数据库连接池Data Connection Framework

 

数据库连接池Data Connection Framework具备Connection pooling机制，能管理不同的ADO.net Connection。并通过池对象工厂去PoolObjectFactory去创建数据连接池。(可参考：对象工厂创建--- Singleton Object,SingleCall Object,Pool Object )

 

连接池企业应用组件图如下：

 

类图如下：

 

 主要文件代码：

 

  /// <summary>
    /// 连接池上下文
    /// </summary>
    public sealed class ConnectionPoolContext : IDisposable
    {
        /// <summary>
        /// 池对象工厂
        /// </summary>
        private PoolObjectFactory _factory;
        /// <summary>
        /// 默认连接字符
        /// </summary>
        private string _defaultConnectionString;
        /// <summary>
        /// 工厂名称
        /// </summary>
        private string _factoryName;
        /// <summary>
        /// 类型
        /// </summary>
        private Type _factoryType;
        /// <summary>
        /// SQL状态仓库
        /// </summary>
        private SqlStatementRepository _statementRepository;
        /// <summary>
        /// 连接池
        /// </summary>
        private static Dictionary<string, ConnectionPoolContext> _instances = new Dictionary<string, ConnectionPoolContext>();
        /// <summary>
        /// 默认连接字符属性
        /// </summary>
        public string DefaultConnectionString
        {
            get
            {
                return _defaultConnectionString;
            }
            set
            {
                _defaultConnectionString = value;
            }
        }
        /// <summary>
        /// 工厂名
        /// </summary>
        public string FactoryName
        {
            get
            {
                return _factoryName;
            }
            set
            {
                _factoryName = value;
            }
        }
        /// <summary>
        /// SQL状态仓库属性
        /// </summary>
        public SqlStatementRepository StatementRepository
        {
            get
            {
                if (_statementRepository == null)
                    _statementRepository = new SqlStatementRepository();
                return _statementRepository;
            }
        }
        /// <summary>
        /// 对象工厂模式
        /// </summary>
        internal PoolObjectFactory Factory
        {
            get
            {
                return _factory;
            }
            set
            {
                _factory = value;
            }
        }
        /// <summary>
        /// 实例化一个连接池
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static ConnectionPoolContext Instance(string id)
        {
            return _instances[id];
        }
        /// <summary>
        /// 添加一个连接到池中
        /// </summary>
        /// <param name="id">id</param>
        /// <param name="factoryName">工厂名称</param>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="max">最大数</param>
        /// <param name="limit">是否限制</param>
        public static void AddPool(string id, string factoryName, string connectionString, int max, bool limit)
        {
            ConnectionPoolContext p = new ConnectionPoolContext();
            p._defaultConnectionString = connectionString;
            p._factoryName = factoryName;
            p.Factory = new PoolObjectFactory(max, limit, new ArrayList());
            _instances.Add(id, p);
        }
        /// <summary>
        /// 得到一个连接
        /// </summary>
        /// <returns>数据库连接</returns>
        public DbConnection AcquireConnection()
        {
            if (_factoryType == null)
            {
                DbProviderFactory dbFactory = DbProviderFactories.GetFactory(_factoryName);
                DbConnection conn = dbFactory.CreateConnection();
                _factoryType = conn.GetType();
            }
            DbConnection connection = (DbConnection)Factory.AcquireObject(_factoryType);
            if (connection.ConnectionString == string.Empty)
                connection.ConnectionString = _defaultConnectionString;
            return connection;
        }
        /// <summary>
        /// 释放一个连接
        /// </summary>
        /// <param name="conn">数据库连接</param>
        public void ReleaseConnection(DbConnection conn)
        {
            Factory.ReleaseObject(conn);
            conn.Close();
        }

        #region IDisposable Members
        /// <summary>
        /// 释放连接
        /// </summary>
        public void Dispose()
        {
            if (_factory != null)
                ((IDisposable)_factory).Dispose();
        }

        #endregion
        /// <summary>
        /// 私有构造函数
        /// </summary>
        private ConnectionPoolContext()
        {
        }
    }

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