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using System;
using System.Collections.Generic;
using System.Text;

namespace MySql.Data.MySqlClient.Replication
{
  /// <summary>
  /// Class that implements Round Robing Load Balancing technique.
  /// </summary>
  public class ReplicationRoundRobinServerGroup : ReplicationServerGroup
  {
    private int nextServer;

    public ReplicationRoundRobinServerGroup(string name, int retryTime) : base(name, retryTime)
    {
      nextServer = -1;
    }

    /// <summary>
    /// Gets an available server based on Round Robin load balancing.
    /// </summary>
    /// <param name="isSource">Flag indicating if the server to return must be a source.</param>
    /// <returns>A <see cref="ReplicationServer"/> object representing the next available server.</returns>
    internal protected override ReplicationServer GetServer(bool isSource)
    {
      for (int i = 0; i < Servers.Count; i++)
      {
        nextServer++;
        if (nextServer == Servers.Count)
          nextServer = 0;
        ReplicationServer s = Servers[nextServer];
        if (!s.IsAvailable) continue;
        if (isSource && !s.IsSource) continue;
        return s;
      }
      return null;
    }
  }
}
