UISearchDisplayController is part of Apple's UIKit framework. It greatly simplifies adding UISearchBars to UITableViews.
A UISearchDisplayController
manages the display of a search bar, along with a table view that displays search results.
You initialize a search display controller with a search bar and a view controller responsible for managing the data to be searched. When the user starts a search, the search display controller superimposes the search interface over the original view controller’s view and shows the search results in its table view. The searchDisplayController was deprecated in iOS version 8.0