OSGi As An Embedded Rich Internet Application Engine

OSGi as an embedded Rich Internet Application Engine

Introduction to
Rich Internet Applications
(RIA)

What are Rich Internet Apps (RIAs)?
Common base technologies:HTML, JavaScript, CSS, AJAX, Flash …
Frameworks:Adobe Air & Flex, Google WT, Gears, Yahoo Widgets…

Why do we care?
Job demand for „RIA“
Job demand for „Adobe Flex“

RIAs on PCs: A Happy World…
Source: ethanmorrow.com
… same thing for Mobile? …

Immature Technologies and Deployments
No integration with phone functions (i.e. location)
Data bandwidth, Offline Mode
Security, etc.
… NO!!!
Source: abcnews.go.com

Introduction to
Rich Internet MobileNet Applications
(RMA)

Rich MobileNet Applications
Rich Internet Application: ”Fully featured software package that runs in a browser.”- from Loosely Coupled (http://www.loselycoupled.com/glossary/RIA)
Movements to achieve “fully featured”:
Google Gears
OMTP BONDI
W3C Geolocation API
Incomplete/Work in progress
Specification work in BONDI ongoing
Implementations are browser and platform specific

Traditional Approach to mobile Portals:
Web
Server
Web
Server
Web
Server
Location
PIM
Bluetooth
…
Browser
This persentation
is NOT about this

The new approach: RMA
XYZ
Server
Web
Service
App
Service
Web
Server
Web
Server
Location
PIM
Bluetooth
…
Browser
Mobile OSGi
My Local Portal

Server in the pocket concept
The role of mobile phones changes
Content is created on the go
Photos taken by camera phones
Blog entries written on smart phones
Data collected via sensors
Location information
Services are provided at the edge of the network
For example phone as a content (media) server
Ad hoc connectivity
Local networks, peer to peer etc.
Different realizations of the concept – or parts:
Mobile web server: Nokia MyMobilesite.Net
Personal web server: Opera Unite (http://unite.opera.com)

OSGi – The Server In Your Pocket
HTTP Service: your personal web server
UPnP: for ad hoc connectivity and automatic configuration
Portability: runs on many different platforms (S60, WM, BREW, Android etc.)
Platform integration: existing Java APIs to access device functionality
Local web applications (widgets)
Remote Service Access: automatic export of services

OSGi enabling BONDI
BONDI is an emerging standard for browser JavaScript extensions (mostly for access to phone features)
OSGi is a component and service runtime
OSGi can inject BONDI into browsers
OSGi
Browser
Java
JSR
JSR
JSR
JSR
JSR
API
API
API
API
API
Phone OS
Phone OS

Services in your pocket
Horizontal services
Device integration or operator services
Shared by applications
Can be deployed post shipment
Application specific services:
Complex business logic implemented in Java
Can use the full power of Java
JEE-like 3-tier architecture in the device
Can leverage existing 3rd-party components

Technology

Remote Service Access - Architecture
UI Runtime
(e.g. Browser)
OSGi
Remote
Events
Event
Admin
Application
(e.g widget)
RSR
Convenience
Library
(e.g. JavaScript)
Service Registry
3. find
2. export
RSA
4. bind
Service
Service
Object
5. use
1. register

Widgets
Locally installed web applications
Support for W3C Widget specification
Widget use HTML and CSS as the markup
Metadata provided in config.xml
Packaged as a ZIP
Widgets are fully manageable via OSGi
Secure widget execution: security context spans from OSGi to the Browser

Remote Service Access
Based on Distributed OSGi concept
Bindings specified for JSON RPC – lightweight and fits JavaScript naturally
Services can be marked for export
Access point and skeleton automatically created
IDL: Java – simple mapping to JavaScript (with some restrictions)
Remote Service Registry (RSR)
Available at a well-know URL
Accessible via a well-known (JSON) web service interface

Service Model
Asymmetric: service provider OSGi, service consumer UI Runtime
Synchronous method calls
Parameters passed by value
No callbacks, no listeners…
Event support: to prevent polling in the applications
Applications can subscribe to Event Admin topics

Convenience Library
Remote Service Access is specified in terms of protocols and access points
Ensures interoperability with any UI Runtime
A JavaScript convenience library is provided for better developer experience
Simple API to access RSR – find and bind services
Automatically generates stubs for using bound services
Subscribe to remote events (listeners)

How to make a remote service
So, how to create a remote service?
By flagging it “remotable”:
org.osgi.remote.publish=true

