mcs/class/Mono.Messaging.RabbitMQ/Mono.Messaging.RabbitMQ/RabbitMQMessageQueue.cs

   1 //
   2 // Mono.Messaging.RabbitMQ
   3 //
   4 // Authors:
   5 //        Michael Barker (mike@middlesoft.co.uk)
   6 //
   7 // (C) 2008 Michael Barker
   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 System;
  32 using System.Collections;
  33 using System.ComponentModel;
  34 using System.IO;
  35 using System.Text;
  36
  37 using RabbitMQ.Client;
  38 using RabbitMQ.Client.Content;
  39 using RabbitMQ.Client.Events;
  40 using RabbitMQ.Client.Exceptions;
  41 using RabbitMQ.Client.MessagePatterns;
  42 using RabbitMQ.Util;
  43
  44 namespace Mono.Messaging.RabbitMQ {
  45
  46         /// <summary>
  47         /// RabbitMQ Implementation of a message queue.  Currrently this implementation
  48         /// attempts to be as stateless as possible.  Connection the AMQP server
  49         /// are only created as needed.
  50         /// </summary>
  51         public class RabbitMQMessageQueue : MessageQueueBase, IMessageQueue {
  52
  53                 private bool authenticate = false;
  54                 private short basePriority = 0;
  55                 private Guid category = Guid.Empty;
  56                 private bool denySharedReceive = false;
  57                 private EncryptionRequired encryptionRequired;
  58                 private long maximumJournalSize = -1;
  59                 private long maximumQueueSize = -1;
  60                 private ISynchronizeInvoke synchronizingObject = null;
  61                 private bool useJournalQueue = false;
  62                 private QueueReference qRef = QueueReference.DEFAULT;
  63                 private readonly RabbitMQMessagingProvider provider;
  64                 private readonly MessageFactory helper;
  65                 private readonly string realm;
  66                 private readonly bool transactional;
  67
  68                 public RabbitMQMessageQueue (RabbitMQMessagingProvider provider,
  69                                              bool transactional)
  70                         : this (provider, QueueReference.DEFAULT, transactional)
  71                 {
  72                 }
  73
  74                 public RabbitMQMessageQueue (RabbitMQMessagingProvider provider,
  75                                              QueueReference qRef,
  76                                              bool transactional)
  77                         : this (provider, "/data", qRef, transactional)
  78                 {
  79                 }
  80
  81                 public RabbitMQMessageQueue (RabbitMQMessagingProvider provider,
  82                                              string realm, QueueReference qRef,
  83                                              bool transactional)
  84                 {
  85                         this.provider = provider;
  86                         this.helper = new MessageFactory (provider);
  87                         this.realm = realm;
  88                         this.qRef = qRef;
  89                         this.transactional = transactional;
  90                 }
  91
  92                 protected override IMessageQueue Queue {
  93                         get { return this; }
  94                 }
  95
  96                 public bool Authenticate {
  97                         get { return authenticate; }
  98                         set { authenticate = value; }
  99                 }
 100
 101                 public short BasePriority {
 102                         get { return basePriority; }
 103                         set { basePriority = value; }
 104                 }
 105
 106                 public bool CanRead {
 107                         get { throw new NotImplementedException (); }
 108                 }
 109
 110                 public bool CanWrite {
 111                         get { throw new NotImplementedException (); }
 112                 }
 113
 114                 public Guid Category {
 115                         get { return category; }
 116                         set { category = value; }
 117                 }
 118
 119                 public DateTime CreateTime {
 120                         get { throw new NotImplementedException (); }
 121                 }
 122
 123                 public bool DenySharedReceive {
 124                         get { return denySharedReceive; }
 125                         set { denySharedReceive = value; }
 126                 }
 127
 128                 public EncryptionRequired EncryptionRequired {
 129                         get { return encryptionRequired; }
 130                         set { encryptionRequired = value; }
 131                 }
 132
 133                 public Guid Id {
 134                         get { throw new NotImplementedException (); }
 135                 }
 136
 137                 public DateTime LastModifyTime {
 138                         get { throw new NotImplementedException (); }
 139                 }
 140
 141                 public long MaximumJournalSize {
 142                         get { return maximumJournalSize; }
 143                         set { maximumJournalSize = value; }
 144                 }
 145
 146                 public long MaximumQueueSize {
 147                         get { return maximumQueueSize; }
 148                         set { maximumQueueSize = value; }
 149                 }
 150
 151                 public IntPtr ReadHandle {
 152                         get { throw new NotImplementedException (); }
 153                 }
