Package org.jgroups.protocols

Class BATCH

  • All Implemented Interfaces:
    Lifecycle
    public class BATCH
extends Protocol
    Batches messages near the top of the stack. This reduces the work done on the IO thread and reduces overhead, greatly increasing throughput for smaller message sizes (<1k in test configurations). Also reduces the amount of header data by having one header for each batch. Conceptually, down messages are buffered then put in a wrapper message, so lower protocols only interact with the wrapper. On the receiving end, the batch is unwrapped when it reaches this protocol and then forwarded to higher protocols as individual messages in a loop.
    Since:
    5.x
    Author:
    Chris Johnson

    • Field Detail

      • flush_interval

        protected long flush_interval

      • max_batch_size

        public int max_batch_size

      • num_msgs_sent

        protected long num_msgs_sent

      • num_ebs_sent

        protected long num_ebs_sent

      • num_ebs_sent_due_to_full_queue

        protected long num_ebs_sent_due_to_full_queue

      • num_ebs_sent_due_to_max_number_of_msgs

        protected long num_ebs_sent_due_to_max_number_of_msgs

      • num_ebs_sent_due_to_timeout

        protected long num_ebs_sent_due_to_timeout

      • running

        protected volatile boolean running

      • flush_task

        protected java.util.concurrent.Future<?> flush_task

    • Constructor Detail

      • BATCH

        public BATCH()

    • Method Detail

      • avgBatchSize

        public double avgBatchSize()

      • init

        public void init()
          throws java.lang.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:
        java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the the channel constructor will throw an exception

      • down

        public java.lang.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 java.lang.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

      • handleViewChange

        protected void handleViewChange​(java.util.List<Address> mbrs)

      • down

        public java.lang.Object down​(Message msg)
        Description copied from class: Protocol
        A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it, before passing it down.
        Overrides:
        down in class Protocol

      • up

        public java.lang.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

      • start

        public void start()
           throws java.lang.Exception
        Description copied from class: Protocol
        This method is called on a JChannel.connect(String); starts work. Protocols are connected ready to receive events. Will be called from bottom to top.
        Specified by:
        start in interface Lifecycle
        Overrides:
        start in class Protocol
        Throws:
        java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so JChannel.connect(String) will throw an exception

      • startFlushTask

        public void startFlushTask()

      • stopFlushTask

        public void stopFlushTask()

      • flush

        public void flush()