I need help with defining my Comparator cmp to use in other methods in class heap. the comparator uses the ArrayList tree

/**

* A complete tree stored in an array list representing this

* binary heap

*/

public ArrayList tree;

/**

* A comparator lambda function that compares two elements of this

* heap when rebuilding it; cmp.compare(x,y) gives 1. negative when x less than y

* 2. positive when x greater than y 3. 0 when x equal y

*/

private Comparatorsuper E> cmp;

cmp =fn

/**

* Constructs an empty heap using the compareTo method of its data type as the

* comparator

*/

public Heap() {

tree = new ArrayList();

}

/**

* A parameterized constructor that uses an externally defined comparator

* @param fn - a trichotomous integer value comparator function

*/

public Heap(Comparatorsuper E> fn) {

}