 154
 155                 public ISynchronizeInvoke SynchronizingObject {
 156                         get { return synchronizingObject; }
 157                         set { synchronizingObject = value; }
 158                 }
 159
 160                 public bool Transactional {
 161                         get { return transactional; }
 162                 }
 163
 164                 public bool UseJournalQueue {
 165                         get { return useJournalQueue; }
 166                         set { useJournalQueue = value; }
 167                 }
 168
 169                 public IntPtr WriteHandle {
 170                         get { throw new NotImplementedException (); }
 171                 }
 172
 173                 public QueueReference QRef {
 174                         get { return qRef; }
 175                         set { qRef = value; }
 176                 }
 177
 178                 private static long GetVersion (IConnection cn)
 179                 {
 180                         long version = cn.Protocol.MajorVersion;
 181                         version = version << 32;
 182                         version += cn.Protocol.MinorVersion;
 183                         return version;
 184                 }
 185
 186                 private void SetDeliveryInfo (IMessage msg, long senderVersion,
 187                                               string transactionId)
 188                 {
 189                         msg.SetDeliveryInfo (Acknowledgment.None,
 190                                              DateTime.MinValue,
 191                                              this,
 192                                              Guid.NewGuid ().ToString () + "\\0",
 193                                              MessageType.Normal,
 194                                              new byte[0],
 195                                              senderVersion,
 196                                              DateTime.UtcNow,
 197                                              null,
 198                                              transactionId);
 199                 }
 200
 201                 public void Close ()
 202                 {
 203                         // No-op (Queue are currently stateless)
 204                 }
 205
 206                 public static void Delete (string realm, QueueReference qRef)
 207                 {
 208                         ConnectionFactory cf = new ConnectionFactory ();
 209
 210                         using (IConnection cn = cf.CreateConnection (qRef.Host)) {
 211                                 using (IModel model = cn.CreateModel ()) {
 212                                         ushort ticket = model.AccessRequest (realm);
 213                                         model.QueueDelete (ticket, qRef.Queue, false, false, false);
 214                                 }
 215                         }
 216                 }
 217
 218                 public void Send (IMessage msg)
 219                 {
 220                         if (QRef == QueueReference.DEFAULT)
 221                                 throw new MonoMessagingException ("Path has not been specified");
 222
 223                         if (msg.BodyStream == null)
 224                                 throw new ArgumentException ("Message is not serialized properly");
 225
 226                         ConnectionFactory cf = new ConnectionFactory ();
 227
 228                         try {
 229                                 using (IConnection cn = cf.CreateConnection (QRef.Host)) {
 230                                         SetDeliveryInfo (msg, GetVersion (cn), null);
 231                                         using (IModel ch = cn.CreateModel ()) {
 232                                                 Send (ch, msg);
 233                                         }
 234                                 }
 235                         } catch (BrokerUnreachableException e) {
 236                                 throw new ConnectionException (QRef, e);
 237                         }
 238                 }
 239
 240                 public void Send (IMessage msg, IMessageQueueTransaction transaction)
 241                 {
 242                         if (QRef == QueueReference.DEFAULT)
 243                                 throw new MonoMessagingException ("Path has not been specified");
 244
 245                         if (msg.BodyStream == null)
 246                                 throw new ArgumentException ("Message is not serialized properly");
 247
 248                         RabbitMQMessageQueueTransaction tx = (RabbitMQMessageQueueTransaction) transaction;
 249
 250                         tx.RunSend (SendInContext, msg);
 251                 }
 252
 253                 public void Send (IMessage msg, MessageQueueTransactionType transactionType)
 254                 {
 255                         switch (transactionType) {
 256                         case MessageQueueTransactionType.Single:
 257                                 using (IMessageQueueTransaction tx = provider.CreateMessageQueueTransaction ()) {
 258                                         try {
 259                                                 Send (msg, tx);
 260                                                 tx.Commit ();
 261                                         } catch (Exception e) {
 262                                                 tx.Abort ();
 263                                                 throw new MonoMessagingException(e.Message, e);
