Motivations
Contributions
• Pervasive computing applications need robustness • Current approaches: • Middleware are too generic • There is a lack of programming support
• PerIDL: Declarative support for characterizing pervasive computing areas • PerGen: A PerIDL compiler to generate area-specific programming frameworks • Programming support for developing pervasive computing services • Consistency verifications from design to compile time, to run time • PerGen middleware: run time support for pervasive computing applications
The PerIDL Specification Defining a Pervasive Computing Area Service class name
A PerIDL specification for the Building Surveillance Area
- describe non functional variations of a class of services Semantic properties - defined by data types - used by the service discovery mechanism - describe how services interacts with each other - Specify the interaction mode (command | event | session) - Specify the control flow (input | output) - Specify the exchanged data types
Functionalities
• PerIDL specifications define • A taxonomy of service classes relevant to a given area
Domain Expert Device
DataCenter
Location location Command
interface Webcam : Device { attribute Video videoCapacities; SessionInput(Video video); }
interface MotionDetectingWebcam : ZoomingWebcam { EventOutput(Motion motion); }
Declarative support for consively characterizing a pervasive area
Service Command
interface ZoomingWebcam : Webcam { attribute boolean isOpticalZoom; void rotate(int angle); void tilt(int angle); void zoom(Region region); }
PerIDL: Domain-specific Interface Definition Language (IDL)
Webcam Video videoCapacities SessionInput
Manager Priority priority
Command
Actuator
Contact
Renderer
Command
Agenda
MotionDetection Manager
EventOutput
Command
EventInput SessionBinder
PTZWebcam bool hasOpticalZoom int zoomPower Command
Light
MotionDetecting Webcam
• PerIDL specifications are • Used by programmers as a high-level reference model • Checked for consistency at both area and application levels
Screen Video videoCapacities SessionInput
Command
• Functionalities and properties of each service class
• Passed to a compiler that generates programming frameworks PlasmaScreen
PDA Audio audioCapacities SessionInput
EventOutput
The PerGen Compiler Generating the Programming Framework
Example: framework for MotionDetectionManager
PerGen Compiler
interface
functionality
"interface" IManager
"interface" StartStop + start() + stop()
PerGen Compiler
"interface" IVideoSessionBinder + bridge(1: IMotionVideoSessionInput, s2: IMotionVideoSessionInput): int + disconnect(int) + disconnect(s: VideoSession)
• Checks PerIDL consistency • Generates an Area-Specific Programming Framework
"interface" IMotionDetection Manager
PerGen Compiler
PerGen Middleware
abstract service
• Adressing pervasive computing environments • Generic Service Broker • Customized w.r.t. the target application area • PerGen Programming Framework • Supporting 3 Interaction Modes
Event Notification
Service Broker
}
Generic
• Session (Parameter negotiation)
The PerGen Programming Framework Supporting Pervasive Computing Applications Development • Defining a service by extending its corresponding abstract class • Service registration by calling the parent constructor • Semantic property (e.g., priority) • Abstract methods (e.g., receive) • Provided methods (e.g., bridge)
public class HallMotionDetectionManager extends MotionDetectionManager { private MotionDetectingWebcam myWebcam; public HallMotionDetectionManager(String uri) { super(uri); priority.set(Priority.HIGH);
public class HallMotionDetectionManager extends MotionDetectionManager {
MotionDetectingWebcamFilter filter = MotionDetectingWebcam.getFilter(); filter.location.set(Location.HALL); filter.hasOpticalZoom.set(true); myWebcam = MotionDetectingWebcam.getService(filter);
public HallMotionDetectionManager(String uri) { super(uri); // TODO Auto-generated constructor stub } public void receive(Motion event, Service source) { // TODO Auto-generated method stub }
}
public void start() { // TODO Auto-generated method stub }
Class skeleton as generated by an IDE (e.g., Eclipse)
2. Refining the filter by specifying semantic properties
}
# bridge(s1: IMotionVideoSessionInput, s2: IMotionVideoSessionInput): int # disconnect(int) + getService(MotionDetectionManagerFilter): MotionDetectionManager + getServices(MotionDetectionManagerFilter) : LinkedList + getFilter(): MotionDetectionManagerFilter
+ receive(event: Event) + disconnect(s: VideoSession)
MotionDetectionManagerFilter
• Command: Abstract methods (e.g., zoom) • Event consumer • Abstract receive method for each event type • Event producer • Provided publish method for each event type • Subscriptions handled by the middleware • Session Invitee • Abstract connect and disconnect methods for each data type • Session Binder • Provided bridge and disconnect methods for each data type
• Service Registration Verifications (compile time) • Semantic property values (e.g., priority) • Service Discovery Verifications (compile time) • Service class filtering (e.g., PDA) • Semantic property values (e.g., location)
int idSession = bridge(myPDA, myWebcam); [...]
1. Selecting a filter to select a node in the PerIDL hierarchy
MotionDetectionManager
Verifications
PDAFilter filter = PDA.getFilter(); filter.owner.set(People.GUARD); PDA myPDA = PDA.getService(filter);
Service Discovery Support
MotionDetectionManager
myWebcam.subscribe(this);
public void receive(Motion event, Service source) { Region region = event.getRegion(); myWebcam.zoom(region);
public void stop() { // TODO Auto-generated method stub }
ManagerFilter + priority: Priority
Service Invocation Support
Application developers
Service Definition Support
Manager
• Abstract service classes support Service Definition • Concrete and abstract methods corresponding to functionalities • Instance variables corresponding to semantic properties • Filter classes support Service Discovery • Proxy classes support Remote Service Invocation
Middleware
• Event (Typed publish-subscribe)
ServiceFilter +uri: URI
+ start() + stop()
PerGen Programming Framework
• Command (RPC-like)
}
Manager + priority: Priority
Driver developers
Service Invocation
Service
Application developers
Applications
{
filter
proxy
Service + uri: URI
• Generic Service Invocation • Generic Event Notification
"interface" IMotionEventInput + receive(event: Motion)
• Service Invocation Verifications • Direction of interaction modes (compile time)
} [...]
• Connectivity of services (run time) • Typed service interaction (compile time)
3. Getting one or all services matching this filter
*
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Wilfried Jouve , Julien Lancia , Nicolas Palix*, Charles Consel*, Julia Lawall§ *
{jouve, palix, consel}@inria.fr INRIA, Phoenix Research Group
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[email protected] Thales / INRIA
§
[email protected] DIKU, Denmark
