Package org.lsst.ccs.messaging

Interface MessagingLayer

All Known Subinterfaces:
BusMessagingLayer
All Known Implementing Classes:
JGroupsBusMessagingLayer, JMSBusMessagingLayer
public interface MessagingLayer
Interface providing methods to connect/disconnect MessagingAccessLayer objects to/from the CCS buses and to send messages over the buses. An instance of a MessagingLayer is created via the MessagingManager. When connecting a MessagingAccessLayer, its name is used to uniquely identify it on the buses. If such name is not unique, a DuplicateAgentNameException is thrown.
Author:
emarin

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    connect(MessagingAccessLayer accessLayer)
    Connects a MessagingAccessLayer object on the buses by using its name as a unique identifier.
    void
    disconnect(MessagingAccessLayer accessLayer)
    Remove the entry point to the buses for the given MessagingAccessLayer.
    <T extends BusMessage>
    void
    sendMessage(String senderAgent, Bus bus, T msg, MessageFlag... flags)
    Sends a message on a bus for a given MessagingAccessLayer.

  • Method Details

    • sendMessage

      <T extends BusMessage> void sendMessage(String senderAgent, Bus bus, T msg, MessageFlag... flags)
      Sends a message on a bus for a given MessagingAccessLayer. The name of the MessagingAccessLayer determines the origin of the bus message. note : that BusMessage should have sender and destination information but it is not the role of the communication layer to parse destination information such as "subsystem1, subsystem2" or "subsystem3/module"a.
      Type Parameters:
      T - the type of message sent on the bus
      Parameters:
      senderAgent - provides the name as the origin of the message
      bus - the bus on which to send the message
      msg - the message
      flags - MessageFlag array associated to this message.
      Throws:
      RuntimeException - if the inner implementation fails sending the message

    • connect

      void connect(MessagingAccessLayer accessLayer) throws DuplicateAgentNameException, IOException
      Connects a MessagingAccessLayer object on the buses by using its name as a unique identifier. Upon creation, if needed, all needed buses are created. Depending on the underlying implementation, the MessagingLayer allows this method to be called more than once, or throws a RuntimeException. TBD : should all the buses be created or just the ones specified by the MessagingAccessLayer ?
      Parameters:
      accessLayer - The layer to be connected on the buses
      Throws:
      DuplicateAgentNameException - if the name of MessagingAccessLayer is not unique on the buses
      IOException

    • disconnect

      void disconnect(MessagingAccessLayer accessLayer)
      Remove the entry point to the buses for the given MessagingAccessLayer. At this point, the CCS buses might be closed.
      Parameters:
      accessLayer - The layer to be connected on the buses