Package org.jgroups.protocols

Class FORK

  • public class FORK
extends Protocol
    The FORK protocol; multiplexes messages to different forks in a stack (https://issues.jboss.org/browse/JGRP-1613). See doc/design/FORK.txt for details
    Since:
    3.4
    Author:
    Bela Ban

    • Field Detail

      • ID

        public static short ID

      • config

        protected java.lang.String config

      • process_state_events

        protected boolean process_state_events

      • fork_stacks

        protected final java.util.concurrent.ConcurrentMap<java.lang.String,​Protocol> fork_stacks

      • local_addr

        protected Address local_addr

    • Constructor Detail

      • FORK

        public FORK()

    • Method Detail

      • setUnknownForkHandler

        public void setUnknownForkHandler​(UnknownForkHandler unknownForkHandler)

      • get

        public Protocol get​(java.lang.String fork_stack_id)

      • putIfAbsent

        public Protocol putIfAbsent​(java.lang.String fork_stack_id,
                            Protocol prot)

      • remove

        public void remove​(java.lang.String fork_stack_id)

      • getForkStacks

        public int getForkStacks()

      • 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

      • 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

      • 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(org.jgroups.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.getMatchingMessages(short,boolean)), 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

      • getStateFromMainAndForkChannels

        protected void getStateFromMainAndForkChannels​(Event evt)

      • getStateFrom

        protected void getStateFrom​(JChannel channel,
                            Protocol prot,
                            java.lang.String stack,
                            java.lang.String ch,
                            java.io.DataOutputStream out)
                     throws java.lang.Exception
        Throws:
        java.lang.Exception

      • setStateInMainAndForkChannels

        protected void setStateInMainAndForkChannels​(java.io.InputStream in)

      • createForkStacks

        protected void createForkStacks​(java.lang.String config)
                         throws java.lang.Exception
        Throws:
        java.lang.Exception

      • createForkStacks

        protected void createForkStacks​(java.util.Map<java.lang.String,​java.util.List<ProtocolConfiguration>> protocols)
                         throws java.lang.Exception
        Throws:
        java.lang.Exception

      • parse

        public void parse​(XmlNode node)
           throws java.lang.Exception
        Description copied from class: Protocol
        Called by the XML parser when subelements are found in the configuration of a protocol. This allows a protocol to define protocol-specific information and to parse it
        Overrides:
        parse in class Protocol
        Throws:
        java.lang.Exception

      • createForkStack

        public ProtocolStack createForkStack​(java.lang.String fork_stack_id,
                                     java.util.List<Protocol> protocols,
                                     boolean initialize)
                              throws java.lang.Exception
        Returns the fork stack for fork_stack_id (if exitstent), or creates a new fork-stack from protocols and adds it into the hashmap of fork-stack (key is fork_stack_id). Method init() will be called on each protocol, from bottom to top.
        Parameters:
        fork_stack_id - The key under which the new fork-stack should be added to the fork-stacks hashmap
        protocols - A list of protocols from bottom to top to be inserted. They will be sandwiched between ForkProtocolStack (top) and ForkProtocol (bottom). The list can be empty (or null) in which case we won't create any protocols, but still have a separate fork-stack inserted.
        initialize - If false, the ref count 'inits' will not get incremented and init() won't be called. This is needed when creating a fork stack from an XML config inside of the FORK protocol. The protocols in the fork stack will only get initialized on the first ForkChannel creation
        Returns:
        The new ForkProtocolStack, or the existing stack (if present)
        Throws:
        java.lang.Exception

      • getForkStream

        public static java.io.InputStream getForkStream​(java.lang.String config)
                                         throws java.io.IOException
        Throws:
        java.io.IOException