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//
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// See the GNU General Public License, version 2.0, for more details.
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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)
        {
            this.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 < this.Servers.Count; i++)
            {
                this.nextServer++;
                if (this.nextServer == this.Servers.Count)
                {
                    this.nextServer = 0;
                }

                ReplicationServer s = this.Servers[this.nextServer];
                if (!s.IsAvailable)
                {
                    continue;
                }

                if (isSource && !s.IsSource)
                {
                    continue;
                }

                return s;
            }

            return null;
        }
    }
}