# Directory

The Directory is backed by four `GET` endpoints in `DirectoryController.java`. Every level on the UI maps to one call; the display names and entity counts surfaced at level 1 are derived at request time by parsing the [ODDRN](/introduction/main-concepts.md#oddrn) of every registered data source through `oddrn-generator`'s `Generator.parse(...)`. For the level-by-level walkthrough and the relationship to the Catalog Overview surface, see the [Directory](/features/data-discovery/directory.md) page.

| Method | Path                                                                              | Operation ID                 | Purpose                                                                                                                                             |
| ------ | --------------------------------------------------------------------------------- | ---------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| `GET`  | `/api/directory`                                                                  | `getDataSourceTypes`         | Level 1 — list every ODDRN-prefix that has at least one registered data source, with display name and entity count.                                 |
| `GET`  | `/api/directory/datasources?prefix={type-prefix}`                                 | `getDirectoryDatasourceList` | Level 2 — list registered data sources for the given prefix; each result carries the source's ODDRN-derived properties and per-source entity count. |
| `GET`  | `/api/directory/datasources/{data_source_id}/types`                               | `getDatasourceEntityTypes`   | Level 3 — list `DataEntityType` values present in the given data source.                                                                            |
| `GET`  | `/api/directory/datasources/{data_source_id}?type_id={type-id}&page={n}&size={m}` | `getDatasourceEntities`      | Level 4 — paged list of entities of the chosen type within the chosen data source. Delegates to `DataEntityService`.                                |

## See also

* [API Reference hub](/developer-guides/api-reference.md) — the full per-feature index.
* [Directory](/features/data-discovery/directory.md) — feature description, four-level walkthrough, UI entry points.


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