org.jgroups.protocols.rules

Class SUPERVISOR

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.rules.SUPERVISOR

public class SUPERVISOR
extends Protocol

Protocol which supervises other protocols. Essentially a rule engine, where rule conditions are checked periodically, triggering (optional) actions. Example: start failure detection in FD is it isn't running

https://issues.jboss.org/browse/JGRP-1557

Since:

3.3

Author:

Bela Ban

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.lang.String	CLASS
protected java.lang.String	config
protected java.util.List<EventHandler>	event_handlers
protected BoundedList<java.lang.String>	executions
protected static java.lang.String	INTERVAL
protected Address	local_addr
protected static java.lang.String	NAME
protected int	num_event_handlers
protected static java.lang.String	RULE
protected java.util.Map<java.lang.String,Tuple<Rule,java.util.concurrent.Future<?>>>	rules
protected static java.lang.String	RULES
protected TimeScheduler	timer
protected View	view

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
SUPERVISOR()

Method Summary

Modifier and Type	Method and Description
void	addCondition(java.lang.String cond)
void	destroy() This method is called on a Channel.close().
java.lang.Object	down(Event evt) An event is to be sent down the stack.
java.lang.String	dumpRules()
java.lang.String	executions()
Address	getLocalAddress()
int	getNumRules()
View	getView()
protected void	handleView(View view)
void	init() Called after instance has been created (null constructor) and before protocol is started.
void	installRule(long interval, Rule rule) Installs a new rule
void	installRule(long interval, java.lang.String classname)
void	installRule(java.lang.String name, long interval, Rule rule) Installs a new rule
void	installRule(java.lang.String name, long interval, java.lang.String classname)
protected static void	match(java.lang.String expected_name, java.lang.String name, boolean is_element)
protected void	parseConfig(java.lang.String filename)
protected void	parseRule(org.w3c.dom.Node root)
protected void	parseRules(java.io.InputStream input)
void	register(EventHandler handler)
void	uninstallRule(java.lang.String name)
void	unregister(EventHandler handler)
java.lang.Object	up(Event evt) An event was received from the layer below.
void	up(MessageBatch batch) Sends up a multiple messages in a MessageBatch.

Methods inherited from class org.jgroups.stack.Protocol

accept, afterCreationHook, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, resetStats, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, start, statsEnabled, stop

Methods inherited from class java.lang.Object

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

Field Detail

local_addr

protected Address local_addr

view

protected volatile View view

timer

protected TimeScheduler timer

executions

protected final BoundedList<java.lang.String> executions

config

protected java.lang.String config

rules

protected final java.util.Map<java.lang.String,Tuple<Rule,java.util.concurrent.Future<?>>> rules

event_handlers

protected final java.util.List<EventHandler> event_handlers

num_event_handlers

protected volatile int num_event_handlers

RULES

protected static final java.lang.String RULES

See Also:

Constant Field Values

RULE

protected static final java.lang.String RULE

See Also:

Constant Field Values

NAME

protected static final java.lang.String NAME

See Also:

Constant Field Values

CLASS

protected static final java.lang.String CLASS

See Also:

Constant Field Values

INTERVAL

protected static final java.lang.String INTERVAL

See Also:

Constant Field Values

Constructor Detail

SUPERVISOR

public SUPERVISOR()

Method Detail

getLocalAddress

public Address getLocalAddress()

getView

public View getView()

executions

public java.lang.String executions()

addCondition

public void addCondition(java.lang.String cond)

getNumRules

public int getNumRules()

dumpRules

public java.lang.String dumpRules()

register

public void register(EventHandler handler)

unregister

public void unregister(EventHandler handler)

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

destroy

public void destroy()

Description copied from class: Protocol

This method is called on a Channel.close(). Does some cleanup; after the call the VM will terminate

Overrides:

destroy in class Protocol

installRule

public void installRule(long interval,
                        Rule rule)

Installs a new rule

Parameters:

interval - Number of ms between executions of the rule

rule - The rule

installRule

public void installRule(java.lang.String name,
                        long interval,
                        Rule rule)

Installs a new rule

Parameters:

name - The name of the rule

interval - Number of ms between executions of the rule

rule - The rule

installRule

public void installRule(java.lang.String name,
                        long interval,
                        java.lang.String classname)
                 throws java.lang.Exception

Throws:

java.lang.Exception

installRule

public void installRule(long interval,
                        java.lang.String classname)
                 throws java.lang.Exception

Throws:

java.lang.Exception

uninstallRule

public void uninstallRule(java.lang.String name)

down

public java.lang.Object down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. The layer 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 layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().

Overrides:

down in class Protocol

up

public java.lang.Object up(Event evt)

Description copied from class: Protocol

An event was received from the layer below. Usually the current layer 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 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

handleView

protected void handleView(View view)

parseConfig

protected void parseConfig(java.lang.String filename)
                    throws java.lang.Exception

Throws:

java.lang.Exception

parseRules

protected void parseRules(java.io.InputStream input)
                   throws java.lang.Exception

Throws:

java.lang.Exception

parseRule

protected void parseRule(org.w3c.dom.Node root)
                  throws java.lang.Exception

Throws:

java.lang.Exception

match

protected static void match(java.lang.String expected_name,
                            java.lang.String name,
                            boolean is_element)
                     throws java.lang.Exception

Throws:

java.lang.Exception