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


This module provides a set of components and convienience functions for making a CSA time out. To use it, simply call the function InactivityChassis with a timeout period and the CSA to wrap. This will send a producerFinished signal to the CSA if it does not send a message on its outbox or CreatorFeedback boxes before the timeout expires.


This component is a simple way of makinga timeout event occur. If it receives nothing after 5 seconds, a "NEXT" message is sent.

Example Usage

A tcp client that connects to a given host and port and prints and expects to receive something at more frequent than 5 seconds intervals. If it does not, it prints a rude message the first time this happens:

    TCPClient(HOST, PORT),
    PureTransformer(lambda x : "Oi, wake up. I have received nothing for 5 seconds!"),

More detail

By default, ResettableSender is set up to send a timeout message "NEXT" out of its "outbox" outbox within 5 seconds. However, if it receives any message on its "inbox" inbox then the timer is reset.

Once the timeout has occurred this component terminates. It will therefore only ever generate one "NEXT" message, even if multiple timeouts occur.

Termination is silent - no messages to indicate shutdown are sent out of the "signal" outbox. This component ignores any input on its "control" inbox - including shutdown messages.


ActivityMonitor monitors up to four streams of messages passing through it and, in response, sends messages out of its "observed" outbox to indicate that there has been activity.

This is intended to wrap a component such that it may be monitored by another component.

Example Usage

Type a line at the console, and your activity will be 'observed' - a 'RESET' message will appear as well as the line you have typed:

   MONITOR = ActivityMonitor(),
   OUTPUT  = ConsoleEchoer(),
   INPUT   = ConsoleReader(),
   linkages = {
       ("INPUT",   "outbox") : ("MONITOR", "inbox"),
       ("MONITOR", "outbox") : ("OUTPUT", "inbox"),

       ("MONITOR", "observed") : ("OUTPUT", "inbox"),


To use it, connect any of the three inboxes to outboxes on the component to be monitored.

The messages that are sent to those inboxes will be forwarded to their respective outbox. For example, suppose "HELLO" was received on 'inbox2'. self.message ("RESET" by default) will be sent on the 'observed' outbox and "HELLO" will be sent out on 'outbox2'.

ActivityMonitor will shut down upon receiving a producerFinished or shutdownCSA message on its control inbox.

Please note that this can't wrap adaptive components properly as of yet.

More detail

Any message sent to the "inbox", "inbox2", "inbox3" or "control" inboxes are immediately forwarded on out of the "outbox", "outbox2", "outbox3" or "signal" outboxes respectively.

Whenever this happens, a "RESET" message (the default) is sent out of the "observed" outbox.

For every batch of messages waiting at the three inboxes that get forwarded on out of their respective outboxes, only one "RESET" message will be sent. This should therefore only be used as a general indication of activity, not as a means of counting every individual message passing through this component.

Any message sent to the "control" inbox is also checked to see if it is a shutdownCSA or producerFinished message. If it is one of these then it will still be forwarded on out of the "signal" outbox, but will also cause ActivityMonitor to immediately terminate.

Any messages waiting at any of the inboxes (including the "control" inbox) at the time the shutdown triggering message is received will be sent on before termination.


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