Interface CtsServices::MessageQueue

An interface for components which queue binary messages. A queue may be implemented using a transient or persistent storage mechanism, depending on the quality of service required by the user.

Operation Index

• dequeue
• enqueue
• failure
• newMessageId
• recover
• success

Operations

• dequeue

  Return the next message in the queue, and mark the message as being "in progress", so that subsequent calls to dequeue return subsequent messages. If the queue is empty, this call should block until a message is available.

      void dequeue
      (
          out CtsServices::MessageId id,
          out CtsServices::Message msg
      );
  

• enqueue

  Enqueue a binary message with an id that was previously generated by a call to newMessageId. Has no effect if this message id has already been enqueued, i.e. enqueue can be called multiple times with the same MessageId, and only the first such call has any effect.

      void enqueue
      (
          in CtsServices::MessageId id,
          in CtsServices::Message msg
      );
  

• failure

  Remove a message from the queue. This method will run in its own new transaction.

      void failure
      (
          in CtsServices::MessageId id,
          in string reason
      );
  

• newMessageId

  Generate a new, unique, MessageId that may be subsequently passed to enqueue.

      CtsServices::MessageId newMessageId
      (
      );
  

• recover

  Called on server startup to recover messages which were left in the "in progress" state from a previous run of the server. If the queue is transient (in memory), this call has no effect.

      void recover
      (
      );
  

• success

  Remove a message from the queue. This method will run in the same transaction as the user code which is invoked by processing the message (the user code is invoked first).

      void success
      (
          in CtsServices::MessageId id
      );