org.lsst.ccs.bus.jgroups

Class JGroupsBusMessagingLayer

java.lang.Object

org.lsst.ccs.bus.jgroups.JGroupsBusMessagingLayer

All Implemented Interfaces:

Closeable, AutoCloseable, BusMessagingLayer

public class JGroupsBusMessagingLayer
extends Object
implements BusMessagingLayer

Each Bus is represented by a JGroups cluster.

Each agent creates a JChannel, setName to name of agent and connect to corresponding Bus/cluster (so each agent may have up to 3 JChannel connected).
Each of these 3 channels have a JGroups Address.

for sending messages to an agent we have to find its Address in the group AND we have to find the addresses of the multiple anonymous agents that will receive a copy

There is a dictionary to match agent name to jGroups Address. for each agent there is an Address except for anonymous agent that can be matched to multiple addresses.

< p/> ImPortant every Jchannel in the JVM MUST be closed!

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_UDP_PROTOCOL

Fields inherited from interface org.lsst.ccs.bus.BusMessagingLayer

ANONYMOUS_AGENT

Constructor Summary

Constructors

Constructor and Description
JGroupsBusMessagingLayer() Deprecated.

Method Summary

Methods

Modifier and Type	Method and Description
void	addMessageListener(String agentName, BusMessageForwarder forwarder, Bus... buses)
void	close()
void	closeFor(String agentName, Bus... buses)
static org.jgroups.conf.XmlConfigurator	createXmlConfiguratorForBus(String xmlConfigurationFile, Properties properties, String bus) Creates an XmlConfiguration object for a given bus.
List<String>	getConnectedNames(Bus bus) gets a list of agent names connected to a bus.
void	register(String agentName, Bus... buses)
void	removeMessageListener(String agentName, BusMessageForwarder forwarder, Bus... buses)
<T extends BusPayload> void	sendMessage(String senderAgent, Bus<T> bus, T message, String... destinations)
void	setMembershipListener(BusMembershipListener listener, Bus... buses)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_UDP_PROTOCOL

public static final String DEFAULT_UDP_PROTOCOL

See Also:

Constant Field Values

Constructor Detail

JGroupsBusMessagingLayer

@Deprecated
public JGroupsBusMessagingLayer()

Deprecated.

there should be only one instance perJVM: it's up to the calling code to check that.

Method Detail

register

public void register(String agentName,
            Bus... buses)
              throws IOException

Specified by:

register in interface BusMessagingLayer

Throws:

IOException

createXmlConfiguratorForBus

public static org.jgroups.conf.XmlConfigurator createXmlConfiguratorForBus(String xmlConfigurationFile,
                                                           Properties properties,
                                                           String bus)

Creates an XmlConfiguration object for a given bus. This object is used to initialize a JChannel. The XmlConfiguration object is created from an xml file that is loaded from the bootstrap environment. The properties object is then scanned to find relevant values to modify XmlConfiguration object. The property keys are of the form org.lsst.ccs.jgroups.[BusIdentifier].[ProtocolName].[ProtocolPropertyName]=[ProtocolPropertyValue] Where: - BusIdentifier can be either COMMAND, LOG, STATUS if the property applied to an individual bus or ALL if it applies to all the buses. - ProtocolName is a valid JGroups protocol name as specified at http://www.jgroups.org/manual/html/protlist.html - ProtocolPropertyName is a property for the given protocol - ProtocolPropertyValue is the value to be given to it If the ProtocolName does not exist in the original xml file, a new ProtocolConfiguration object will be added to the XmlConfiguration.

Parameters:

xmlConfigurationFile - The name of the xml file to be loaded

properties - The properties object to be used to overwrite the xml file

bus - The bus for which the properties are scanned

Returns:

The XmlConfiguration object to be used to create the JChannel

closeFor

public void closeFor(String agentName,
            Bus... buses)

Specified by:

closeFor in interface BusMessagingLayer

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface BusMessagingLayer

Throws:

IOException

sendMessage

public <T extends BusPayload> void sendMessage(String senderAgent,
                                      Bus<T> bus,
                                      T message,
                                      String... destinations)
                 throws IOException

Specified by:

sendMessage in interface BusMessagingLayer

Throws:

IOException

addMessageListener

public void addMessageListener(String agentName,
                      BusMessageForwarder forwarder,
                      Bus... buses)

Specified by:

addMessageListener in interface BusMessagingLayer

removeMessageListener

public void removeMessageListener(String agentName,
                         BusMessageForwarder forwarder,
                         Bus... buses)

Specified by:

removeMessageListener in interface BusMessagingLayer

setMembershipListener

public void setMembershipListener(BusMembershipListener listener,
                         Bus... buses)

Specified by:

setMembershipListener in interface BusMessagingLayer

getConnectedNames

public List<String> getConnectedNames(Bus bus)

gets a list of agent names connected to a bus. There is no distinction between agents that are passive or not.

Specified by:

getConnectedNames in interface BusMessagingLayer

Parameters:

bus -

Returns:

a List of names (can be empty), anonymous agents are listed with a special Name