Class FD_SIMPLE


  • public class FD_SIMPLE
    extends Protocol
    Simple failure detection protocol. Periodically sends a are-you-alive message to a randomly chosen member (excluding itself) and waits for a response. If a response has not been received within timeout msecs, a counter associated with that member will be incremented. If the counter exceeds max_missed_hbs, that member will be suspected. When a message or a heartbeat are received, the counter is reset to 0.
    Version:
    $Revision: 1.19.2.2 $
    Author:
    Bela Ban Aug 2002
    • Constructor Detail

      • FD_SIMPLE

        public FD_SIMPLE()
    • Method Detail

      • getName

        public java.lang.String getName()
        Specified by:
        getName in class Protocol
      • init

        public void init()
                  throws java.lang.Exception
        Description copied from class: Protocol
        Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
        Overrides:
        init in class Protocol
        Throws:
        java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception
      • setProperties

        public boolean setProperties​(java.util.Properties props)
        Description copied from class: Protocol
        Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:
         "loopback=false;unicast_inport=4444"
         
        Overrides:
        setProperties in class Protocol
      • stop

        public void stop()
        Description copied from class: Protocol
        This method is called on a Channel.disconnect(). Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed
        Overrides:
        stop in class Protocol
      • up

        public java.lang.Object up​(Event evt)
        Description copied from class: Protocol
        An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().
        Overrides:
        up in class Protocol
      • down

        public java.lang.Object down​(Event evt)
        Description copied from class: Protocol
        An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().
        Overrides:
        down in class Protocol