queue.java

package com.company;

import java.util.Date;
import java.util.List;
import java.util.Optional;

public class Main {

    public static void main(String[] args) {
        Queue queue = new Queue(3);
        queue.enqueueClient(1);
        queue.enqueueClient(2);
        queue.enqueueClient(3);

        Optional<QueueClient> queueClient = queue.queryInfo(2);
        QueueClient client = queueClient.get();
        System.out.println("Position of clientId = " + client.id + ", position = " + client.position);

        queue.dequeueClients(2);

        queueClient = queue.queryInfo(3);
        client = queueClient.get();
        System.out.println("Position of clientId = " + client.id + ", position = " + client.position);
    }

    static class QueueClient {
        private long id;
        private long position;
        private Date enqueueTimestamp;
        private long waitingSeconds;

        public QueueClient(long id, long position, Date enqueueTimestamp, long waitingSeconds) {
            this.id = id;
            this.position = position;
            this.enqueueTimestamp = enqueueTimestamp;
            this.waitingSeconds = waitingSeconds;
        }

        public long getPosition() {
            return position;
        }

        public void setPosition(long position) {
            this.position = position;
        }

        public Date getEnqueueTimestamp() {
            return enqueueTimestamp;
        }

        public void setEnqueueTimestamp(Date enqueueTimestamp) {
            this.enqueueTimestamp = enqueueTimestamp;
        }

        public long getId() {
            return id;
        }

        public void setId(long id) {
            this.id = id;
        }

        public long getWaitingSeconds() {
            return waitingSeconds;
        }

        public void setWaitingSeconds(long waitingSeconds) {
            this.waitingSeconds = waitingSeconds;
        }
    }

    static class Queue {
        private long capacity;

        public Queue(long capacity) {
            // write your code here
        }

        /***
         * 输入 clientId，返回 client 排队结果。
         * 如果 queue 中没有空余位置，返回 Optional.empty()。
         */
        public Optional<QueueClient> enqueueClient(long clientId) {
            // write your code here
            return Optional.empty();
        }

        /***
         * 输入 clientId，查询 client 排队情况，QueueClient.waitingSecond 表示在队列中已经等待的时长。
         * 如果该 clientId 没有在队列中，返回 Optional.empty()。
         */
        public Optional<QueueClient> queryInfo(long clientId) {
            // write your code here
            return Optional.empty();
        }

        /***
         * 将排在队首的 number 个 client 出队，QueueClient.waitingSecond 表示在队列中已经等待的时长。
         */
        public List<QueueClient> dequeueClients(long number) {
            // write your code here
            return List.of();
        }
    }
}