context.arch.enactor
Class EnactorSubscriptionManager

java.lang.Object
  context.arch.enactor.EnactorSubscriptionManager

All Implemented Interfaces:

Handler

public class EnactorSubscriptionManager

extends java.lang.Object

implements Handler

This class manages CTK subscriptions on behalf of enactors. It generates discovery queries out of enactor references, and notifies enactors of any new widgets that match those references. If multiple enactors utilize one subscription manager, it tries to minimize the number of actual CTK subscriptions used for all enactors.

Author:

alann

Field Summary

static int

DEFAULT_PORT

Constructor Summary

EnactorSubscriptionManager()

EnactorSubscriptionManager(int port)

Method Summary

boolean	addEnactor(Enactor r) Adds an enactor to the ESM.
protected void	addEnactorReference(EnactorReference rwr) This method registers an EnactorReference with the ESM.
DataObject	executeWidgetService(java.lang.String subscriptionId, java.lang.String serviceName, java.lang.String functionName, Attributes input)
protected void	fireAddEventsForAll(Enactor e, EnactorListener sml)
protected BaseObject	getBaseObject()
DataObject	handle(java.lang.String subscriptionId, DataObject data) This abstract method is used to generically handle any callbacks that a widget may support.
void	handleIndependentReply(IndependentCommunication independentCommunication) This method is used to forward the result of an independent communication
protected void	handleNewComponent(ComponentDescription cd) We see if any registered enactors (through references) are interested in this component.
protected void	init() subscribes to the CTK Discover with a query that retrieves information about all new widgets.
boolean	removeEnactor(Enactor r) Removes an enactor from the ESM, and removes all of its subscriptions.
protected void	removeEnactorReference(EnactorReference rwr) removed EnactorReference from manager.
protected java.util.Collection	sendDiscovererAttributeQuery(AbstractQueryItem q)
protected void	subscribe(ComponentDescription cd, EnactorReference rwr) Subscribes to the widget described by the component description, and binds it to the enactor reference.
protected void	unsubscribe(java.lang.String subscriptionId) Unsubscribes to the widget with the given subscription id, and notifies all bound enactor references.
protected void	updateWidgetSubscriptionCondition(java.lang.String subscriptionId) resubscribe to a currently subscribed widget with new conditions.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PORT

public static final int DEFAULT_PORT

See Also:

Constant Field Values

Constructor Detail

EnactorSubscriptionManager

public EnactorSubscriptionManager()

EnactorSubscriptionManager

public EnactorSubscriptionManager(int port)

Method Detail

addEnactor

public boolean addEnactor(Enactor r)
                   throws EnactorException

Adds an enactor to the ESM. If a new enactor, its references will be processed for subscriptions.

Parameters:

r - enactor to be added.

Returns:

true if rule was not already contained in the SM.

Throws:

EnactorException

removeEnactor

public boolean removeEnactor(Enactor r)
                      throws EnactorException

Removes an enactor from the ESM, and removes all of its subscriptions.

Parameters:

r - enactor to be removed.

Returns:

true if enactor in the SM.

Throws:

EnactorException

addEnactorReference

protected void addEnactorReference(EnactorReference rwr)
                            throws EnactorException

This method registers an EnactorReference with the ESM. The reference must be part of a registered Enactor. Enactors can call this method if they add new references to themselves at runtime.

Parameters:

rwr - the EnactorReference to add.

Throws:

SituationException - if the Enactor is not registered with the ESM.

EnactorException

removeEnactorReference

protected void removeEnactorReference(EnactorReference rwr)
                               throws EnactorException

removed EnactorReference from manager. This can be called at runtime by Enactors when they change their internal structure to notify the manager, but the Enactor must be part of the manager first by calling addRule.

Parameters:

rwr - the EnactorReference to be removed.

Throws:

EnactorException

fireAddEventsForAll

protected void fireAddEventsForAll(Enactor e,
                                   EnactorListener sml)

Parameters:

sml -

getBaseObject

protected BaseObject getBaseObject()

executeWidgetService

public DataObject executeWidgetService(java.lang.String subscriptionId,
                                       java.lang.String serviceName,
                                       java.lang.String functionName,
                                       Attributes input)

handleIndependentReply

public void handleIndependentReply(IndependentCommunication independentCommunication)

Description copied from interface: Handler

This method is used to forward the result of an independent communication

Specified by:

handleIndependentReply in interface Handler

handle

public DataObject handle(java.lang.String subscriptionId,
                         DataObject data)
                  throws InvalidMethodException,
                         MethodException

Description copied from interface: Handler

This abstract method is used to generically handle any callbacks that a widget may support. A context widget will call handle when a callback is triggered in the widget and the handler has subscribed to that callback.

Specified by:

handle in interface Handler

Parameters:

data - DataObject containing the data for the widget callback

Returns:

DataObject containing any directives to the widget that created the callback

Throws:

InvalidMethodException - if the specified callback can't be found

MethodException - is thrown if the specified callback can not be executed successfully

init

protected void init()

subscribes to the CTK Discover with a query that retrieves information about all new widgets.

handleNewComponent

protected void handleNewComponent(ComponentDescription cd)

We see if any registered enactors (through references) are interested in this component. If not we do nothing. If some enactor at a later date wants it, we'll get it again as a result of a query.

Parameters:

cd - description of component to be registered

subscribe

protected void subscribe(ComponentDescription cd,
                         EnactorReference rwr)

Subscribes to the widget described by the component description, and binds it to the enactor reference. We use the registry to bind the reference to an existing subscription if possible, before making a new CTK subscription.

unsubscribe

protected void unsubscribe(java.lang.String subscriptionId)

Unsubscribes to the widget with the given subscription id, and notifies all bound enactor references.

updateWidgetSubscriptionCondition

protected void updateWidgetSubscriptionCondition(java.lang.String subscriptionId)

resubscribe to a currently subscribed widget with new conditions.

sendDiscovererAttributeQuery

protected java.util.Collection sendDiscovererAttributeQuery(AbstractQueryItem q)