desired.
     *
     * @see \Drupal\Core\Config\ConfigBase::MAX_NAME_LENGTH
     * @see \Drupal\Core\Config\Entity\ConfigEntityTypeInterface::getConfigPrefix()
     * @see DRUPAL_EXTENSION_NAME_MAX_LENGTH
     * @see \Drupal\Core\Config\Entity\ConfigEntityStorage::MAX_ID_LENGTH
     * @see \Drupal\Core\Entity\EntityTypeInterface::ID_MAX_LENGTH
     */
    const PREFIX_LENGTH = 83;
    
    /**
     * Gets the config prefix used by the configuration entity type.
     *
     * The config prefix is used to prefix configuration entity IDs when they are
     * stored in the configuration system. The default config prefix is
     * constructed from the name of the module that provides the entity type and
     * the ID of the entity type. If a config_prefix annotation is present it will
     * be used in place of the entity type ID.
     *
     * Prefixing with the module that provides the configuration entity type
     * ensures that configuration entities depend on the module that provides the
     * configuration entity type.
     *
     * @return string
     *   The config prefix.
     *
     * @throws \Drupal\Core\Config\ConfigPrefixLengthException
     *   Exception thrown when the length of the prefix exceeds PREFIX_LENGTH.
     */
    public function getConfigPrefix();
    
    /**
     * Gets the config entity properties to export if declared on the annotation.
     *
     * @param string $id
     *   The ID of the configuration entity.
     *
     * @return array|null
     *   The properties to export or NULL if they can not be determine from the
     *   config entity type annotation.
     */
    public function getPropertiesToExport($id = NULL);
    
    /**
     * Gets the keys that are available for fast lookup.
     *
     * @return string[]
     *   The list of lookup keys.
     */
    public function getLookupKeys();

}