javaee-azrulmadisa

8/9/2019 JavaEE-AzrulMadisa

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Java EE Midlife Crisis

ByAzrul [email protected]

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at s appen ng o ate

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Oracle acquisition of Sun The pathetic prophets

Would somebody please think of thechildren!!

Onslaught of new languages/technologies Is Java in midlife crisis?

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a s ory eac es us

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Java will always adapt

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The simple fact remains, then: Java, theplatform, the ecosystem, the environment and

,far from the Abyss of Irrelevancy as any of theother languages or platforms currently in usetoday Ted Neward

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Old and reliable Patterns Distributed computing

Transactionmanagement

Load balancing

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New

Contexts and DependencyInjection (CDI)

Java EE + Other JVM languages

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Context and De endenc

Injection

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Contexts and DependencyInject - CDI

JSR-299

e-safe DI AOP

and Eventing Use annotation a

whole lot to achievea whole lot more

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CDI vs. the world

more typesafe than Seam, morestateful and less XML-centric than

,application capable than Guice Gavin

King, JSR-299 spec lead

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CDI Dependency Injection (DI) Typesafe DI with qualifier

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CDI DI example

@MyService(PRODUCTION)public class ProductionShoppingCart implements

ShoppingCart{}

@MyService(MOCK)

public class MockShoppingCart implementsShoppingCart{}

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CDI DI example Injecting a shopping cart to a servlet

public class Ecommerce extends HttpServlet {

@Inject @MyService(MOCK) ShoppingCart shoppingCart;protected void doGet( ){

//use shopping cart

}}

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CDI Eventing Light weight eventing Decouple sender and recipient

Can use JMS as a broker

POJO POJO

POJO

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CDI Eventing Create the object to be send

private String content=Yap! Yap! Yap!;

}

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CDI Eventing Create a sender

public class Women {

@Inject Event eventUtility;public void say(){

MyMessage myMessage = new MyMessage();

eventUtility.fire(myMessage);

}}

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CDI Eventing

Create a listener

public class Men {

public void listen( @Observes MyMessage myMessage){Logger.log(Message:"+myMessage.getContent());

}

}

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Challenge

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Java Enterprise Application In 1 week

Make it work

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Problem

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Enterprise Job Scheduling App

At a scheduled time

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Enterprise Job Scheduling App Examples:

Telcos

Every week, all usage data need to be processed.

Banks

Every night, all credit card applications for the day needto be processed

Insurance Underwriting for new applications need to be done every

3 working days

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How it works Telco example

Step1Aggregate all usage data

for this month

Scheduler

Business Process

Step2

Step3

For each user, create aninvoice

Send all invoices for printing

At 12:00 midnightEvery 15th of a month

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Challenges in creating a scheduler

Scheduler need an interface Preferable web

Scheduler should be loosely coupled from the

BP BP can change without affecting the scheduler Vice-versa

Scheduler should use standards as much aspossible Standard scheduling expression

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Challenges in creating abusiness process BP needs to be scalable

but cannot be truly stateless since BP arestateful by nature

BP needs to be somewhat standard The standard, BPEL, is too web-services centric

BP needs a decent tool BP is loosely coupled from jobs

Jobs can change without affecting BP BP can change without affecting jobs

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Challenges in creating a job

Job need to be asynchronous but need to be chained i.e. fire and forget cannot be

used here

Job need to be simple to create

Tool support is needed Job need to be a standard artefact

Easier to recruit people who knows standard stuff

Testability of a job is crucial

Job need to be as POJO as possible Job contain business logic

Transaction is crucial

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Challenges in the system as awhole Load-balancing capable

Transactional

Rollback / redo Use standard solution wherever possible

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Answering the challenge

----------------Scheduler

-------------------------------------BusinessProcess-------------------------------------my_business_process.jpdl.xml

Web

HTTP

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Answering the challenge transactional jobs

-------------------BusinessProcess

---------------

JMS

Step1

Step2

Step3

---------------Delegate

BusinessLogic

JMS

CDI Event

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Answering the challenge lightweight jobs

-------------------BusinessProcess

---------------

Step1

Step2

Step3

BusinessLogic

CDI Event

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Answering the challenge

A job:

public void handleEvent(@Observes@CDIEventSource("MyBusinessLogic") CDIEvent event) {

Map token = event.getToken();

//token = Input/Output

//do some business logic}

}

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Delivering promises

Simplicity Jobs a POJO

Business process is a plain old JPDL

Scalability

JMS and asynchronous, event based framework

Lightweight

CDI eventing

Statefulness

JBPM + Request-response pattern

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Delivering promises

Reliability Transaction all the way even in

li htwei ht mode

Java EE provided clustering/fallback JMS provided load-balancing

Scheduler

MyBP MyBP MyBP

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Delivering promises

Loose coupling CDI Event JMS exchangability without

modif in the Business Lo ic

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Conclusion

Java is old and reliable and yet new andexciting

Dont want to use the Java language,

Scala

Groovy

Anything

Java is well, alive and kicking butts really hard!

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Thanks for listening to someonewho is not yet on a midlife crisis

Azrul MADISA

[email protected]

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