mcs/class/Mono.Data.Tds/Mono.Data.Tds.Protocol/TdsConnectionPool.cs

   1 //
   2 // Mono.Data.TdsClient.TdsConnectionPool.cs
   3 //
   4 // Author:
   5 //   Lluis Sanchez Gual (lluis@ximian.com)
   6 //
   7 // Copyright (C) 2004 Novell, Inc.
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using Mono.Data.Tds.Protocol;
  32 using System;
  33 using System.Collections;
  34 using System.Threading;
  35
  36 namespace Mono.Data.Tds.Protocol
  37 {
  38         public class TdsConnectionPoolManager
  39         {
  40                 Hashtable pools = new Hashtable ();
  41                 TdsVersion version;
  42
  43                 public TdsConnectionPoolManager (TdsVersion version)
  44                 {
  45                         this.version = version;
  46                 }
  47
  48                 public TdsConnectionPool GetConnectionPool (string connectionString, TdsConnectionInfo info)
  49                 {
  50                         lock (pools)
  51                         {
  52                                 TdsConnectionPool pool = (TdsConnectionPool) pools [connectionString];
  53                                 if (pool == null) {
  54                                         pool = new TdsConnectionPool (this, info);
  55                                         pools [connectionString] = pool;
  56                                 }
  57                                 return pool;
  58                         }
  59                 }
  60
  61                 public virtual ITds CreateConnection (TdsConnectionInfo info)
  62                 {
  63                         switch (version)
  64                         {
  65                                 case TdsVersion.tds42:
  66                                         return new Tds42 (info.DataSource, info.Port, info.PacketSize, info.Timeout);
  67                                 case TdsVersion.tds50:
  68                                         return new Tds50 (info.DataSource, info.Port, info.PacketSize, info.Timeout);
  69                                 case TdsVersion.tds70:
  70                                         return new Tds70 (info.DataSource, info.Port, info.PacketSize, info.Timeout);
  71                                 case TdsVersion.tds80:
  72                                         return new Tds80 (info.DataSource, info.Port, info.PacketSize, info.Timeout);
  73                         }
  74                         throw new NotSupportedException ();
  75                 }
  76         }
  77
  78         public class TdsConnectionInfo
  79         {
  80                 public TdsConnectionInfo (string dataSource, int port, int packetSize, int timeout, int minSize, int maxSize)
  81                 {
  82                         DataSource = dataSource;
  83                         Port = port;
  84                         PacketSize = packetSize;
  85                         Timeout = timeout;
  86                         PoolMinSize = minSize;
  87                         PoolMaxSize = maxSize;
  88                 }
  89
  90                 public string DataSource;
  91                 public int Port;
  92                 public int PacketSize;
  93                 public int Timeout;
  94                 public int PoolMinSize;
  95                 public int PoolMaxSize;
  96         }
  97
  98         public class TdsConnectionPool
  99         {
 100                 ArrayList list = new ArrayList ();
 101                 TdsConnectionInfo info;
 102                 bool initialized;
 103                 int activeConnections = 0;
 104                 TdsConnectionPoolManager manager;
 105
 106                 public TdsConnectionPool (TdsConnectionPoolManager manager, TdsConnectionInfo info)
 107                 {
 108                         this.info = info;
 109                         this.manager = manager;
 110                 }
 111
 112                 #region Methods
 113
 114                 public ITds GetConnection ()
 115                 {
 116                         ITds connection = null;
 117
 118                         lock (list)
 119                         {
 120                                 if (!initialized)
 121                                 {
 122                                         for (int n=0; n<info.PoolMinSize; n++)
 123                                                 list.Add (CreateConnection ());
 124                                         initialized = true;
 125                                 }
 126
 127                                 do {
 128                                         if (list.Count > 0)
 129                                         {
 130                                                 // There are available connections
 131                                                 connection = (ITds) list [list.Count - 1];
 132                                                 list.RemoveAt (list.Count - 1);
 133                                                 if (!connection.Reset ()) {
 134                                                         try {
 135                                                                 connection.Disconnect ();
 136                                                         } catch {}
 137                                                         connection = null;
 138                                                         continue;
 139                                                 }
 140                                         }
 141
 142                                         if (connection == null && activeConnections < info.PoolMaxSize)
 143                                         {
 144                                                 // No connections available, but the connection limit
 145                                                 // has not been reached yet, so a new one can be created
 146                                                 connection = CreateConnection();
 147                                         }
 148
 149                                         // No available connections in the pool
 150                                         // Wait for somewone to release one.
 151                                         if (connection == null)
 152                                         {
 153                                                 Monitor.Wait (list);
 154                                         }
 155                                 }
 156                                 while (connection == null);
 157                         }
 158
 159                         return connection;
 160                 }
 161
 162                 public void ReleaseConnection (ITds tds)
 163                 {
 164                         lock (list)
 165                         {
 166                                 list.Add (tds);
 167                                 Monitor.Pulse (list);
 168                         }
 169                 }
 170
 171                 ITds CreateConnection ()
 172                 {
 173                         activeConnections++;
 174                         return manager.CreateConnection (info);
 175                 }
 176
 177                 #endregion // Methods
 178         }
 179 }