org.jgroups.protocols

Class UDP

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.TP

org.jgroups.protocols.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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	UDP.UcastReceiver

Nested classes/interfaces inherited from class org.jgroups.protocols.TP

TP.ProbeHandler, TP.ProtocolAdapter

Field Summary

Fields inherited from class org.jgroups.protocols.TP

bind_addr, channel_name, discard_incompatible_packets, global_thread_factory, local_addr, members, persistent_ports, persistent_ports_file, pm, pm_expiry_time, thread_naming_pattern, timer, timer_thread_factory, view

Fields inherited from class org.jgroups.stack.Protocol

down_prot, log, props, stack, stats, up_prot

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
protected java.net.DatagramSocket	createDatagramSocketWithBindPort() Creates a DatagramSocket when bind_port > 0.
protected java.net.DatagramSocket	createEphemeralDatagramSocket() Creates a DatagramSocket with a random port.
protected Address	createLocalAddress()
java.lang.String	getInfo()
java.lang.String	getName()
protected void	handleConfigEvent(java.util.Map<java.lang.String,java.lang.Object> map)
protected void	handleConnect()
protected void	handleDisconnect()
void	postUnmarshalling(Message msg, Address dest, Address src, boolean multicast)
void	postUnmarshallingList(Message msg, Address dest, boolean multicast)
void	run()
void	sendToAllMembers(byte[] data, int offset, int length) Send to all members in the group.
void	sendToSingleMember(Address dest, byte[] data, int offset, int length) Send to all members in the group.
void	setMcastPort(int p)
boolean	setProperties(java.util.Properties props) Setup the Protocol instance acording to the configuration string.
protected void	setThreadNames()
void	start() Creates the unicast and multicast sockets and starts the unicast and multicast receiver threads
void	stop() This method is called on a Channel.disconnect().
protected void	unsetThreadNames()

Methods inherited from class org.jgroups.protocols.TP

createThreadPool, destroy, down, dumpStats, getBindAddress, getBindPort, getBindToAllInterfaces, getChannelName, getDefaultThreadPool, getDefaultThreadPoolThreadFactory, getIncomingKeepAliveTime, getIncomingMaxPoolSize, getIncomingMaxQueueSize, getIncomingMessages, getIncomingMinPoolSize, getIncomingPoolSize, getIncomingQueueSize, getLocalAddress, getMaxBundleSize, getMaxBundleTimeout, getNumBytesReceived, getNumBytesSent, getNumMessagesReceived, getNumMessagesSent, getOOBKeepAliveTime, getOOBMaxPoolSize, getOOBMaxQueueSize, getOOBMessages, getOOBMinPoolSize, getOOBPoolSize, getOOBQueueSize, getOOBThreadPool, getOOBThreadPoolThreadFactory, getReceiveInterfaces, getSendInterfaces, getSingletonName, getThreadFactory, getThreadNamingPattern, getTimer, getTimerThreadFactory, getUpProtocols, handleDownEvent, init, isDefaulThreadPoolEnabled, isDiscardIncompatiblePackets, isEnable_unicast_bundling, isEnableBundling, isLoopback, isOOBThreadPoolEnabled, isReceiveOnAllInterfaces, isSendOnAllInterfaces, isUseIncomingPacketHandler, passToAllUpProtocols, receive, registerProbeHandler, resetStats, sendUpLocalAddressEvent, setBindAddress, setBindPort, setBindToAllInterfaces, setDefaultThreadPool, setDefaultThreadPoolThreadFactory, setDiscardIncompatiblePackets, setEnable_unicast_bundling, setEnableBundling, setIncomingKeepAliveTime, setIncomingMaxPoolSize, setIncomingMinPoolSize, setLoopback, setMaxBundleSize, setMaxBundleTimeout, setOOBKeepAliveTime, setOOBMaxPoolSize, setOOBMinPoolSize, setOOBThreadPool, setOOBThreadPoolThreadFactory, setThreadFactory, setTimerThreadFactory, toString, unregisterProbeHandler, up

Methods inherited from class org.jgroups.stack.Protocol

downThreadEnabled, enableStats, getDownProtocol, getProperties, getProtocolStack, getTransport, getUpProtocol, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, statsEnabled, upThreadEnabled

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

postUnmarshalling

public void postUnmarshalling(Message msg,
                     Address dest,
                     Address src,
                     boolean multicast)

Specified by:

postUnmarshalling in class TP

postUnmarshallingList

public void postUnmarshallingList(Message msg,
                         Address dest,
                         boolean multicast)

Specified by:

postUnmarshallingList in class TP

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