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OSGi as an embedded Rich Internet Application Engine

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Introduction to

Rich Internet Applications(RIA)

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Rich Internet Applications

What are Rich Internet Apps (RIAs)?

Common base technologies:HTML, JavaScript, CSS, AJAX, Flash …

Frameworks:Adobe Air & Flex, Google WT, Gears, Yahoo Widgets…

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Rich Internet Applications

Why do we care?Job demand for „RIA“

Job demand for „Adobe Flex“

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Rich Internet Applications

RIAs on PCs: A Happy World…

… same thing for Mobile? …

Source: ethanmorrow.com

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Rich Internet Applications

Immature Technologies and Deployments No integration with phone functions (i.e. location)

Data bandwidth, Offline Mode Security, etc.

Source: abcnews.go.com

… NO!!!

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Introduction to

Rich Internet MobileNet Applications(RMA)

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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

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Rich MobileNet Applications

Traditional Approach to mobile Portals:

WebServer

Browser

WebServer

WebServer

Location PIM Bluetooth …

This persentation is NOT about this

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Rich MobileNet Applications

The new approach: RMA

WebServer

XYZServer

Browser

WebService

Location PIM Bluetooth …

Mobile OSGi

App

Service

My Local PortalWebServer

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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)

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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

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Phone OSPhone OS

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

Java

JS R JS R JS R JS R JS R

OSGi Browser

AP

I

AP

I

AP

I

AP

I

AP

I

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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

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Technology

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Remote Service Access - Architecture

UI Runtime (e.g. Browser)

OSGi

RSR

RSA

Service

Application(e.g widget)

ConvenienceLibrary

(e.g. JavaScript)

Se

rvic

e R

egis

try

ServiceObject

RemoteEvents

EventAdmin

3. find

4. bind

5. use

1. register

2. export

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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

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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

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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

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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)

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How to make a remote service

So, how to create a remote service?

By flagging it “remotable”:

org.osgi.remote.publish=true

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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

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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

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Session oriented service example - Messaging

public interface MessagingService { public String startSession(); public void stopSession(String sessionId);

/** * Result will be delivered to: * /com/prosyst/service/MessagingService/<sessionId> topic. */ public int sendSms(String sessionId, SMSMessage message, Map options);}

public class SMSMessage { public String[] recipients; public String body; public Map options;}

• Session ID• Request ID• Type: “MessageResult”

• Status: sent, pending, delivered or failed

• Recipients

• Session ID• Request ID• Type: “MessageError”

• Name• ErrorMessage

Success Event attributes Failure Event attributes

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Demo Application – Meet Me Here!

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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

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Service Lookup and Binding

<script src= "http://localhost/rsr/rsr_1.0.js">

</script><script type="text/javascript">

function bindService(service) { var sreg = RSR.find(service,null); if( sreg ) { return RSR.bind(sreg[0]); } else { alert("Can't find " + service + " service!"); }}const LOCATION= "com.prosyst.demo.rma.LocationService";

var locationService = bindService(LOCATION);

package com.prosyst.demo.rma;public interface LocationService { public Location getLocation();}

public class Activator implements BundleActivator {

public void start(BundleContext context) throws Exception {

Hashtable props = new Hashtable();

props.put( "org.osgi.remote.publish", Boolean.TRUE);

this.locationService = new LocationServiceImpl(context);

context.registerService( LocationService.class.getName(), this.locationService, props);

…

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Service Usage

var msg = "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;

}

var smsMessage = document.getElementById("smsMessage");smsMessage.value = msg;

package com.prosyst.demo.rma;public interface LocationService { public Location getLocation();}

public class Location {public double latitude;public double longitude;public double altitude;public long timestamp;

}

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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}}

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Demo

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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.

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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/

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Question?

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Contact

Member of:

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