資料庫連接池Data Connection Framework

 

資料庫連接池Data Connection Framework具備Connection pooling機制，能管理不同的ADO.net Connection。並通過池對象工廠去PoolObjectFactory去建立資料連線池。(可參考：對象工廠建立--- Singleton Object,SingleCall Object,Pool Object )

 

串連池公司專屬應用程式元件圖表如下：

 

類圖如下：

 

 主要檔案代碼：

 

  /// <summary>
    /// 串連池上下文
    /// </summary>
    public sealed class ConnectionPoolContext : IDisposable
    {
        /// <summary>
        /// 池對象工廠
        /// </summary>
        private PoolObjectFactory _factory;
        /// <summary>
        /// 預設串連字元
        /// </summary>
        private string _defaultConnectionString;
        /// <summary>
        /// 工廠名稱
        /// </summary>
        private string _factoryName;
        /// <summary>
        /// 類型
        /// </summary>
        private Type _factoryType;
        /// <summary>
        /// SQL狀態倉庫
        /// </summary>
        private SqlStatementRepository _statementRepository;
        /// <summary>
        /// 串連池
        /// </summary>
        private static Dictionary<string, ConnectionPoolContext> _instances = new Dictionary<string, ConnectionPoolContext>();
        /// <summary>
        /// 預設串連字元屬性
        /// </summary>
        public string DefaultConnectionString
        {
            get
            {
                return _defaultConnectionString;
            }
            set
            {
                _defaultConnectionString = value;
            }
        }
        /// <summary>
        /// 工廠名
        /// </summary>
        public string FactoryName
        {
            get
            {
                return _factoryName;
            }
            set
            {
                _factoryName = value;
            }
        }
        /// <summary>
        /// SQL狀態倉庫屬性
        /// </summary>
        public SqlStatementRepository StatementRepository
        {
            get
            {
                if (_statementRepository == null)
                    _statementRepository = new SqlStatementRepository();
                return _statementRepository;
            }
        }
        /// <summary>
        /// 對象原廠模式
        /// </summary>
        internal PoolObjectFactory Factory
        {
            get
            {
                return _factory;
            }
            set
            {
                _factory = value;
            }
        }
        /// <summary>
        /// 執行個體化一個串連池
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static ConnectionPoolContext Instance(string id)
        {
            return _instances[id];
        }
        /// <summary>
        /// 添加一個串連到池中
        /// </summary>
        /// <param name="id">id</param>
        /// <param name="factoryName">工廠名稱</param>
        /// <param name="connectionString">連接字串</param>
        /// <param name="max">最大數</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>
        /// 得到一個串連
        /// </summary>
        /// <returns>資料庫連接</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>
        /// 釋放一個串連
        /// </summary>
        /// <param name="conn">資料庫連接</param>
        public void ReleaseConnection(DbConnection conn)
        {
            Factory.ReleaseObject(conn);
            conn.Close();
        }

        #region IDisposable Members
        /// <summary>
        /// 釋放串連
        /// </summary>
        public void Dispose()
        {
            if (_factory != null)
                ((IDisposable)_factory).Dispose();
        }

        #endregion
        /// <summary>
        /// 私人建構函式
        /// </summary>
        private ConnectionPoolContext()
        {
        }
    }

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