 264                                         }
 265                                 }
 266                                 break;
 267
 268                         case MessageQueueTransactionType.None:
 269                                 Send (msg);
 270                                 break;
 271
 272                         case MessageQueueTransactionType.Automatic:
 273                                 throw new NotSupportedException("Automatic transaction types not supported");
 274                         }
 275                 }
 276
 277                 private void SendInContext (ref string host, ref IConnection cn,
 278                                             ref IModel model, IMessage msg, string txId)
 279                 {
 280                         if (host == null)
 281                                 host = QRef.Host;
 282                         else if (host != QRef.Host)
 283                                 throw new MonoMessagingException ("Transactions can not span multiple hosts");
 284
 285                         if (cn == null) {
 286                                 ConnectionFactory cf = new ConnectionFactory ();
 287                                 cn = cf.CreateConnection (host);
 288                         }
 289
 290                         if (model == null) {
 291                                 model = cn.CreateModel ();
 292                                 model.TxSelect ();
 293                         }
 294
 295                         SetDeliveryInfo (msg, GetVersion (cn), txId);
 296                         Send (model, msg);
 297                 }
 298
 299                 private void Send (IModel model, IMessage msg)
 300                 {
 301                         ushort ticket = model.AccessRequest ("/data");
 302                         string finalName = model.QueueDeclare (ticket, QRef.Queue, true);
 303                         IMessageBuilder mb = helper.WriteMessage (model, msg);
 304
 305                         model.BasicPublish (ticket, "", finalName,
 306                                             (IBasicProperties) mb.GetContentHeader(),
 307                                             mb.GetContentBody ());
 308                 }
 309
 310                 public void Purge ()
 311                 {
 312                         ConnectionFactory cf = new ConnectionFactory ();
 313
 314                         using (IConnection cn = cf.CreateConnection (QRef.Host)) {
 315                                 using (IModel model = cn.CreateModel ()) {
 316                                         ushort ticket = model.AccessRequest (realm);
 317                                         model.QueuePurge (ticket, QRef.Queue, false);
 318                                 }
 319                         }
 320                 }
 321
 322                 public IMessage Peek ()
 323                 {
 324                         ConnectionFactory cf = new ConnectionFactory ();
 325
 326                         using (IConnection cn = cf.CreateConnection (QRef.Host)) {
 327                                 using (IModel ch = cn.CreateModel ()) {
 328                                         return Receive (ch, -1, false);
 329                                 }
 330                         }
 331                 }
 332
 333                 public IMessage Peek (TimeSpan timeout)
 334                 {
 335                         return Run (Peeker (timeout));
 336                 }
 337
 338                 public IMessage PeekById (string id)
 339                 {
 340                         return Run (Peeker (ById (id)));
 341                 }
 342
 343                 public IMessage PeekById (string id, TimeSpan timeout)
 344                 {
 345                         return Run (Peeker (timeout, ById (id)));
 346                 }
 347
 348                 public IMessage PeekByCorrelationId (string id)
 349                 {
 350                         return Run (Peeker (ByCorrelationId (id)));
 351                 }
 352
 353                 public IMessage PeekByCorrelationId (string id, TimeSpan timeout)
 354                 {
 355                         return Run (Peeker (timeout, ByCorrelationId (id)));
 356                 }
 357
 358                 public IMessage Receive ()
 359                 {
 360                         return Run (Receiver ());
 361                 }
 362
 363                 public IMessage Receive (TimeSpan timeout)
 364                 {
 365                         return Run (Receiver (timeout));
 366                 }
 367
 368                 public IMessage Receive (TimeSpan timeout,
 369                                          IMessageQueueTransaction transaction)
 370                 {
 371                         return Run (transaction, Receiver (timeout));
 372                 }
 373
 374                 public IMessage Receive (TimeSpan timeout,
 375                                          MessageQueueTransactionType transactionType)
 376                 {
 377                         return Run (transactionType, Receiver (timeout));
 378                 }
 379
 380                 public IMessage Receive (IMessageQueueTransaction transaction)
 381                 {
 382                         return Run (transaction, Receiver());
 383                 }
 384
 385                 public IMessage Receive (MessageQueueTransactionType transactionType)
 386                 {
 387                         return Run (transactionType, Receiver ());
 388                 }
 389
