round-robin load balance algorithm C# demo

MyClass.cs

using System;
using System.Collections.Generic;
using RoundRobin;

public class MyClass
{
       public static void RunSnippet()
       {
              List<Node> servers = new List<Node>();
              servers.Add(new Node("serv","urlA",1));
              servers.Add(new Node("serv","urlB",1));
              servers.Add(new Node("serv","urlC",4));

              Dictionary<string,List<int>> dictLog = new Dictionary<string,List<int>>();

              RoundRobinBalancer balancer = new RoundRobinBalancer(servers);

              for(int i = 1;i<=100;i++){
                     Node node = balancer.DispatchTo();

                     if(!dictLog.ContainsKey(node.Url))
                           dictLog[node.Url] = new List<int>();
                     dictLog[node.Url].Add(i);
              }

              foreach(string key in dictLog.Keys){
                     WL("Url:{0} ==> {1}",key,dictLog[key].Count);
              }
       }

       #region Helper methods

       public static void Main()
       {
              try
              {
                     RunSnippet();
              }
              catch (Exception e)
              {
                     string error = string.Format("---\nThe following error occurred while executing the snippet:\n{0}\n---", e.ToString());
                     Console.WriteLine(error);
              }
              finally
              {
                     Console.Write("Press any key to continue...");
                     Console.ReadKey();
              }
       }

       private static void WL(object text, params object[] args)
       {
              Console.WriteLine(text.ToString(), args);
       }

       private static void RL()
       {
              Console.ReadLine();
       }

       private static void Break()
       {
              System.Diagnostics.Debugger.Break();
       }

       #endregion
}

namespace RoundRobin{

       public class Node{
              public Node(string serviceName,string url,int weight){
                     this.ServiceName = serviceName;
                     this.Url = url;
                     this.Weight = weight;
              }

              public int Weight{get;private set;}
              public string Url{get;private set;}
              public string ServiceName{get;private set;}
       }

       public class RoundRobinBalancer{
              private readonly List<Node> nodes;
              private int i = -1;
              private int cw = 0;

              public RoundRobinBalancer(List<Node> nodes){
                     this.nodes = nodes;
              }

              public Node DispatchTo(){
                     while(true){
                           i = (i+1)%nodes.Count;
                           if(i==0){
                                  cw = cw - MaxCommonDivisor(nodes);
                                  if(cw <= 0){
                                         cw = MaxWeight(nodes);
                                         if(cw == 0)
                                                return null;
                                  }
                           }
                           if((nodes[i]).Weight >= cw)
                                  return nodes[i];
                     }
              }

              private static int MaxCommonDivisor(List<Node> nodes){
                     List<int> nums = new List<int>();
                     foreach(Node node in nodes)
                     {
                           nums.Add(node.Weight);
                     }
                     return max_common_divisor(nums);
              }

              private static int MaxWeight(List<Node> nodes){
                     int ret = -1;
                     foreach(Node node in nodes){
                           if(node.Weight>ret)
                                  ret = node.Weight;
                     }
                     return ret;
              }

              public static int gcd(int n, int m)
              {
                     //swap
                     if (n<m)
                     {
                           n=m+n;
                           m=n-m;
                           n=n-m;
                     }
                     if (m==0) return n;
                     return gcd(m,n%m);
              }

              public static int max_common_divisor(List<int> several)
              {
                     int a=several[0];
                     int b=several[1];
                     int c=gcd(a,b);
                     int i;
                     for (i=2; i<several.Count; i++)
                     {
                           c=gcd(c,several[i]);
                     }
                     return c;
              }
       }
}