org.universAAL.middleware.context

Class ContextSubscriber

java.lang.Object

org.universAAL.middleware.bus.member.BusMember

org.universAAL.middleware.bus.member.Subscriber

org.universAAL.middleware.context.ContextSubscriber

public abstract class ContextSubscriber
extends Subscriber

Provides the interface to be implemented by context subscribers together with shared code. Only instances of this class can subscribe for context events. The convention of the context bus regarding the registration parameters is the following:

• ContextPublishers provide only at the registration time info about themselves using ContextProvider.
• ContextSubscribers may pass an array of ContextEventPatterns as their initial subscriptions and can always add new (and remove old) subscriptions dynamically.

Author:

mtazari - Saied Tazari

Field Summary

Fields inherited from class org.universAAL.middleware.bus.member.BusMember

busResourceURI, owner, theBus

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ContextSubscriber(ModuleContext connectingModule, ContextEventPattern[] initialSubscriptions) Creates a Context Subscriber and immediately registers a set of Context Event Patterns for it, so it receives the matching events.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addNewRegParams(ContextEventPattern[] newSubscriptions) Registers more ContextEventPattern for this Subscriber in addition to those that might have passed initially
void	busDyingOut(AbstractBus b) This method is called when the bus is stopped to announce this to the bus members.
abstract void	communicationChannelBroken() Method to be called when the communication of the Subsccriber with the Context Bus is lost.
ContextEventPattern[]	getAllProvisions() Returns all provisions registered by all ContextPublishers on all instances of context bus in the current AAL Space.
String	getMyID()
abstract void	handleContextEvent(ContextEvent event) Method to be called when an Event forwarded in the Context Bus matches one of the Patterns registered by this Subscriber.
void	handleEvent(org.universAAL.middleware.bus.msg.BusMessage m)
protected void	removeMatchingRegParams(ContextEventPattern[] oldSubscriptions) Unregisters a set of ContextEventPattern that had been previously registered for this Subscriber.

Methods inherited from class org.universAAL.middleware.bus.member.BusMember

close, getComment, getLabel, getType, getURI, setComment, setLabel

Methods inherited from class java.lang.Object

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

Constructor Detail

ContextSubscriber

protected ContextSubscriber(ModuleContext connectingModule,
                 ContextEventPattern[] initialSubscriptions)

Creates a Context Subscriber and immediately registers a set of Context Event Patterns for it, so it receives the matching events.

Parameters:

connectingModule - The module context of the module creating the Publisher

initialSubscriptions - Array of ContextEventPattern that are immediately registered for this Subscriber

Throws:

NullPointerException - if newSubscriptions is null or one of the elements of that array is null

Method Detail

addNewRegParams

protected final void addNewRegParams(ContextEventPattern[] newSubscriptions)

Registers more ContextEventPattern for this Subscriber in addition to those that might have passed initially

Parameters:

newSubscriptions - The additional array of ContextEventPattern

Throws:

NullPointerException - if newSubscriptions is null or one of the elements of that array is null

removeMatchingRegParams

protected final void removeMatchingRegParams(ContextEventPattern[] oldSubscriptions)

Unregisters a set of ContextEventPattern that had been previously registered for this Subscriber. The Subscriber will no longer receive Events matching these Patterns.

Parameters:

oldSubscriptions -

communicationChannelBroken

public abstract void communicationChannelBroken()

Method to be called when the communication of the Subsccriber with the Context Bus is lost.

busDyingOut

public final void busDyingOut(AbstractBus b)

Description copied from class: BusMember

This method is called when the bus is stopped to announce this to the bus members.

Specified by:

busDyingOut in class BusMember

Parameters:

b - bus on which this member has been registered

See Also:

AbstractBus

getAllProvisions

public ContextEventPattern[] getAllProvisions()

Returns all provisions registered by all ContextPublishers on all instances of context bus in the current AAL Space.

handleContextEvent

public abstract void handleContextEvent(ContextEvent event)

Method to be called when an Event forwarded in the Context Bus matches one of the Patterns registered by this Subscriber.

Parameters:

event - The Context Event that matched the registered Patterns

Throws:

NullPointerException - if the event is null

handleEvent

public final void handleEvent(org.universAAL.middleware.bus.msg.BusMessage m)

getMyID

public String getMyID()