 390                 public IMessage ReceiveById (string id)
 391                 {
 392                         return Run (Receiver (ById (id)));
 393                 }
 394
 395                 public IMessage ReceiveById (string id, TimeSpan timeout)
 396                 {
 397                         return Run (Receiver (timeout, ById (id)));
 398                 }
 399
 400                 public IMessage ReceiveById (string id,
 401                                              IMessageQueueTransaction transaction)
 402                 {
 403                         return Run (transaction, Receiver (ById (id)));
 404                 }
 405
 406                 public IMessage ReceiveById (string id,
 407                                              MessageQueueTransactionType transactionType)
 408                 {
 409                         return Run (transactionType, Receiver (ById (id)));
 410                 }
 411
 412                 public IMessage ReceiveById (string id, TimeSpan timeout,
 413                                              IMessageQueueTransaction transaction)
 414                 {
 415                         return Run (transaction, Receiver (timeout, ById (id)));
 416                 }
 417
 418                 public IMessage ReceiveById (string id, TimeSpan timeout,
 419                                              MessageQueueTransactionType transactionType)
 420                 {
 421                         return Run (transactionType, Receiver (timeout, ById (id)));
 422                 }
 423
 424                 public IMessage ReceiveByCorrelationId (string id)
 425                 {
 426                         return Run (Receiver (ByCorrelationId (id)));
 427                 }
 428
 429                 public IMessage ReceiveByCorrelationId (string id, TimeSpan timeout)
 430                 {
 431                         return Run (Receiver (timeout, ByCorrelationId (id)));
 432                 }
 433
 434                 public IMessage ReceiveByCorrelationId (string id,
 435                                                         IMessageQueueTransaction transaction)
 436                 {
 437                         return Run (transaction, Receiver (ByCorrelationId (id)));
 438                 }
 439
 440                 public IMessage ReceiveByCorrelationId (string id,
 441                                                         MessageQueueTransactionType transactionType)
 442                 {
 443                         return Run (transactionType, Receiver (ByCorrelationId (id)));
 444                 }
 445
 446                 public IMessage ReceiveByCorrelationId (string id, TimeSpan timeout,
 447                                                         IMessageQueueTransaction transaction)
 448                 {
 449                         return Run (transaction, Receiver (timeout, ByCorrelationId (id)));
 450                 }
 451
 452                 public IMessage ReceiveByCorrelationId (string id, TimeSpan timeout,
 453                                                         MessageQueueTransactionType transactionType)
 454                 {
 455                         return Run (transactionType, Receiver (timeout, ByCorrelationId (id)));
 456                 }
 457
 458                 public IMessageEnumerator GetMessageEnumerator ()
 459                 {
 460                         return new RabbitMQMessageEnumerator (helper, QRef);
 461                 }
 462
 463                 private IMessage Run (MessageQueueTransactionType transactionType,
 464                                       TxReceiver.DoReceive r)
 465                 {
 466                         switch (transactionType) {
 467                         case MessageQueueTransactionType.Single:
 468                                 using (RabbitMQMessageQueueTransaction tx = GetTx ()) {
 469                                         bool success = false;
 470                                         try {
 471                                                 IMessage msg = Run (tx, r);
 472                                                 tx.Commit ();
 473                                                 success = true;
 474                                                 return msg;
 475                                         } finally {
 476                                                 if (!success)
 477                                                         tx.Abort ();
 478                                         }
 479                                 }
 480
 481                         case MessageQueueTransactionType.None:
 482                                 return Run (r);
 483
 484                         default:
 485                                 throw new NotSupportedException(transactionType + " not supported");
 486                         }
 487                 }
 488
 489                 private IMessage Run (IMessageQueueTransaction transaction,
 490                                       TxReceiver.DoReceive r)
 491                 {
 492                         TxReceiver txr = new TxReceiver (this, r);
 493                         RabbitMQMessageQueueTransaction tx =
 494                                 (RabbitMQMessageQueueTransaction) transaction;
 495                         return tx.RunReceive (txr.ReceiveInContext);
 496                 }
 497
 498                 private IMessage Run (TxReceiver.DoReceive r)
 499                 {
 500                         ConnectionFactory cf = new ConnectionFactory ();