Best design practices for remote services
Use simple types as parameters
Primitive types and their wrappers
Strings
JavaBeans
Classes with default constructor and public members
Maps
Arrays (homogeneous)
Synchronous methods should return quickly
If operation takes longer, use notifications
Session-oriented services

Session oriented services
startSession: returns session ID
Session ID used to identify an Event Admin topic.
Notifications are delivered through that topic
Session ID is used in each service request to identify the session
asynchServiceMethod: returns request ID
Events related to this request carry the request ID

Session oriented service example - Messaging
public interface MessagingService {
public String startSession();
publicvoidstopSession(String sessionId);
/**
* Result will be delivered to:
* /com/prosyst/service/MessagingService/<sessionId> topic.
*/
publicintsendSms(String sessionId, SMSMessage message, Map options);
}
public class SMSMessage {
public String[] recipients;
public String body;
public Map options;
}
Success Event attributes
Failure Event attributes
Session ID
Request ID
Type: “MessageResult”
Session ID
Request ID
Type: “MessageError”
Status: sent, pending, delivered or failed
Recipients
Name
ErrorMessage

Demo Application – Meet Me Here!

Demo – Meet Me Here!
Meet Me Here! is a simple web application
Select a contact from the device contact list and send him a message
The default message contains a Google Map URL with the current location of the user
Implemented as a widget and a service bundle to access device features
Three remote services: contacts, location, messaging
Installed from a single deployment package

Service Lookup and Binding
<script src="http://localhost/rsr/rsr_1.0.js">
</script>
<script type="text/javascript">
functionbindService(service) {
varsreg = RSR.find(service,null);
if( sreg ) {
returnRSR.bind(sreg[0]);
} else {
alert("Can't find " + service
+ " service!");
}
}
const LOCATION=
"com.prosyst.demo.rma.LocationService";
varlocationService =
bindService(LOCATION);
packagecom.prosyst.demo.rma;
publicinterfaceLocationService {
public Location getLocation();
}
public class Activator implementsBundleActivator {
public void start(BundleContext context) throws Exception {
Hashtable props = newHashtable();
props.put( "org.osgi.remote.publish", Boolean.TRUE);
this.locationService = newLocationServiceImpl(context);
context.registerService( LocationService.class.getName(), this.locationService, props);
…

Service Usage
varmsg = "Location service not available";
if( !locationService ) {
locationService =
bindService(LOCATION_SERVICE);
}
var location = false;
if( locationService ) {
location = locationService.getLocation();
}
if( location ) {
msg = "Meet Me Here: " + "http://maps.google.com/maps?q=" + location.latitude + ", " + location.longitude;
}
varsmsMessage =
document.getElementById("smsMessage");
smsMessage.value = msg;
packagecom.prosyst.demo.rma;
publicinterfaceLocationService {
public Location getLocation();
}
public class Location {
public double latitude;
public double longitude;
public double altitude;
public long timestamp;
}

JSON RPC – Lightweight web service protocol
Specification: http://json-rpc.org/wd/JSON-RPC-1-1-WD-20060807.html
Request:
{"version":"1.1","method":"getLocation","params":[]}
Response:
{"version":"1.1","result":{"altitude":0,"timestamp":1242744765930,"latitude":47.434006,"longitude":19.148868}}

Summary
“Mobile Web Applications will beat native applications”Daniel K. Appelquist (http://www.torgo.com/blog/2008/10/mobile-web-native-apps.html)
Using OSGi – you can take the best of both worlds:
Web developers & designers build the front-end
Java developers build the app logic
… and OSGi ensures the transparent interworking.
Having a server on the edge of the network changes the way things work.

Where To Start?
Devices: First MASS Deployment in US in 2009. – Project Name: Sprint Titan
Shipping 5 device models during 2009
On 3 different platforms: Windows Mobile, BREW, 3rd platform
OSGi for Android Download: http://dz.prosyst.com/oss#mBS_Android
2009 Sprint Open Developer Conference http://developer.sprint.com/devcon2009
My blog: http://picisblog.blogspot.com/

Question?

Contact
Gábor Pécsy
g.pecsy@prosyst.com
Mobile: +36 70 385 5821
http://picisblog.blogspot.com
ProSyst Software GmbH
Dürener Straße 405
D-50858 Cologne, Germany
Tel. +49 221 6604-0
Fax +49 221 6604-660
info@prosyst.com
www.prosyst.com
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OSGi As An Embedded Rich Internet Application Engine

by pecsy on Jun 26, 2009

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