EPFD.oz

   1 functor
   2 import
   3    DistFramework(session:Session)
   4 export
   5    Epfd
   6 define
   7    fun{Epfd LM ?Uri}
   8       PP2P={LM getLayer('dist-layer:pp2p' $)}
   9       BEP2P={LM getLayer('dist-layer:bep2p' $)}
  10       Alarm={LM getLayer('dist-layer:alarm' $)}
  11       UUID='epfd(8525f024-6543-4108-abb8-2621617504a9)'
  12       SEND_DELAY=1000
  13       CHECK_DELAY=5000
  14    in
  15       Uri='dist-layer:epfd'
  16       class from Session
  17          attr
  18             sendAlarm
  19             checkAlarm
  20             pp2p
  21             bep2p
  22             h
  23             oldMonitored
  24             monitored
  25             monitoring
  26          meth init(SId Handler)
  27             h:=Handler
  28             sendAlarm:={Alarm init(UUID|sendAlarm|SId
  29                                    {self facet(alarm:Send $)})}
  30             checkAlarm:={Alarm init(UUID|checkAlarm|SId
  31                                     {self facet(alarm:Check $)})}
  32             pp2p:={PP2P init(UUID|pp2p|SId {self facet(pp2pDeliver:Deliver $)})}
  33             bep2p:={BEP2P init(UUID|bep2p|SId {self facet(bep2pDeliver:Deliver $)})}
  34             oldMonitored:={NewDictionary}
  35             monitored:={NewDictionary}
  36             monitoring:={NewDictionary}
  37             {@sendAlarm setAlarmIn(SEND_DELAY unit)}
  38             {@checkAlarm setAlarmIn(CHECK_DELAY unit)}
  39          end
  40          meth monitor(Remote)
  41             @monitored.(Remote.id):=false#Remote
  42             @oldMonitored.(Remote.id):=unit#Remote
  43             {@pp2p pp2pSend(Remote monitor())}
  44          end
  45          meth Deliver(From Msg)
  46             case Msg
  47             of monitor() then
  48                @monitoring.(From.id):=From
  49             [] imAlive() then
  50                @monitored.(From.id):=true#From
  51             end
  52          end
  53          meth Check(_)
  54             for X in {Dictionary.keys @monitored} do
  55                if @oldMonitored.X.1 \= @monitored.X.1 then
  56                   if @monitored.X.1 then
  57                      {@h alive(@monitored.X.2)}
  58                   else
  59                      {@h crash(@monitored.X.2)}
  60                   end
  61                   @oldMonitored.X:=@monitored.X
  62                end
  63                @monitored.X:=false#(@monitored.X.2)
  64             end
  65             {@checkAlarm setAlarmIn(CHECK_DELAY unit)}
  66          end
  67          meth Send(_)
  68             for X in {Dictionary.items @monitoring} do
  69                {@bep2p bep2pSend(X imAlive)}
  70             end
  71             {@sendAlarm setAlarmIn(SEND_DELAY unit)}
  72          end
  73       end
  74    end
  75 end