edu.vub.at.actors.natives
Class ELDiscoveryActor

java.lang.Object
  edu.vub.at.actors.eventloops.EventLoop
      edu.vub.at.actors.natives.ELActor
          edu.vub.at.actors.natives.ELDiscoveryActor

public final class ELDiscoveryActor

extends ELActor

Every VM has an associated Discovery Actor. This is a regular actor (with a native Actor Mirror) which is responsible for matching local publications with local and remote subscriptions.

Author:

tvcutsem

Nested Class Summary

Nested classes inherited from class edu.vub.at.actors.eventloops.EventLoop

EventLoop.EventProcessor

Field Summary

private DiscoveryManager

discoveryManager_ manages subscriptions and publications

Fields inherited from class edu.vub.at.actors.natives.ELActor

host_, receptionists_

Fields inherited from class edu.vub.at.actors.eventloops.EventLoop

eventQueue_, processor_

Constructor Summary

ELDiscoveryActor(ELVirtualMachine host)

Method Summary

void	event_batchRemotePublications(MultiMap matchingPublications) Received in response to the CMDJoinServices command of a remote VM
void	event_cancelPublication(DiscoveryManager.Publication pub) This event is fired whenever a service offer is being revoked.
void	event_cancelSubscription(DiscoveryManager.Subscription sub) This event is fired whenever a service request is being revoked.
void	event_clientSubscribed(DiscoveryManager.Subscription sub) This event is fired whenever an object requests a service using the require: language construct.
void	event_receiveNewSubscriptionsFrom(java.util.Set subscriptionTopics, org.jgroups.Address fromMember) When a VM is discovered by another VM, that VM can send its outstanding subscriptions to this VM.
void	event_remotePublication(Packet serializedProvidedTopic, Packet serializedProvidedService) Received in response to the CMDProvideService command of a remote VM
void	event_remoteSubscription(Packet serializedRequiredTopic, org.jgroups.Address replyTo) Received in response to the CMDRequireService command of a remote VM TODO: perhaps transform this into a sync_event and let CMDRequireService perform the reply
void	event_sendAllSubscriptionsTo(org.jgroups.Address newMember) When a new VM has been discovered, the discovery agent is responsible for sending all outstanding subscription topics to that VM, such that it can be checked whether the newcomer has some publications that can resolve outstanding requests.
void	event_servicePublished(DiscoveryManager.Publication pub) This event is fired whenever an object is being offered as a service provide using the provide: language construct.

Methods inherited from class edu.vub.at.actors.natives.ELActor

currentActor, event_accept, event_acceptSelfSend, event_init, event_serviceJoined, export, getActorMirror, getHost, handle, initRootObject, initSharedFields, resolve, setActorMirror, sync_event_eval, sync_event_performTest, sync_event_symbioticInvocation

Methods inherited from class edu.vub.at.actors.eventloops.EventLoop

currentEventLoop, execute, owner, receive, receiveAndWait, receivePrioritized, stopProcessing, toEventLoop, toString

Methods inherited from class java.lang.Object

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

Field Detail

discoveryManager_

private final DiscoveryManager discoveryManager_

manages subscriptions and publications

Constructor Detail

ELDiscoveryActor

public ELDiscoveryActor(ELVirtualMachine host)

Method Detail

event_servicePublished

public void event_servicePublished(DiscoveryManager.Publication pub)

This event is fired whenever an object is being offered as a service provide using the provide: language construct. The discovery actor keeps track of such services and is responsible for the matching between services and clients. When such matches are detected the VM will send a foundResolution event to both involved actors. If the VM detects that one partner has become unavailable it will send the lostResolution event

Parameters:

pub - - a publication containing the serialized forms of the topic and the exported service object

event_clientSubscribed

public void event_clientSubscribed(DiscoveryManager.Subscription sub)

This event is fired whenever an object requests a service using the require: language construct. The discovery manager keeps track of such requests and is responsible matching services and clients. When such matches are detected the VM will send a foundResolution event to both involved actors. If the VM detects that one partner has become unavailable it will send the lostResolution event

Parameters:

sub - - a subscription containing the serialized forms of the topic and the subscription handler

event_cancelPublication

public void event_cancelPublication(DiscoveryManager.Publication pub)

This event is fired whenever a service offer is being revoked. In this case, the discovery manager ensures that the object is no longer discoverable to new clients. However, it will not send disconnected events as these signal that an object has become unreachable. In other words: remote objects that had already discovered the object linked to this publication will maintain their connection.

Parameters:

pub - - the original publication object to cancel

event_cancelSubscription

public void event_cancelSubscription(DiscoveryManager.Subscription sub)

This event is fired whenever a service request is being revoked. In this case, the discovery manager ensures that the object will no longer discover new services. However, it will not send lostResolution events as these signal that the client has become unreachable.

Parameters:

sub - - the original subscription object to cancel

event_remotePublication

public void event_remotePublication(Packet serializedProvidedTopic,
                                    Packet serializedProvidedService)

Received in response to the CMDProvideService command of a remote VM

event_batchRemotePublications

public void event_batchRemotePublications(MultiMap matchingPublications)

Received in response to the CMDJoinServices command of a remote VM

Parameters:

matchingPublications - - a map from serialized ATStripe topics to Sets of serialized ATObjects that provide the serialized topic.

event_remoteSubscription

public void event_remoteSubscription(Packet serializedRequiredTopic,
                                     org.jgroups.Address replyTo)

Received in response to the CMDRequireService command of a remote VM TODO: perhaps transform this into a sync_event and let CMDRequireService perform the reply

event_sendAllSubscriptionsTo

public void event_sendAllSubscriptionsTo(org.jgroups.Address newMember)

When a new VM has been discovered, the discovery agent is responsible for sending all outstanding subscription topics to that VM, such that it can be checked whether the newcomer has some publications that can resolve outstanding requests.

event_receiveNewSubscriptionsFrom

public void event_receiveNewSubscriptionsFrom(java.util.Set subscriptionTopics,
                                              org.jgroups.Address fromMember)

When a VM is discovered by another VM, that VM can send its outstanding subscriptions to this VM. This event is received by an incoming CMDInitRequireServices command. The local discovery manager should, for each incoming subscription topic, assemble all matching local publication objects. A map of topic -> Set of publication objects is then returned to the sender VM.

Parameters:

subscriptionTopics - - a Set of Packet objects representing serialized ATStripe topics