zeus.actors
Class MsgHandler

java.lang.Object
  java.lang.Thread
      zeus.actors.MsgHandler

All Implemented Interfaces:

java.lang.Runnable

public class MsgHandler

extends java.lang.Thread

The Message Handler component implements each Zeus agent's internal "mail sorting office", continually checking the incoming-message-queue of the MailBox for new messages, and forwarding them to the relevant components within the agent.

The Message Handler's behaviour is controlled by two factors: first, whether a new message represents the start of a new dialogue or it is part of an existing dialogue; and second, on the message processing rules registered with it by other components of the agent.

Change Log
----------

22/08/00 Altered spelling of organization to correct version for about 6 lines - Simon

Nested Class Summary

(package private) class	MsgHandler.AbilityLogger
protected class	MsgHandler.ReportLogger

Field Summary

protected MsgHandler.AbilityLogger	abilityLogger
protected java.util.Hashtable	abilityQueryTable
protected static int	ADD
protected java.util.Hashtable	addressQueryTable
(package private) java.util.Vector	attributeNodes
(package private) static int	cleanupInterval
protected AgentContext	context
protected static int	DELETE
protected HSet[]	eventMonitor
protected static int	FAIL
protected static int	FIRE
protected Queue	handleQ
protected RootNode	MessageRootNode
protected boolean	processing
protected MsgHandler.ReportLogger	reportLogger
protected java.util.Hashtable	reportQueryTable

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

MsgHandler()

MsgHandler(AgentContext context)

Method Summary

void	add_agents_abilities(Performative msg)
void	add_information(Performative msg)
void	add_task(Performative msg)
void	addMessageHandlerMonitor(MessageHandlerMonitor monitor, long event_type) If your code needs to react to changes in the MessageHandler use this to add a MessageHandlerMonitor.
void	address_of(Performative msg)
void	addRule(MessageRule r)
protected void	adviseAll(Address addr)
void	cancel_address(Performative msg)
void	cancel_message(Performative msg)
void	cancel_report(Performative msg)
void	cancel_specified_ability(Performative msg)
private void	debug(java.lang.String str)
void	delete_task(Performative msg)
protected java.util.Vector	dereference(java.util.Vector input) Replication to handle the problem of variable clashes when agents communicate with one another with variables in the content data;
void	deregister(Performative msg)
java.lang.Object	execRule(java.lang.String rule, java.lang.Object object, java.lang.String method, Performative input)
protected void	failure(Performative msg, java.lang.String content)
AgentContext	getAgentContext()
Queue	getMessageQueue()
void	has_ability(Performative msg)
protected void	inform(Performative msg, java.lang.String content)
void	isa_facilitator(Performative msg)
void	kill_yourself(Performative msg)
void	log_address(Performative msg)
void	log_message(Performative msg)
void	log_report(Performative msg)
void	log_specified_ability(Performative msg)
void	lowerStatus()
void	modify_task(Performative msg)
protected void	not_understood(Performative msg, java.lang.String content)
protected void	notifyMonitors(int type, MessageHandlerEvent event)
void	processMessage(Performative msg) in old versions of Zeus the msgHandler was responsible for ensuring that incomming messages were processed.
protected void	refuse(Performative msg, java.lang.String content)
void	register(Performative msg)
void	removeMessageHandlerMonitor(MessageHandlerMonitor monitor, long event_type)
void	removeRule(java.lang.String name)
void	run() thread main method - try and read incomming messages until the universe ends
private void	sendInstance(Task task, AgentContext context, java.lang.String target, java.lang.String replyWith)
private void	sendInstanceRange(Task task, AgentContext context, java.lang.String target, java.lang.String replyWith)
private void	sendProcess(Task task, AgentContext context, java.lang.String target, java.lang.String replyWith)
private void	sendProfile(Task task, AgentContext context, java.lang.String target, java.lang.String replyWith)
protected void	sendServiceDescriptions(java.lang.String target, java.lang.String replyWith)
void	stopProcessing()
private MailBox	waitForSetUp() refactored to help readability - this method loops until it gets a valid MailBox from the agent, so that the system can initialise in the right order
void	your_abilities(Performative msg)
void	your_relations(Performative msg)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

eventMonitor

protected HSet[] eventMonitor

ADD

protected static final int ADD

See Also:

Constant Field Values

FIRE

protected static final int FIRE

See Also:

Constant Field Values

DELETE

protected static final int DELETE

See Also:

Constant Field Values

FAIL

protected static final int FAIL

See Also:

