public function register_routes() {
		register_rest_route(
			$this->namespace,
			'/' . $this->rest_base,
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_items' ),
					'permission_callback' => array( $this, 'get_items_permissions_check' ),
					'args'                => $this->get_collection_params(),
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'create_item' ),
					'permission_callback' => array( $this, 'create_item_permissions_check' ),
					'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::CREATABLE ),
				),
				'schema' => array( $this, 'get_item_schema' ),
			)
		);

		// Attention: (?P<id>[\d]+) is the placeholder for **Thread** ID, not the Message ID one.
		$thread_endpoint = '/' . $this->rest_base . '/(?P<id>[\d]+)';

		register_rest_route(
			$this->namespace,
			$thread_endpoint,
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_item' ),
					'permission_callback' => array( $this, 'get_item_permissions_check' ),
					'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::READABLE ),
				),
				array(
					'methods'             => WP_REST_Server::EDITABLE,
					'callback'            => array( $this, 'update_item' ),
					'permission_callback' => array( $this, 'update_item_permissions_check' ),
					'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::EDITABLE ),
				),
				array(
					'methods'             => WP_REST_Server::DELETABLE,
					'callback'            => array( $this, 'delete_item' ),
					'permission_callback' => array( $this, 'delete_item_permissions_check' ),
					'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::DELETABLE ),
				),
				'schema' => array( $this, 'get_item_schema' ),
			)
		);

		// Register the starred route.
		if ( bp_is_active( 'messages', 'star' ) ) {
			// Attention: (?P<id>[\d]+) is the placeholder for **Message** ID, not the Thread ID one.
			$starred_endpoint = '/' . $this->rest_base . '/' . bp_get_messages_starred_slug() . '/(?P<id>[\d]+)';

			register_rest_route(
				$this->namespace,
				$starred_endpoint,
				array(
					'args'   => array(
						'id' => array(
							'description' => __( 'ID of one of the message of the Thread.', 'buddypress' ),
							'type'        => 'integer',
						),
					),
					array(
						'methods'             => WP_REST_Server::EDITABLE,
						'callback'            => array( $this, 'update_starred' ),
						'permission_callback' => array( $this, 'update_starred_permissions_check' ),
					),
					'schema' => array( $this, 'get_item_schema' ),
				)
			);
		}
	}