April 2024 - This site, and Kamaelia are being updated. There is significant work needed, and PRs are welcome.


Tags items with an incrementing sequence number

TagWithSequenceNumber tags items with a sequence numbers, for example: 0, 1, 2, 3, ... etc. The default initial value of the sequence is a 0.

It takes in items on its "inbox" inbox and outputs (seqnum, item) tuples on its "outbox" outbox.

Example Usage

Tagging frames from a Dirac video file with a frame number, starting with 1:

Pipeline( RateControlledFileReader("videofile.dirac", readmode="bytes", rate=... ),


At initialisation, specify the initial sequence number to use.

Send an item to TagWithSequenceNumber's "inbox" inbox, and it will send (seqnum, item) to its "outbox" outbox.

The sequence numbers begin 0, 1, 2, 3, ... etc ad infinitum.

If a producerFinished or shutdownMicroprocess message is received on the "control" inbox. It is immediately sent on out of the "signal" outbox and the component then immediately terminates.


class TagWithSequenceNumber(Axon.Component.component)

TagWithSequenceNumber() -> new TagWithSequenceNumber component.

Send 'item' to the "inbox" inbox and it will be tagged with a sequence number, and sent out as (seqnum, 'item') to the "outbox" outbox.

Sequence numbering goes 0, 1, 2, 3, ... etc.


  • control : Shutdown signalling
  • inbox : Items


  • outbox : Items tagged with a sequence number, in the form (seqnum, item)
  • signal : Shutdown signalling

Methods defined here


You should be using the inbox/outbox interface, not these methods (except construction). This documentation is designed as a roadmap as to their functionalilty for maintainers and new component developers.

__init__(self[, initial])


Main loop


Got a problem with the documentation? Something unclear that could be clearer? Want to help improve it? Constructive criticism is very welcome - especially if you can suggest a better rewording!

Please leave you feedback here in reply to the documentation thread in the Kamaelia blog.

-- Automatic documentation generator, 05 Jun 2009 at 03:01:38 UTC/GMT