Constant Field Values

addressQueryTable

protected java.util.Hashtable addressQueryTable

abilityQueryTable

protected java.util.Hashtable abilityQueryTable

reportQueryTable

protected java.util.Hashtable reportQueryTable

reportLogger

protected MsgHandler.ReportLogger reportLogger

abilityLogger

protected MsgHandler.AbilityLogger abilityLogger

processing

protected boolean processing

context

protected AgentContext context

MessageRootNode

protected RootNode MessageRootNode

attributeNodes

java.util.Vector attributeNodes

cleanupInterval

static int cleanupInterval

handleQ

protected Queue handleQ

Constructor Detail

MsgHandler

public MsgHandler()

MsgHandler

public MsgHandler(AgentContext context)

Method Detail

getAgentContext

public AgentContext getAgentContext()

lowerStatus

public void lowerStatus()

stopProcessing

public void stopProcessing()

waitForSetUp

private MailBox waitForSetUp()

refactored to help readability - this method loops until it gets a valid MailBox from the agent, so that the system can initialise in the right order

run

public void run()

thread main method - try and read incomming messages until the universe ends

processMessage

public void processMessage(Performative msg)

in old versions of Zeus the msgHandler was responsible for ensuring that incomming messages were processed. However this approach meant that reengineering of the msgHandler would be necessary whenever a mailbox was built that had more than one server - basically this was a problem in terms of both coupling the mailbox,server and msgHandler objects and reducing the coheasion of the msgHandler.

solution: processMessage is a method that can be called by any object to see if message rules have been set that apply to this message. The servers (inboxes) are responsible for calling this method which will process the message for them - or not as they like.

This method puts the message on a queue, which is internal to the msgHandler. The thread run by msgHandler will then process it. //synch

getMessageQueue

public Queue getMessageQueue()

addRule

public void addRule(MessageRule r)

removeRule

public void removeRule(java.lang.String name)

execRule

public java.lang.Object execRule(java.lang.String rule,
                                 java.lang.Object object,
                                 java.lang.String method,
                                 Performative input)

adviseAll

protected void adviseAll(Address addr)

register

public void register(Performative msg)

deregister

public void deregister(Performative msg)

kill_yourself

public void kill_yourself(Performative msg)

add_task

public void add_task(Performative msg)

modify_task

public void modify_task(Performative msg)

delete_task

public void delete_task(Performative msg)

cancel_message

public void cancel_message(Performative msg)

cancel_report

public void cancel_report(Performative msg)

cancel_specified_ability

public void cancel_specified_ability(Performative msg)

cancel_address

public void cancel_address(Performative msg)

log_message

public void log_message(Performative msg)

log_report

public void log_report(Performative msg)

log_address

public void log_address(Performative msg)

log_specified_ability

public void log_specified_ability(Performative msg)

address_of

public void address_of(Performative msg)

your_abilities

public void your_abilities(Performative msg)

sendServiceDescriptions

protected void sendServiceDescriptions(java.lang.String target,
                                       java.lang.String replyWith)

sendProfile

private void sendProfile(Task task,
                         AgentContext context,
                         java.lang.String target,
                         java.lang.String replyWith)

sendInstance

private void sendInstance(Task task,
                          AgentContext context,
                          java.lang.String target,
                          java.lang.String replyWith)

sendInstanceRange

private void sendInstanceRange(Task task,
                               AgentContext context,
                               java.lang.String target,
                               java.lang.String replyWith)

sendProcess

private void sendProcess(Task task,
                         AgentContext context,
                         java.lang.String target,
                         java.lang.String replyWith)

your_relations

public void your_relations(Performative msg)

has_ability

public void has_ability(Performative msg)

isa_facilitator

public void isa_facilitator(Performative msg)

add_agents_abilities

public void add_agents_abilities(Performative msg)

add_information

public void add_information(Performative msg)

refuse

protected void refuse(Performative msg,
                      java.lang.String content)

failure

protected void failure(Performative msg,
                       java.lang.String content)

not_understood

protected void not_understood(Performative msg,
                              java.lang.String content)

inform

protected void inform(Performative msg,
                      java.lang.String content)

addMessageHandlerMonitor

public void addMessageHandlerMonitor(MessageHandlerMonitor monitor,
                                     long event_type)

If your code needs to react to changes in the MessageHandler use this to add a MessageHandlerMonitor. This provides a programatic alternative to writing reaction rules

removeMessageHandlerMonitor

public void removeMessageHandlerMonitor(MessageHandlerMonitor monitor,
                                        long event_type)

notifyMonitors

protected void notifyMonitors(int type,
                              MessageHandlerEvent event)

dereference

protected final java.util.Vector dereference(java.util.Vector input)

Replication to handle the problem of variable clashes when agents communicate with one another with variables in the content data;

debug

private void debug(java.lang.String str)