自定義隊列ArrayQueue

Queue 先進先出（FIFO）first in firtst out 的數據結構。

void enqueue(e) 入隊
dequeue() 出隊
getFront() 隊首
getSize() 大小
isEmpty(); 是否空

/**
 * 先進先出
 *
 * @param <E>
 */
public class ArrayQueue<E> implements Queue<E> {

    private final Array<E> eArray;

    public ArrayQueue() {
        this.eArray = new Array<>(10);

    }

    public ArrayQueue(int capacity) {
        eArray = new Array<>(capacity);

    }

    @Override
    public int getSize() {
        return eArray.size();
    }

    @Override
    public boolean isEmpty() {
        return eArray.size() == 0;
    }

    //出隊，刪除最後一個
    @Override
    public E dequeue() {
        return eArray.removeLast();
    }

    //    入隊
    @Override
    public void enqueue(E e) {
        eArray.addLast(e);
    }

    //獲取隊首
    @Override
    public E getFront() {
        return eArray.get(0);
    }

    @Override
    public String toString() {
        StringBuilder stringBuilder = new StringBuilder();

        stringBuilder.append("ArrayQueue");
        stringBuilder.append("   front:[");
        for (int i = 0; i < eArray.size(); i++) {
            stringBuilder.append(eArray.get(i));
            if (i != eArray.size() - 1) {
                stringBuilder.append(", ");
            }
        }
        stringBuilder.append("] tail");
        return stringBuilder.toString();


    }

    public static void main(String[] args) {
        final ArrayQueue<Integer> integerArrayQueue = new ArrayQueue<>();

        for (int i = 0; i < 10; i++) {
            integerArrayQueue.enqueue(i);
            System.out.println(integerArrayQueue);
            if (i%3==2){
                integerArrayQueue.dequeue();
                System.out.println(integerArrayQueue);

            }
        }
    }
}