Blackberry and Java

8/8/2019 Blackberry and Java

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Introduction to Java and J2ME

Development

Using BlackBerry Development Tols

Platform for Developing Applications


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Agenda

Introduction to J2ME Overview of J2ME architecture & APIs

Toolkits for Application Development

Sample Application

J2ME: Advanced Topics Best Practices

Application Deployment

MIDP 2.0


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J2ME Architecture

A standard subset of the Java (J2SE) class libraries

to enable Java applications to run on small computingdevices

Defines a Virtual Machine called the KVM Optimized for use on small devices

Recognizes that small devices vary greatly in theirnature

J2ME defines Configurations (baseline) and Profiles(application-specific)

Target Devices: Mobile phones, PDAs, Car navigationsystems, embedded devices


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J2ME CLDC 1.0 Configuration

Configurations

Core set of classes that provide the minimal features that alldevices in this configuration must support

Connected Limited Device Configuration

Defines configurations for devices with: Variable network coverage

Slow processing speed

Limited memory

Target Devices: Mobile phones

Low-end PDAs


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J2ME CLDC 1.0 Configuration

CLDC 1.0 provides the following Java libraries:

Library Example

HttpConnection

StreamConnection

javax.microedition.io

CLDC-specific input/output library

Vector

Random

java.util

Standard java utilities library

String, Byte

Thread

java.lang

Standard java extended language

library

InputStreamOutputStream

java.io

Standard java input/output library


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J2ME MIDP 1.0 Profile

Profiles

Classes geared towards specific types of applications

(uses of a device) Mobile Information Device Profile

Built on top of CLDC 1.0, with extra APIs for: Defining and controlling applications

Displaying text and graphics

Persistent data storage Network connectivity

Applications built using MIDP/CLDC are referred to asMIDlets

MIDlets sharing code/data are referred to as MIDlet suites


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J2ME MIDP 1.0 Profile

MIDP 1.0 provides the following Java libraries:

Library Example

RecordStorejavax.microedition.rmsRecord Management System (data

storage)

Screen, Graphics

Textbox,CommandListener

javax.microedition.lcdui

LCD user interface library

MIDletjavax.microedition.midlet MIDP application library


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BlackBerry J2ME API Extensions

All BlackBerry Java devices support CLDC & MIDP 1.0

RIM has developed extensions to the standard J2ME libraries toenable more flexible and customized integration with BlackBerryfeatures

Developers can write new applications for BlackBerry usingthese Java APIs

Java APIs for BlackBerry enable you to develop custom clientapplications that provide:

Robust & customizable User Interface

Persistent Data Storage on the handheld

Event Listening & System interfaces

Secure wireless transport via HTTP(S) and Email


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For more advanced applications:

Integration with BlackBerry Email & PIM

applicationsBulk data loading and backup/restore via

Desktop Manager

Always-on & Auto-started background

threads & PUSH


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Library Example

ResourceBundle

Locale

net.rim.device.api.i18n

Internationalization support

Array, HashTable

StringUtilities

net.rim.device.api.util

Extended utilities library

EditField, ListField

Menu

net.rim.device.api.ui.component

UI objects that reside within a container

MainScreen, FullScreen

PopupScreen

net.rim.device.api.ui.container

UI objects that contain other elements

Screen, Graphics

UiApplication

net.rim.device.api.ui

Fundamental user interface library

TrackwheelListener, KeyListener,Application

net.rim.device.api.system

BlackBerry system-level library


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J2ME Architecture for BlackBerry

BlackBerry Handheld (Radio, LCD, RAM, Keyboard etc.)

Java Virtual Machine

J2ME APIs(MIDP & CLDC)

APIs for BlackBerry

(UI, System, compression,

etc.)

Java Applications


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J2ME Wireless Toolkit

Supports development of MIDP/CLDC applications

Includes an environment that allows for compilation,execution and packaging of applications

Can be integrated with a compatible IDE (eg. SunONE Studio Mobile Edition) that allows for debuggingand editing source code and emulation

J2ME Wireless Toolkit 2.0 supports MIDP 2.0applications


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BlackBerry JDE

Custom client applications are built with theBlackBerry Java Development Environment (JDE)

BlackBerry JDE v3.7

Based on Java 2, Micro Edition (J2ME): MIDP/CLDC 1.0

Full featured Integrated Development Environment (IDE)with Handheld Simulators, MDS Simulator, Debugging &Optimization tools

Robust Java API set

BlackBerry JDE v4.0 Release date: September 2004

MIDP 2.0 and CLDC 1.1 support

Enhanced BlackBerry APIs


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Sample Application

1. Launch Application 2. List of Customers 3. Create New Call Report 4. Enter Details & Submit

BlackBerry

Server

Web/App

Server

Data Store


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Sample Application

Data StoreWeb/App

Server

HTTP

http://myWebServer/bb/callReport


BlackBerry

Server


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Sample Application

Data Store

HTTP Interface

(Receive Data)

Connector Interface

(ODBC, J2EE, .NET)

App Logic &

User

Management

J2EE/.NET

ODBC/SQL

Web/App

Server

HTTP

http://myWebServer/bb/callReport


BlackBerry

Server


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J2ME Best Practices

Use Device Resources WiselyPlan Ahead!!

Minimize application size Limit the number of features

Object design create single objects for common tasks and reuse them

Place resource data on the server Large resources that each user will only require a subset of

Minimize run-time memory use Use scalar types (int, boolean) instead of objects (String, Integer)

Dont depend entirely on the garbage collector

Avoid creating a lot of objects quickly

Reuse objects Move computation to server

Perform data filtering, sorting, etc. on the server before sending it to thedevice

Completely process and manipulate data as needed before indicating to theuser that new data has arrived. This hides latency from user


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J2ME Best Practices

Code with Performance in Mind Use local variables

Generally quicker to access local variables than class members

Use threads for lengthy operations ( > than 1/10 second) Stop the operation from blocking the main UI thread

Set appropriate access and declaration type Declare members as privatewhenever possible

Declare classes as finalif they will not be extended

Carefully use staticand final understand the performance impacton both classand primitivetypes

Carefully optimize loops and mathematical operations

See the JDE Developer Guide for more performance tips


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J2ME Application Deployment

MIDlets are packaged into a JAR file

On BlackBerry, JAR files are converted to CODfiles

JAR file includes: Manifest

Java classes

Resource files

JAD file accompanies JAR Contains description (attributes) about MIDlet

Allows application manager to verify the MIDlet issuited for device before downloading


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JAD File Example

MIDlet-Name: CallReporter

MIDlet-Version:1.0.0

MIDlet-Vendor: RIM

MIDlet-Description: Custom CRM Application

MIDlet-Jar-Size: 15289

MIDlet-Jar-URL: www.blackberry.com/download/CRM


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Blackberry and Java