apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/Replication/ReplicationRoundRobinServerGroup.cs

#if MYSQL_6_10

// Copyright ?2013, 2018, Oracle and/or its affiliates. All rights reserved.
//
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// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

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

namespace Externals.MySql.Data.MySqlClient.Replication
{
    /// <summary>
    /// Class that implements Round Robing Load Balancing technique.
    /// </summary>
    internal 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="isMaster">Flag indicating if the server to return must be a master.</param>
        /// <returns>A <see cref="ReplicationServer"/> object representing the next available server.</returns>
        internal protected override ReplicationServer GetServer(bool isMaster)
        {
            for (int i = 0; i < Servers.Count; i++)
            {
                nextServer++;
                if (nextServer == Servers.Count)
                    nextServer = 0;
                ReplicationServer s = Servers[nextServer];
                if (!s.IsAvailable) continue;
                if (isMaster && !s.IsMaster) continue;
                return s;
            }
            return null;
        }
    }
}

#endif