구현 // 자료구조 // 큐(Queue) // RingBuffer // toJava

package question.stackqueue;

public class MyQueue {

    /* Main */
    public static void main(String[] args) {
        Queue<Integer> queue = new Queue(16);
        queue.add(1);
        queue.add(2);
        queue.add(3);
        System.out.println(queue.remove());
        System.out.println(queue.remove());
        System.out.println(queue.remove());
        System.out.println(queue.remove());
    }

    /* Queue - RingBuffer구현 */
    public static class Queue<T> {

        // == Field ==
        public int capacity;
        public int pointerFront;
        public int pointerBack;
        public int size;
        public T[] bucket;

        // == Constructor ==
        public Queue(int capacity) {
            this.capacity = capacity;
            this.pointerBack = 0;
            this.pointerFront = 0;
            this.size = 0;
            this.bucket = (T[]) new Object[capacity]; // * 제네릭객체 생성방법
        }

        // == add ==
        public void add(T t) {
            if(size < capacity) {
                this.bucket[pointerFront++] = t;
                size++;
                if(pointerFront >= capacity) pointerFront = 0;
            }
        }

        // == remove ==
        public T remove() {
            if(size > 0) {
                size--;
                T rtn = this.bucket[pointerBack++];
                if(pointerBack >= capacity) pointerBack = 0;
                return rtn;
            }
            return null;
        }

        // == peek ==
        public T peek() {
            if(size > 0) {
                return this.bucket[pointerBack];
            }
            return null;
        }

        // == isEmpty ==
        public boolean isEmpty() {
            return size == 0 ? true : false;
        }
    }
}