Package org.jgroups.protocols

Class BARRIER

java.lang.Object
org.jgroups.stack.Protocol
org.jgroups.protocols.BARRIER
All Implemented Interfaces:
Lifecycle
public class BARRIER extends Protocol
All messages up the stack have to go through a barrier (read lock, RL). By default, the barrier is open. When a CLOSE_BARRIER event is received, we close the barrier by acquiring a write lock (WL). This succeeds when all previous messages have completed (by releasing their RLs). Thus, when we have acquired the WL, we know that there are no pending messages processed.

When an OPEN_BARRIER event is received, we simply open the barrier again and let all messages pass in the up direction. This is done by releasing the WL.

  • Field Details

    • max_close_time

      protected long max_close_time

    • flush_timeout

      protected long flush_timeout

    • lock

      protected final Lock lock

    • barrier_closed

      protected final AtomicBoolean barrier_closed

    • no_pending_threads

      protected Condition no_pending_threads
      signals to waiting threads that the barrier is open again

    • in_flight_threads

      protected Map<Thread,Object> in_flight_threads

    • barrier_opener_future

      protected volatile Future<?> barrier_opener_future

    • timer

      protected TimeScheduler timer

    • holes

      protected final Set<Address> holes

    • mcast_queue

      protected final Map<Address,Message> mcast_queue

    • ucast_queue

      protected final Map<Address,Message> ucast_queue

    • transport

      protected TP transport

    • NULL

      protected static final Object NULL

  • Constructor Details

    • BARRIER

      public BARRIER()

  • Method Details

    • getMaxCloseTime

      public long getMaxCloseTime()

    • setMaxCloseTime

      public BARRIER setMaxCloseTime(long m)

    • getFlushTimeout

      public long getFlushTimeout()

    • setFlushTimeout

      public BARRIER setFlushTimeout(long f)

    • isClosed

      public boolean isClosed()

    • getHoles

      public String getHoles()

    • getNumberOfInFlightThreads

      public int getNumberOfInFlightThreads()

    • getInFlightThreadsCount

      public int getInFlightThreadsCount()

    • isOpenerScheduled

      public boolean isOpenerScheduled()

    • init

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

    • stop

      public void stop()
      Description copied from class: Protocol
      Called on a JChannel.disconnect(); stops work (e.g. by closing multicast socket). Will be called from top to bottom.
      Specified by:
      stop in interface Lifecycle
      Overrides:
      stop in class Protocol

    • destroy

      public void destroy()
      Description copied from class: Protocol
      This method is called on a JChannel.close(). Does some cleanup; after the call, the VM will terminate
      Specified by:
      destroy in interface Lifecycle
      Overrides:
      destroy in class Protocol

    • down

      public Object down(Event evt)
      Description copied from class: Protocol
      An event is to be sent down the stack. A protocol 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 protocol may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down().
      Overrides:
      down in class Protocol

    • up

      public Object up(Event evt)
      Description copied from class: Protocol
      An event was received from the protocol below. Usually the current protocol 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

    • up

      public Object up(Message msg)
      Description copied from class: Protocol
      A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.
      Overrides:
      up in class Protocol

    • up

      public void up(MessageBatch batch)
      Description copied from class: Protocol
      Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

      The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

      Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.iterator(Predicate)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

      Overrides:
      up in class Protocol
      Parameters:
      batch - The message batch

    • unblock

      protected void unblock(Thread current_thread)

    • closeBarrier

      public void closeBarrier() throws TimeoutException
      Close the barrier. Temporarily remove all threads which are waiting or blocked, re-insert them after the call
      Throws:
      TimeoutException

    • openBarrier

      public void openBarrier()

    • printInFlightThreads

      protected String printInFlightThreads()

    • flushQueue

      protected void flushQueue(Map<Address,Message> queue)

    • scheduleBarrierOpener

      protected void scheduleBarrierOpener()

    • cancelBarrierOpener

      protected void cancelBarrierOpener()