package queue;import array.Array;/** * @Title: ArrayQueue * @ProjectName Demo03 * @date 2018/9/1214:09 */public class ArrayQueue
     
       implements Queue
      
        {    private Array
       
         array;    public ArrayQueue() {        array = new Array<>();    }    public ArrayQueue(int capacity) {        array = new Array<>(capacity);    }    @Override    public int getSize() {        return array.getSize();    }    @Override    public boolean isEmpty() {        return array.isEmpty();    }    @Override    public void enqueue(E e) {        array.addLast(e);    }    @Override    public E dequeue() {        return array.removeFirst();    }    @Override    public E getFront() {        return array.getFirst();    }    @Override    public String toString() {        StringBuilder res = new StringBuilder();        res.append("Queue:");        res.append("Front [");        for (int i = 0; i < array.getSize(); i++) {            res.append(array.get(i));            if (i != array.getSize() - 1) {                res.append(",");            }        }        res.append("] tail");        return res.toString();    }    public static void main(String[] args) {        ArrayQueue
        
          arrayQueue = new ArrayQueue<>();        arrayQueue.enqueue("1");        arrayQueue.enqueue("2");        System.out.println(arrayQueue);        System.out.println(arrayQueue.getFront());        arrayQueue.dequeue();        System.out.println(arrayQueue);    }}
        
       
      
     

　

package queue;/** * @Title: LoopQueue * @ProjectName Demo03 * @date 2018/9/1214:17 */public class LoopQueue
     
       implements Queue
      
        {    private E[] data;    // 元素所在位置,元素入队下一个位置    private int front, tail;    private int size;    public LoopQueue(int capacity) {        data = (E[]) new Object[capacity + 1];        front = 0;        tail = 0;        size = 0;    }    public LoopQueue() {        this(10);    }    @Override    public int getSize() {        return size;    }    @Override    public boolean isEmpty() {        return front == tail;    }    public int getCapacity() {        return data.length - 1;    }    @Override    public void enqueue(E e) {        if ((tail + 1) % data.length == front) {            // 队列已满            resize(getCapacity() * 2);        }        data[tail] = e;        tail = (tail + 1) % data.length;        size++;    }    @Override    public E dequeue() {        if (isEmpty()) {            throw new IllegalArgumentException("队列为空");        }        E e = data[front];        front = (front + 1) % data.length;        size--;        if (size == getCapacity() / 4 && getCapacity() / 2 != 0) {            resize(getCapacity() / 2);        }        return e;    }    @Override    public E getFront() {        if (isEmpty()) {            throw new IllegalArgumentException("队列为空");        }        return data[front];    }    private void resize(int capacity) {        E[] newData = (E[]) new Object[capacity + 1];        for (int i = 0; i < size; i++) {            newData[i] = data[(i + front) % data.length];        }        data = newData;        front = 0;        tail = size;    }    @Override    public String toString() {        StringBuilder res = new StringBuilder();        res.append(String.format("LoopQueue: size=%d , capacity=%d\n", size, getCapacity()));        res.append("Front: [");        for (int i = front; i != tail; i = (i + 1) % data.length) {            res.append(data[i]);            if ((i + 1) % data.length != tail)                res.append(',');        }        res.append("] tail");        return res.toString();    }    public static void main(String[] args){        LoopQueue
       
         queue = new LoopQueue<>(5);        for(int i = 0 ; i < 10 ; i ++){            queue.enqueue(i);            System.out.println(queue);            if(i % 3 == 2){                queue.dequeue();                System.out.println(queue);            }        }    }}