/* -------------------------------------------------------- *
 * Aaron Morris                                             *
 * CS522                                                    *
 * Object-Oriented Event-Driven Simulation                  *
 *                                                          *
 * Class representing Request List.  Queue of requests.       *
 * Events are added in sorted order                         *
 * -------------------------------------------------------- */
//package datasend;
import java.awt.*;

public class MessageQueue {

        protected Message messageList;     // Start of Event List
        protected Message tail;           // End of list
        protected int numQueued;          // Number of Items in List


	/* Basic Object Constructor, creating Queue to store requests */
 	public MessageQueue()
    	{
                this.messageList = null;
                this.tail = null;
                this.numQueued = 0;
    	}

        // Method to return number of Queued objects
	public int getNumQueued() { return this.numQueued; }

        // Method to remove and return first request in Queue
	public Message deQueue()
	{
            Message temp;
            temp = messageList;

            // If there are queued members
            if (numQueued > 0)
            {
              messageList = messageList.getNext();
              if (messageList == null) tail = null;
              temp.setNext(null);
              numQueued--;
            }
            else { System.out.println("Tried to DeQueue when Q Empty"); }
            return temp;
	}


        // Method to add a Message to the list
	public void enQueue(Message ev)
	{
            Message temp,temp2;

            // If will be first request in list
            if (numQueued == 0)
            {
                messageList = ev;
                tail = ev;
            }

            // If adding at end
            else
            {
                tail.setNext(ev);
                tail = ev;
            }

         numQueued++;
        }

        // For Testing purposes, print out current requestList
        public void PrintQueue()
        {
            Message temp = messageList;
            System.out.print("messageList[" + numQueued + "]: ");
            while (temp != null)
            {
                System.out.print(" ");
                System.out.print(temp.getStringRep());
                temp = temp.getNext();
            }
            System.out.println ("   END OF LIST");
        }
}