Generics and ArrayList to implement a priority queue

Question

I am stuck on an assignment which includes generics and ArrayList . The assignment is to implement a priority queue capable of holding objects of an arbitrary type T by defining a priority queue class that implements the queue with an ArrayList .

The method to be supported is Add(item, priority)

And depending on the priority remove() removes the highest item in the priority list.

I created the Generic Class with the type being T , declared private T data . Used multiple constructors to set data. Now I am stuck on how to use this class and Use ArrayList , as I am not sure you can add(string, integer) in an ArrayList let alone iterate through it.

Any tips and ideas on how to approach this homework will be greatly appreciated.

Answer 1

You simply need to wrap the data and its priority inside another object, only used internally by your PriorityQueue (just like a LinkedList uses nodes that wrap the data and a pointer to the next node).

So priorityQueue(T data, int priority) would end up being implemented as

Node node = new Node(data, priority);
// find the position where the node must be inserted
arrayList.add(position, node);