Java并发 -- Copy-on-Write模式

// 采用Immutability模式，每次上线、下线都创建新的Router对象或删除对应的Router对象
@Data
@AllArgsConstructor
public class Router {
    private final String ip;
    private final Integer port;
    private final String iFace;

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Router router = (Router) o;
        return Objects.equals(ip, router.ip) &&
                Objects.equals(port, router.port) &&
                Objects.equals(iFace, router.iFace);
    }

    @Override
    public int hashCode() {
        return Objects.hash(ip, port, iFace);
    }
}

class RouterTable {
    // <接口名 , 路由集合>
    private ConcurrentHashMap<String, CopyOnWriteArraySet<Router>> routingTable = new ConcurrentHashMap<>();

    // 获取路由
    public Set<Router> get(String iFace) {
        return routingTable.get(iFace);
    }

    // 增加路由
    public void add(Router router) {
        CopyOnWriteArraySet<Router> set = routingTable.computeIfAbsent(router.getIFace(),
                iFace -> new CopyOnWriteArraySet<>());
        set.add(router);
    }

    // 删除路由
    public void remove(Router router) {
        CopyOnWriteArraySet<Router> set = routingTable.get(router.getIFace());
        if (set != null) {
            set.remove(router);
        }
    }
}