2 Extend the PriorityQueue class: 2.1 Write code for the method void clear() which empties the heap and resets the size to 0. 2.2 Write code for the method Boolean isEmpty () that checks whether the heap contains any elements or not. 2.3 Write code for the method Boolean add (Node x) which adds a new node to the heap 2.4 Write code for the method Node remove ( ) which deletes the root, decreases the heap size and reorders the remaining heap. It should involve a call to a method percolate Down (int hole). 3 2.1 Create a file Main.java in which to write your code for this question. 2.2 Write code for a main method to build a Min Heap from the data in flights.txt You will need to write code that performs String pre-processing. This means transform the raw data into the appropriate Node attributes and calculate the arrival time, before creating a Node and adding it to the Heap. The heap should be ordered by arrival time. 2.3 In the main method, print out the order in which incoming flights should land. Sample data: flights.txt registration_no, departure_timestamp, flight duration (hh:mm:ss) ZA7117,14:01:36,3:33:22 ZA3642,18:06:20,5:33:59 ZA5453,23:43:56,4:21:13 ZA0559,16:09:05,8:58:24 ZA6903,13:54:48, 11:59:58 ZA9604,12:29:53,9:09:07 ZA5348,2:59:13, 6:23:48 ZA3835,8:42:41,14:55:44 ZA4949, 12:42:13,3:05:13 ZA2951,23:40:10,8:05:41 ZA4940, 9:11:30, 12:25:47 ZA3121,4:42:50, 7:53:03 ZA6470,22:59:30, 10:03:19 ZA4981, 19:37:53,12:58:38 ZA0647,9:19:03,14:50:22 ZA5632,12:23:53,1:46:22 ZA2321,20:46:09,5:07:25 ZA3408,22:48:49,1:17:55 ZA2851,4:28:12,13:45:53 ZA7759,18:35:41,4:25:57 setting up Study the class definitions below: class Node // attributes String flight_no; // flight number Date arrival time; // time at which flight lands class PriorityQueue // attributes int currentSize; Node root; FlightNode[] array new Node [25]; // methods void clear(); Boolean isEmpty(); Boolean add (Node x); Node remove(); void percolate Down (int hole); .1 Create two files Node.java and PriorityQueue.java .2 Copy the above definitions into the corresponding files .3 Write code for a default and a loaded constructor for Node .4 Write code for a default and a loaded constructor for PriorityQueue .5 Write accessor and mutator methods for the attributes of Node .6 Write accessor and mutator methods for the attributes of PriorityQueue