private void EnsureMessagingEntityExists(MessageTypeMessagingEntityMappingDetails mappingDetails, IEnumerable <MessageTypeMessagingEntityMappingDetails> allMessageTypePathMappings) { MessagingEntityCreationOptions creationOptions = mappingDetails.CreationOptions; if (creationOptions != MessagingEntityCreationOptions.None && !_verifiedExistingMessagingEntities.Contains(mappingDetails)) { Func <bool> exists; Action create; Action delete; string path = mappingDetails.Path; switch (mappingDetails.MessagingEntityType) { case MessagingEntityType.Queue: exists = () => _namespaceManager.QueueExists(path); create = () => _namespaceManager.CreateQueue(path); delete = () => _namespaceManager.DeleteQueue(path); break; case MessagingEntityType.Topic: exists = () => _namespaceManager.TopicExists(path); create = () => _namespaceManager.CreateTopic(path); delete = () => _namespaceManager.DeleteTopic(path); break; case MessagingEntityType.Subscription: string[] parts = path.Split('/'); string topicPath = parts[0]; string subscriptionName = parts[2]; exists = () => _namespaceManager.SubscriptionExists(topicPath, subscriptionName); create = () => { MessageTypeMessagingEntityMappingDetails topicMessageTypePathMapping = allMessageTypePathMappings.FirstOrDefault(mtpmd => mtpmd.MessagingEntityType == MessagingEntityType.Topic && mtpmd.Path == topicPath); if (topicMessageTypePathMapping == null) { topicMessageTypePathMapping = new MessageTypeMessagingEntityMappingDetails(mappingDetails.MessageType, topicPath, MessagingEntityType.Topic, MessagingEntityCreationOptions.VerifyAlreadyExists); } EnsureMessagingEntityExists(topicMessageTypePathMapping, allMessageTypePathMappings); _namespaceManager.CreateSubscription(topicPath, subscriptionName); }; delete = () => _namespaceManager.DeleteSubscription(topicPath, subscriptionName); break; default: throw new NotSupportedException(string.Format("Unsupported messaging entity type, {0}, requested for creation (path {1}).", mappingDetails.MessagingEntityType, mappingDetails.Path)); } bool alreadyExists = exists(); if (alreadyExists) { if ((creationOptions & MessagingEntityCreationOptions.CreateAsTemporary) != 0) { if ((creationOptions & MessagingEntityCreationOptions.RecreateExistingTemporary) == 0) { throw new MessagingEntityAlreadyExistsException(mappingDetails.Path, mappingDetails.MessagingEntityType); } try { delete(); alreadyExists = false; } catch (UnauthorizedAccessException exception) { throw new UnauthorizedAccessException(string.Format("Unable to delete temporary messaging that already exists at path \"{0}\" due to insufficient access. Make sure the policy being used has 'Manage' permission for the namespace.", mappingDetails.Path), exception); } } } if (!alreadyExists) { if ((creationOptions & (MessagingEntityCreationOptions.CreateIfDoesntExist | MessagingEntityCreationOptions.CreateAsTemporary)) == 0) { throw new MessagingEntityDoesNotAlreadyExistException(mappingDetails.Path, mappingDetails.MessagingEntityType); } try { create(); } catch (UnauthorizedAccessException exception) { throw new UnauthorizedAccessException(string.Format("Unable to create messaging entity at path \"{0}\" due to insufficient access. Make sure the policy being used has 'Manage' permission for the namespace.", mappingDetails.Path), exception); } } _verifiedExistingMessagingEntities.Add(mappingDetails); } }