// 
// Queue Class
//
// This is my Queue class. Its members are Proc objects.
class Queue {
    private int queueSize;
    private Proc theQueue[];
    private int nextFree;

    // Constructor for the Queue class.
    // Its MUST receive as argument the maximum queue size.
    Queue(int size) {
        queueSize = size;
        nextFree = 0;
        theQueue = new Proc[size];
    }

    // Returns TRUE if the queue is full.
    public boolean isFull() {
        return (queueSize == nextFree);
    }

    // returns TRUE if the queue is empty.
    public boolean isEmpty() {
        return (nextFree == 0); 
    }

    // Returns the number of processes currently in the queue.
    public int length() {
        return nextFree;
    }

    // Reads the time left in the i-th process in the queue 
    public int getTime(int i) {
        return theQueue[i].getTime();
    }

    // Reads the process name of the i-th process in the queue
    public String getName(int i) {
        return theQueue[i].getName();
    }

    // Reads the creationTime of the first process in the queue
    public float getCreation() {
        return theQueue[0].getCreation();
    }

    // Changes the time left for the process being served by the CPU
    // which is always process 0.
    public void setTime(int i, int time) {
        theQueue[i].setTime(time);
    }

    // This method adds a new process to the queue. It receives as
    // arguments the desired process execution time.
    // Processes are always added to the end of the queue.
    //
    public synchronized void enqueue(Proc newProcess) {
        if (isFull()) {
//          System.out.println("Cannot add process. Queue is full");
        }
        else {
            theQueue[nextFree] = newProcess;
            nextFree++;
        }
    }

    // This method removes the process at the beginning of the queue.
    // All other processes are rotated towards the beginning of the queue.
    public synchronized void dequeue() {
        if (isEmpty()) {
//            System.out.println("Cannot delete process. Queue is empty");
        }
        else {
            for (int i = 1; i < nextFree; i++) {
                theQueue[i - 1] = theQueue[i];
            }
            nextFree--;
        }
    }

    // This method rotates the queue, so that Queue[0] is always the
    // element being serviced by the CPU.
    public void rotate() {
        /* rotating an empty queue is harmless. (I think!)  */
        if (!isEmpty()) {
            Proc temp = theQueue[0];
            
            for (int i = 1; i < nextFree; i++) {
                theQueue[i-1] = theQueue[i];
            }
            theQueue[nextFree - 1] = temp;
        }
    }

//    For debugging purposes:    
//    public void printQueue() {
//        for (int i = 0; i < nextFree; i++) {
//            System.out.print("Queue[" + i + "] ");
//            System.out.println(theQueue[i].getTime());
//        }
//    }
}