Java PriorityQueue自定义比较器

Question

在我的PriorityQueue中，我有两种类型的客户，即VIP和常规客户。我想先为贵宾服务，再为常客服务。

如果CustomerID<100，则视为VIP。

如果客户是VIP，他会排在队列中VIP部分的最后

public class Order implements Comparable<Order> {
    private final int customerID;
    private final int amount;
    private final boolean vip_status;

    public Order(int customerID, int amount) { 
        this.customerID = customerID;
        this.amount = amount;
        this.vip_status = customerID < 100 ? true : false;

    }

    @Override
    public int compareTo(Order o) {
        if (vip_status && !o.vip_status) {
            return -1;
        }
        if (!vip_status && o.vip_status)
            return 1;
        return 0;
    }

    public int getCustomerID() {
        return customerID;
    }

    public int getAmount() {
        return amount;
    }

    public boolean isVip_status() {
        return vip_status;
    }
}

import java.util.PriorityQueue;

public class MyPriorityQueue {
    public static void main(String[] args) {
        PriorityQueue<Order> queue = new PriorityQueue<>();
        Order o1 = new Order(1, 50);
        Order o2 = new Order(5, 30);
        Order o3 = new Order(4, 10);
        Order o4 = new Order(150, 5);
        Order o5 = new Order(2, 5);
        Order o6 = new Order(200, 5);

        queue.add(o1);
        queue.add(o2);
        queue.add(o3);
        queue.add(o4);
        queue.add(o5);
        queue.add(o6);

        while(!queue.isEmpty()){
            Order s = queue.poll();
            System.out.printf("VIP Status: %s CustomerID: %s Amount: %s%n", 
                        s.isVip_status(), s.getCustomerID(), s.getAmount());
        }
    }
}

VIP Status: true CustomerID: 1 Amount: 50
VIP Status: true CustomerID: 5 Amount: 30
VIP Status: true CustomerID: 2 Amount: 5
VIP Status: true CustomerID: 4 Amount: 10
VIP Status: false CustomerID: 150 Amount: 5
VIP Status: false CustomerID: 200 Amount: 5

VIP Status: true CustomerID: 1 Amount: 50
VIP Status: true CustomerID: 5 Amount: 30
VIP Status: true CustomerID: 4 Amount: 10
VIP Status: true CustomerID: 2 Amount: 5
VIP Status: false CustomerID: 150 Amount: 5
VIP Status: false CustomerID: 200 Amount: 5

更新：我不想排序任何其他列除了VIP。我不想添加“日期”，因为它感觉像是一个黑客，而不是理解Java是如何工作的。

Answer 1

看起来java自带的priorityqueue类可以自由地重新排序项目，如果它们彼此比较相等。

^{（这不是“java如何工作”，它只是代表java运行时附带的某个类的一点错误。）}

所以，这里有一些可能会起作用的东西：

@Override
public int compareTo( OrderPlacement o ) 
{
    int d = -Boolean.compare( order.vip_status, o.order.vip_status );
    if( d != 0 )
        return d;
    return Integer.compare( priority, o.priority );
}