C# 中应用

要使用 C# 实现一个集群，首先初始化一个 Cluster 节点数组并将其传递给 ClusterDatabase.Open() 方法，然后为该数据库实例化一个 ClusterConnection 并创建一个监听线程。最后调用 ClusterConnection.Stop() 方法来终止集群会话。以下代码片段演示了一个简单的 C# 集群应用程序如何执行这些步骤：

    public class Cluster
    {
        Database db;
        // listen thread
        public void ClusterListen() 
        {
            ClusterConnection con = new ClusterConnection(db);
            con.Listen();
            
            con.Disconnect();
        }
     
        public static long msec()
        {
            return DateTime.Now.Ticks / 10000;
        }
     
        private bool checkQuorum(int[] neighbourIds)
        {
            Console.Write("Checking quorum. Neighbours are:");
            foreach (int nid in neighbourIds) 
            {
                Console.Write("{0} ", nid);
            }
            Console.WriteLine("Return {0}", true);
            return true;
        }
         
        public bool CheckFunc(int[] neighbourIds) // for delegate call
        {
            bool result = true;
            // logic to determine if nodes can access my_data
            return result;
        }
     
        public static void Main(String[] args)
        {
            new Cluster(Int32.Parse(args[0]), Int32.Parse(args[1]));
        }
     
        Cluster(int n_nodes, int node_id)
        {
            Database.Parameters parameters = new Database.Parameters();
            parameters.MemPageSize = PAGE_SIZE;
            parameters.Classes = new Type[]{typeof(Record)};
            Database.ClusterNodeParams[] node_params = new
            Database.ClusterNodeParams[n_nodes];
         
            for (int i = 0; i < n_nodes; ++i) 
            {
                //use different ports on the localhost
                node_params[i].Addr = "127.0.0.1:200" + (10 + i * 10);
                node_params[i].QRank = 1;
            }
         
            // set cluster parameters - nodes and window length
            parameters.ClusterParameters = new Database.ClusterParams( node_params,
            
                                            node_id );
            
            parameters.ClusterParameters.Window.Length = WINDOW_LENGTH;
     
            // create delegate and assign the member function
            CheckQuorum checkQ = new CheckQuorum();
            checkQ.my_data = 119; // set user context
            parameters.ClusterParameters.QuorumDelegate = new
            Database.ClusterQuorumDelegate(checkQ.CheckFunc);
         
            db = new Database(new ExtremedbWrapper(), Database.Mode.ClusterSupport);
            
            db.Open("cluster-db", parameters, DATABASE_SIZE);
            
         
            //start cluster listener thread
            Thread listenThread = new Thread(new ThreadStart(ClusterListen));
            listenThread.Start();
            // connect to the database using ClusterConnection
         
            ClusterConnection con = new ClusterConnection(db);
            
            // do operations on the database
     
            con.Stop(); // stop cluster runtime. Returns after ALL nodes call Stop()
            listenThread.Join();  // wait for listener thread
         
            con.Disconnect();
            db.Close();
        }
    }

请注意，集群运行时在数据库构造函数中启动。还要注意使用了 CheckQuorum 委托，它允许应用程序在线验证节点集合，以确定集群是否可以开始处理。