 501                         using (IConnection cn = cf.CreateConnection (QRef.Host)) {
 502                                 using (IModel model = cn.CreateModel ()) {
 503                                         return r (this, model);
 504                                 }
 505                         }
 506                 }
 507
 508                 private IMessage ReceiveInContext (ref string host, ref IConnection cn,
 509                                                    ref IModel model, string txId)
 510                 {
 511                         if (host == null)
 512                                 host = QRef.Host;
 513                         else if (host != QRef.Host)
 514                                 throw new MonoMessagingException ("Transactions can not span multiple hosts");
 515
 516                         if (cn == null) {
 517                                 ConnectionFactory cf = new ConnectionFactory ();
 518                                 cn = cf.CreateConnection (host);
 519                         }
 520
 521                         if (model == null) {
 522                                 model = cn.CreateModel ();
 523                                 model.TxSelect ();
 524                         }
 525
 526                         return Receive (model, -1, true);
 527                 }
 528
 529                 private class TxReceiver
 530                 {
 531                         private readonly DoReceive doReceive;
 532                         private readonly RabbitMQMessageQueue q;
 533
 534                         public TxReceiver(RabbitMQMessageQueue q, DoReceive doReceive) {
 535                                 this.q = q;
 536                                 this.doReceive = doReceive;
 537                         }
 538
 539                         public delegate IMessage DoReceive (RabbitMQMessageQueue q, IModel model);
 540
 541                         public IMessage ReceiveInContext (ref string host, ref IConnection cn,
 542                                                           ref IModel model, string txId)
 543                         {
 544                                 if (host == null)
 545                                         host = q.QRef.Host;
 546                                 else if (host != q.QRef.Host)
 547                                         throw new MonoMessagingException ("Transactions can not span multiple hosts");
 548
 549                                 if (cn == null) {
 550                                         ConnectionFactory cf = new ConnectionFactory ();
 551                                         cn = cf.CreateConnection (host);
 552                                 }
 553
 554                                 if (model == null) {
 555                                         model = cn.CreateModel ();
 556                                         model.TxSelect ();
 557                                 }
 558
 559                                 return doReceive (q, model);
 560                         }
 561                 }
 562
 563                 private class DoReceiveWithTimeout
 564                 {
 565                         private readonly int timeout;
 566                         private readonly IsMatch matcher;
 567                         private readonly bool ack;
 568
 569                         public DoReceiveWithTimeout (int timeout, IsMatch matcher)
 570                                 : this (timeout, matcher, true)
 571                         {
 572                         }
 573
 574                         public DoReceiveWithTimeout (int timeout, IsMatch matcher, bool ack)
 575                         {
 576                                 if (matcher != null && timeout == -1)
 577                                         this.timeout = 500;
 578                                 else
 579                                         this.timeout = timeout;
 580                                 this.matcher = matcher;
 581                                 this.ack = ack;
 582                         }
 583
 584                         public IMessage DoReceive (RabbitMQMessageQueue q, IModel model)
 585                         {
 586                                 if (matcher == null)
 587                                         return q.Receive (model, timeout, ack);
 588                                 else
 589                                         return q.Receive (model, timeout, ack, matcher);
 590                         }
 591                 }
 592
 593                 private static TxReceiver.DoReceive Receiver (TimeSpan timeout,
 594                                                               IsMatch matcher)
 595                 {
 596                         int to = TimeSpanToInt32 (timeout);
 597                         return new DoReceiveWithTimeout (to, matcher).DoReceive;
 598                 }
 599
 600                 private static TxReceiver.DoReceive Receiver (IsMatch matcher)
 601                 {
 602                         return new DoReceiveWithTimeout (-1, matcher).DoReceive;
 603                 }
 604
 605                 private static TxReceiver.DoReceive Receiver (TimeSpan timeout)
 606                 {
 607                         int to = TimeSpanToInt32 (timeout);
 608                         return new DoReceiveWithTimeout (to, null).DoReceive;
 609                 }
 610
 611                 private TxReceiver.DoReceive Receiver ()
 612                 {
 613                         return new DoReceiveWithTimeout (-1, null).DoReceive;
