import java.util.Arrays;
import queue.QueueInterface;

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/**
 *
 * @author Student
 * @param <T>
 */
public class Queue <T> implements QueueInterface <T> {

    int head;
    int tail;
    int size;
    T[] queue;
    int capacity;
    boolean full;
    //int last;

    public Queue(int capacity){
       queue = (T[]) new Object[capacity];
       this.size = 0;
       this.head = 0;
       this.tail = -1;
       this.capacity = capacity;
    }
    @Override
    public void enqueue(T t) {

        this.tail++;

      if (tail == capacity && head!=0){
            this.tail = (tail)%capacity;
        }

      if(!isFull()){
          queue[tail] = t;
      }
      else{
         expand();
         enqueue(t);
        }
        this.size++;
    }

    @Override
    public T dequeue() {
        if(head!=capacity-1){
        this.head = head++;
        this.size = size--;
        }
        else{
           this.head = 0;
        }
        return queue[head];
    }

    @Override
    public T getFront() {
        return this.queue[head];
    }

    public boolean isFull(){
        if(capacity == size){
            full = true;
        }
        return full;
    }

    public void expand(){
    this.capacity = capacity*2;
    this.queue = Arrays.copyOf(queue, capacity);
    }
    /**
     *
     * @return
     */
    @Override
    public int getLength(){
        return this.size;
    }

}