jade.core
Class NodeFailureMonitor

java.lang.Object
  jade.core.NodeFailureMonitor

public abstract class NodeFailureMonitor
extends java.lang.Object

The abstract class NodeFailureMonitor provides a basic implementation for classes that are used to monitor the availability of nodes and detect node failures. In addition to that it provides static methods to initialize and create instances of monitors depending on the current settings in the profile. An instance of a subclass of the NodeFailureMonitor can only supervise a single node. If there are additional nodes in the same JVM, you can add these as child nodes. A child node is not supervised directly. Instead it has always the same state than its parent node. So if the parent node gets unreachable automatically all its child nodes will turn to the state unreachable.

Since JADE 3.3 there are two different types of failure monitoring available:

• Blocking failure monitoring based on RMI (Default)
• UDP based failure monitoring

The failure monitoring can be configured through the following profile parameter:

Parameter	Description	PC	MC
jade_core_NodeFailureMonitor_udp (*)	If true, indicates that the UDP based failure monitoring has to be used. If false or not specified the default RMI based failure monitoring is activated.	X	X
jade_core_NodeFailureMonitor_udp-port	Specifies the port number where the main container will listen for UDP pings. The default value is 28000. (This parameter is only used in combination with (*)	X	X
jade_core_NodeFailureMonitor_udp-ping-delay-limit	Defines the maximum time (in milliseconds) the main container will wait for incoming ping messages. The default value is 3000. (This parameter is only used in combination with (*)		X
jade_core_NodeFailureMonitor_udp-unreachable-limit	Defines the maximum time (in milliseconds) a node can be temporarily unreachable until it gets removed from the platform. The default value is 10.000. (This parameter is only used in combination with (*)		X
jade_core_NodeFailureMonitor_udp-ping-delay	Defines the time interval (in milliseconds) in which a peripheral container sends UDP ping messages to the main container. The default value is 1.000. (This parameter is only used in combination with (*)	X

MC ... main container PC ... peripheral container

Author:

Roland Mungenast - Profactor

See Also:

NodeEventListener

Field Summary

protected Map	childNodes
protected NodeEventListener	listener
protected Node	target

Constructor Summary

NodeFailureMonitor()

Method Summary

void	addChild(Node n) Add a child node for monitoring.
protected void	fireNodeAdded() Fire a NODE ADDED event
protected void	fireNodeReachable() Fire a NODE REACHABLE event
protected void	fireNodeRemoved() Fire a NODE REMOVED event
protected void	fireNodeUnreachable() Fire a NODE UNREACHABLE event
static NodeFailureMonitor	getFailureMonitor() Factory method to create NodeFailureMonitor objects
Node	getNode() Return the monitored target node
static void	init(jade.core.nodeMonitoring.NodeMonitoringService nms)
void	removeChild(Node n) Remove a child node from monitoring
void	start(Node n, NodeEventListener nel) Start the monitoring
abstract void	stop() Stop the monitoring

Methods inherited from class java.lang.Object

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

Field Detail

target

protected Node target

listener

protected NodeEventListener listener

childNodes

protected Map childNodes

Constructor Detail

NodeFailureMonitor

public NodeFailureMonitor()

Method Detail

start

public void start(Node n,
                  NodeEventListener nel)

Start the monitoring

Parameters:

n - target node to monitor

nel - listener to inform about new events

stop

public abstract void stop()

Stop the monitoring

addChild

public void addChild(Node n)

Add a child node for monitoring.

Parameters:

n - child node

removeChild

public void removeChild(Node n)

Remove a child node from monitoring

Parameters:

n - child node

getNode

public Node getNode()

Return the monitored target node

fireNodeAdded

protected void fireNodeAdded()

Fire a NODE ADDED event

fireNodeRemoved

protected void fireNodeRemoved()

Fire a NODE REMOVED event

fireNodeReachable

protected void fireNodeReachable()

Fire a NODE REACHABLE event

fireNodeUnreachable

protected void fireNodeUnreachable()

Fire a NODE UNREACHABLE event

getFailureMonitor

public static NodeFailureMonitor getFailureMonitor()

Factory method to create NodeFailureMonitor objects

Returns:

a new instance of a NodeFailureMonitor.

init

public static void init(jade.core.nodeMonitoring.NodeMonitoringService nms)