 614                 }
 615
 616                 private TxReceiver.DoReceive Peeker ()
 617                 {
 618                         return new DoReceiveWithTimeout (-1, null).DoReceive;
 619                 }
 620
 621                 private TxReceiver.DoReceive Peeker (TimeSpan timeout)
 622                 {
 623                         int to = TimeSpanToInt32 (timeout);
 624                         return new DoReceiveWithTimeout (to, null, false).DoReceive;
 625                 }
 626
 627                 private TxReceiver.DoReceive Peeker (IsMatch matcher)
 628                 {
 629                         return new DoReceiveWithTimeout (-1, matcher, false).DoReceive;
 630                 }
 631
 632                 private TxReceiver.DoReceive Peeker (TimeSpan timeout, IsMatch matcher)
 633                 {
 634                         int to = TimeSpanToInt32 (timeout);
 635                         return new DoReceiveWithTimeout (to, matcher, false).DoReceive;
 636                 }
 637
 638                 delegate bool IsMatch (BasicDeliverEventArgs result);
 639
 640                 private class IdMatcher
 641                 {
 642                         private readonly string id;
 643                         public IdMatcher (string id)
 644                         {
 645                                 this.id = id;
 646                         }
 647
 648                         public bool MatchById (BasicDeliverEventArgs result)
 649                         {
 650                                 return result.BasicProperties.MessageId == id;
 651                         }
 652                 }
 653
 654                 private static IsMatch ById (string id)
 655                 {
 656                         return new IdMatcher (id).MatchById;
 657                 }
 658
 659                 private class CorrelationIdMatcher
 660                 {
 661                         private readonly string correlationId;
 662                         public CorrelationIdMatcher (string correlationId)
 663                         {
 664                                 this.correlationId = correlationId;
 665                         }
 666
 667                         public bool MatchById (BasicDeliverEventArgs result)
 668                         {
 669                                 return result.BasicProperties.CorrelationId == correlationId;
 670                         }
 671                 }
 672
 673                 private static IsMatch ByCorrelationId (string correlationId)
 674                 {
 675                         return new CorrelationIdMatcher (correlationId).MatchById;
 676                 }
 677
 678                 private IMessage Receive (IModel model, int timeout, bool doAck)
 679                 {
 680                         ushort ticket = model.AccessRequest (realm);
 681                         string finalName = model.QueueDeclare (ticket, QRef.Queue, false);
 682
 683                         using (Subscription sub = new Subscription (model, ticket, finalName)) {
 684                                 BasicDeliverEventArgs result;
 685                                 if (sub.Next (timeout, out result)) {
 686                                         IMessage m = helper.ReadMessage (QRef, result);
 687                                         if (doAck)
 688                                                 sub.Ack (result);
 689                                         return m;
 690                                 } else {
 691                                         throw new MonoMessagingException ("No Message Available");
 692                                 }
 693                         }
 694                 }
 695
 696                 private IMessage Receive (IModel model, int timeout,
 697                                           bool doAck, IsMatch matcher)
 698                 {
 699                         ushort ticket = model.AccessRequest (realm);
 700                         string finalName = model.QueueDeclare (ticket, QRef.Queue, false);
 701
 702                         using (Subscription sub = new Subscription (model, ticket, finalName)) {
 703                                 BasicDeliverEventArgs result;
 704                                 while (sub.Next (timeout, out result)) {
 705
 706                                         if (matcher (result)) {
 707                                                 IMessage m = helper.ReadMessage (QRef, result);
 708                                                 if (doAck)
 709                                                         sub.Ack (result);
 710                                                 return m;
 711                                         }
 712                                 }
 713
 714                                 throw new MessageUnavailableException ("Message not available");
 715                         }
 716                 }
 717
 718                 private RabbitMQMessageQueueTransaction GetTx ()
 719                 {
 720                         return (RabbitMQMessageQueueTransaction) provider.CreateMessageQueueTransaction ();
 721                 }
 722
 723                 private static int TimeSpanToInt32 (TimeSpan timespan)
 724                 {
 725                         if (timespan == TimeSpan.MaxValue)
 726                                 return -1;
 727                         else
 728                                 return (int) timespan.TotalMilliseconds;
 729                 }
 730         }
 731 }