第五周作业 (作业一)

/**
 /**
 * @author zhuhuiming
 * @date 2020/10/25 3:51 下午
 * @description：
 * 整个组成部分：
 * 1、服务器ip集
 * 2、单个服务器ip对应的虚拟节点数
 * 3、虚拟节点和服务器ip映射关系集
 */
public class ConsistencyOperator {
    //单个服务器ip对应的虚拟节点数
    private static int virtual_num = 10;
    //虚拟节点和服务器ip映射关系集(其中key为hash值，value为对应的服务器ip)
    private final static TreeMap<Long,String> virtual_server_map = new TreeMap<>();
    private Set<String> server_ip = null;
    // 32位的 Fowler-Noll-Vo 哈希算法
    // https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function
    private static Long FNVHash(String key) {
        final int p = 16777619;
        Long hash = 2166136261L;
        for (int idx = 0, num = key.length(); idx < num; ++idx) {
            hash = (hash ^ key.charAt(idx)) * p;
        }
        hash += hash << 13;
        hash ^= hash >> 7;
        hash += hash << 3;
        hash ^= hash >> 17;
        hash += hash << 5;
        if (hash < 0) {
            hash = Math.abs(hash);
        }
        return hash;
    }
    //一个服务器ip对应虚拟节点个数
    public ConsistencyOperator(int virtual_num,Set<String> server_ip){
        if(virtual_num > 0)
        this.virtual_num = virtual_num;
        this.server_ip = server_ip;
        initVirtualServerNodes();
    }
    //生成虚拟节点
    private boolean initVirtualServerNodes(){
        Long hashcode = null;
        int size = server_ip.size();
        for(String ip:server_ip){
            for(int i = 0; i < virtual_num; i++){
                hashcode = FNVHash(ip+"#"+i);
                virtual_server_map.put(hashcode,ip);
            }
        }
        return true;
    }
    //加入服务节点
    public boolean addServerNode(String serverip){
        if(StringUtils.isBlank(serverip)) return false;
        server_ip.add(serverip);
        Long hashcode = null;
        for(int i = 0; i < virtual_num; i++){
            hashcode = FNVHash(serverip+"#"+i);
            virtual_server_map.put(hashcode,serverip);
        }
        return true;
    }
    //删除服务节点
    public boolean removeServerNode(String serverip){
        if(StringUtils.isBlank(serverip)) return false;
        server_ip.remove(serverip);
        Long hashcode = null;
        for(int i = 0; i < virtual_num; i++){
            hashcode = FNVHash(serverip+"#"+i);
            virtual_server_map.remove(hashcode);
        }
        return true;
    }
    // 查找对象映射的节点
    public String getObjectNode(String object) {
        long hash = FNVHash(object);
        SortedMap<Long, String> tailMap = virtual_server_map.tailMap(hash); // 所有大于 hash 的节点
        Long key = tailMap.isEmpty() ? virtual_server_map.firstKey() : tailMap.firstKey();
        return virtual_server_map.get(key);
    }
    // 统计对象与节点的映射关系
    public void dumpObjectNodeMap(String label, int objectMin, int objectMax) {
        // 统计
        Map<String, Integer> objectNodeMap = new TreeMap<>(); // IP => COUNT
        for (int object = objectMin; object <= objectMax; ++object) {
            String nodeIp = getObjectNode(Integer.toString(object));
            Integer count = objectNodeMap.get(nodeIp);
            objectNodeMap.put(nodeIp, (count == null ? 0 : count + 1));
        }
        // 打印
        double totalCount = objectMax - objectMin + 1;
        System.out.println("======== " + label + " ========");
        for (Map.Entry<String, Integer> entry : objectNodeMap.entrySet()) {
            long percent = (int) (100 * entry.getValue() / totalCount);
            System.out.println("IP=" + entry.getKey() + ": RATE=" + percent + "%");
        }
    }
    public static void main(String[] args) {
        Set<String> server_ip = new TreeSet<String>();
        //服务器ip地址集
        for(int i = 0; i < 10; i++){
            //写入10个server的ip
            server_ip.add("192.168.3."+i);
        }
        ConsistencyOperator ch = new ConsistencyOperator(100,server_ip);
        // 初始情况
        ch.dumpObjectNodeMap("初始情况", 0, 1000000);
    }
}