Package org.jgroups.protocols

Class UDP

  • All Implemented Interfaces:
    java.lang.Runnable
    public class UDP
extends TP
implements java.lang.Runnable
    IP multicast transport based on UDP. Messages to the group (msg.dest == null) will be multicast (to all group members), whereas point-to-point messages (msg.dest != null) will be unicast to a single member. Uses a multicast and a unicast socket.

    The following properties are read by the UDP protocol:

    • param mcast_addr - the multicast address to use; default is 228.8.8.8.
    • param mcast_port - (int) the port that the multicast is sent on; default is 7600
    • param ip_mcast - (boolean) flag whether to use IP multicast; default is true.
    • param ip_ttl - the default time-to-live for multicast packets sent out on this socket; default is 32.
    • param use_packet_handler - boolean, defaults to false. If set, the mcast and ucast receiver threads just put the datagram's payload (a byte buffer) into a queue, from where a separate thread will dequeue and handle them (unmarshal and pass up). This frees the receiver threads from having to do message unmarshalling; this time can now be spent receiving packets. If you have lots of retransmissions because of network input buffer overflow, consider setting this property to true.
    Version:
    $Id: UDP.java,v 1.156.2.16 2009/01/05 08:33:20 belaban Exp $
    Author:
    Bela Ban

    • Constructor Detail

      • UDP

        public UDP()
        Creates the UDP protocol, and initializes the state variables, does however not start any sockets or threads.

    • Method Detail

      • setProperties

        public boolean setProperties​(java.util.Properties props)
        Setup the Protocol instance acording to the configuration string. The following properties are read by the UDP protocol:
        • param mcast_addr - the multicast address to use default is 228.8.8.8
        • param mcast_port - (int) the port that the multicast is sent on default is 7600
        • param ip_mcast - (boolean) flag whether to use IP multicast - default is true
        • param ip_ttl - Set the default time-to-live for multicast packets sent out on this socket. default is 32
        Overrides:
        setProperties in class TP
        Returns:
        true if no other properties are left. false if the properties still have data in them, ie , properties are left over and not handled by the protocol stack

      • setMcastPort

        public void setMcastPort​(int p)

      • run

        public void run()
        Specified by:
        run in interface java.lang.Runnable

      • getInfo

        public java.lang.String getInfo()
        Specified by:
        getInfo in class TP

      • sendToAllMembers

        public void sendToAllMembers​(byte[] data,
                             int offset,
                             int length)
                      throws java.lang.Exception
        Description copied from class: TP
        Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member
        Specified by:
        sendToAllMembers in class TP
        Parameters:
        data - The data to be sent. This is not a copy, so don't modify it
        Throws:
        java.lang.Exception

      • sendToSingleMember

        public void sendToSingleMember​(Address dest,
                               byte[] data,
                               int offset,
                               int length)
                        throws java.lang.Exception
        Description copied from class: TP
        Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member
        Specified by:
        sendToSingleMember in class TP
        Parameters:
        dest - Must be a non-null unicast address
        data - The data to be sent. This is not a copy, so don't modify it
        Throws:
        java.lang.Exception

      • getName

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

      • start

        public void start()
           throws java.lang.Exception
        Creates the unicast and multicast sockets and starts the unicast and multicast receiver threads
        Overrides:
        start in class TP
        Throws:
        java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception

      • 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 TP

      • handleConnect

        protected void handleConnect()
                      throws java.lang.Exception
        Overrides:
        handleConnect in class TP
        Throws:
        java.lang.Exception

      • handleDisconnect

        protected void handleDisconnect()
        Overrides:
        handleDisconnect in class TP

      • createLocalAddress

        protected Address createLocalAddress()

      • createEphemeralDatagramSocket

        protected java.net.DatagramSocket createEphemeralDatagramSocket()
                                                         throws java.net.SocketException
        Creates a DatagramSocket with a random port. Because in certain operating systems, ports are reused, we keep a list of the n last used ports, and avoid port reuse
        Throws:
        java.net.SocketException

      • createDatagramSocketWithBindPort

        protected java.net.DatagramSocket createDatagramSocketWithBindPort()
                                                            throws java.lang.Exception
        Creates a DatagramSocket when bind_port > 0. Attempts to allocate the socket with port == bind_port, and increments until it finds a valid port, or until port_range has been exceeded
        Returns:
        DatagramSocket The newly created socket
        Throws:
        java.lang.Exception

      • setThreadNames

        protected void setThreadNames()
        Overrides:
        setThreadNames in class TP

      • unsetThreadNames

        protected void unsetThreadNames()
        Overrides:
        unsetThreadNames in class TP

      • handleConfigEvent

        protected void handleConfigEvent​(java.util.Map<java.lang.String,​java.lang.Object> map)
        Overrides:
        handleConfigEvent in class TP