J2ME and the

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J2ME and the
IVY Platform


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Agenda

Digital Focus

J2ME

•
Quick overview

•
What’s in & what’s out

•
Networking capabilities

IVY & JXTA

•
Why and what

•
IVY Architecture and Design

•
JXTA protocols and components




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Digital Focus

Founded in 1995

Headquartered in Herndon, Virginia

Long history of excellence with Java technology…



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Our Clients


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J2ME

J2ME
–

Java 2 MicroEdition

•
Java for small, mobile and embedded devices

•
Configurations (horizontal)

•
CLDC, CDC

•
Profiles (vertical)

•
MIDP, Foundation, Palm


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J2ME Architecture

CLDC Configuration

•
KVM, networking

•
Lowest common
denominator for
portability

•
No optional elements

MID profile

•
GUI

•
RMS

•
Timers

•
Lifecycle



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What’s missing

Reduced number support

•
float, double primitives

•
Double, Float classes

Extendable UI components

•
Final High
-
level components

•
New components subclass Canvas

Lacks:

•
JNI

•
Sound API

•
Serialization

•
Reflection

•
User defined class loaders



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Networking

Only HTTP is required with CLDC

•
Not great for mobile wireless solutions

•
Stateful
–

tough with mobile IP

•
Stream oriented

Generic Connection Framework

•
Opens protocol support (sockets, serial,
datagram,…)

•
Runtime binding to protocol

J2ME generally designed as a “client”

However:

•
Can be a Datagram server

•
Interfaces exist for socket serving


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“Designing for small places”

Device resources limit OO design

•
Use objects judiciously
–

consider patterns like Flyweight

•
Use lazy instantiation where feasible

Design tradeoffs:

•
Classes, methods (encapsulation vs space)

•
Inheritance (saves space, increases cpu)

•
Names (maintainability vs space)

•
Use an obfuscator

Optimizations

•
Reuse objects; avoid needless re
-
instantiation

•
StringBuffer vs String

•
Use String wrappers when hashing


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Devices

RIM 5180

Nextel

I85s

Nokia 9120

Kyocera

Sprint


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What is it?

Lightweight wireless platform for Mobile to Mobile
(M2M) collaboration

•
Every Peer is a client, server and router

Enables rapid development

•
Easy, low cost entry

•
Provides API for locating, communicating with and sharing
services between groups/peers

•
Supports Web
-
enabled start
-
up and authentication

Open standards
-
based

•
Web Services, JXTA

•
XML

Built for wireless Java

•
J2ME (MIDP/CLDC)

•
Personal Java

•
CVM & Foundation Profile


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Why IVY

Growing demand for P2P applications

•
Groove Networks

•
Games, Instant messaging

•
Napster, GNUtella

•
Mesh Networks

Technology is available

•
Programmable, wireless devices

•
Nextel’s I85

•
RIM’s 5820 J2ME/GPRS support

•
Nokia 9210 (personal java and MIDP)

•
RIM 8150

•
Over the air provisioning

•
Investment in 2.5G infrastructure

Network providers want to increase data usage


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What & Why not JXTA?

What is JXTA

•
www.jxta.org

•
Mainly 6 protocols

Is IVY compliant with JXTA? No,
but almost

•
Uses JXTA protocols

•
JXTA requires TCP/IP and/or HTTP;

•
Datagram/UDP not supported

Why use Datagrams

•
Optimal for wireless networks.

•
Network providers use datagrams under WAP, HTTP and
sockets.

Why not use JXME (JXTA’s J2ME project)

•
Very early stages

•
Uses TCP/Http and centralized “super server”

•
Polling architecture. Not really P2P?


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JXTA

High
-
level abstraction

•
Hides complexity of physical network

•
Single uniform addressability for all peers

•
Simple model for discovery, addressing and service sharing

Based on JXTA
–

6 protocols

•
Peer Discovery

•
Peer Resolver

•
Peer Information

•
Peer Membership

•
Pipe Binding

•
Endpoint routing

XML messages

•
Text

•
Binary

1 Request & 1 Response

•
Stateless

Peer

Advertisement

Endpoint

Pipe

Peer

Peer

Group

Service


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Conceptual Architecture

APIs

•
Peer , groups

•
Services, Ads

•
Pipes

Protocols & Formats

•
JXTA XML & binary

•
SOAP/WSDL

Messages

•
Full duplex

•
Datagrams

•
HTTP,HTTPS

Cross Platform

•
J2ME

•
J2SE

Messages
Protocols and Formats
Pipes
Services
Ads
Peers and Groups
User Interface
Web Svcs
(soap,wsdl)

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Service
-
oriented Architecture


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Key Design Drivers

Network connectivity

•
Asynchronous API with listeners

•
Datagrams with reliable upper level

Minimize server dependency

•
Peer Group advertisements

•
Get credentials

Small footprint

•
Implement “needed” protocols

•
30K un
-
obfuscated

JXTA compliant



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Java Packages

Ivy.api
–

Just interfaces and factories for
services and abstracts (pipes, messages,
peers, endpoints)

Ivy.impl
–

Implementations for the ivy.api
package

Ivy.util
–

constants and static methods

Ivy.net
–

Differs whether J2ME or J2SE

Ivy.exception


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Contact Information


Digital Focus, Inc.

13825 Sunrise Valley Drive

Suite 220

Herndon, VA 20171

www.digitalfocus.com


Tom Whitcomb

Chief Technology Officer

tom.whitcomb@digitalfocus.com

703.561.5884

or

Dave Hoffman

Vice President

dave.hoffman@digitalfocus.com

703.561.5963