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What's New in Enterprise JavaBean Technology ?

Sanjeeb SahooSr. Staff Engineer, Sun, an Oracle Company

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The following/preceding is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions.The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

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Agenda

• Introduction• Ease of Use Improvements• New Functionality

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EJB 3.0 Specification

• Goal• Ease of use• Developer productivity

• JSR (Java Specification Request) 220• Final Specification – 2006

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EJB 3.0 Specification

• Metadata via Java annotations• Only annotations• Only XML DD• Both

• Sensible defaults• POJO friendly• Simplification of bean types• No home interface• Interceptors• Entity Beans replaced by JPA

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EJB 3.1 Specification

• Goals• Continued focus on ease-of-use• New features

• JSR (Java Specification Request) 318• Final Specification – December 2009

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Ease of Use Improvements

• Optional Local Business Interfaces• Simplified Packaging• EJB 3.1 “Lite” API• Portable Global JNDI Names• Simple Component Testing

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Session BeanWith “No-interface” View

@Statelesspublic class GreetingBean {

public String greet(String msg) { return “Hello “ + msg; }}

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No-interface View Client

@EJB GreetingBean h;

...

h.greet(“bob”);

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Session Bean“Interface” View

@Statelesspublic class HelloBean implements GreetingBean { public String greet(String msg) { return “Hello “ + msg; }}

@Statelesspublic class HowdyBean implements GreetingBean { public String greet(String msg) { return “Howdy “ + msg; }}

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Interface View Client

@EJB(beanName=”HelloBean”) GreetingBean h;h.greet(“bob”);

@EJB(beanName=”HowdyBean”) GreetingBean h2;h2.greet(“sam”);

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JavaTM EE Platform 5 Packaging

foo.ear

WEB-INF/web.xmlWEB-INF/classes/ com/acme/FooServlet.class com/acme/Foo.class

foo_web.war

com/acme/FooBean.classcom/acme/Foo.class

foo_ejb.jar

foo.ear

lib/foo_common.jar

com/acme/Foo.class

WEB-INF/web.xmlWEB-INF/classes/ com/acme/FooServlet.class

foo_web.war

com/acme/FooBean.class

foo_ejb.jar

OR

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foo.warWEB-INF/classes/com/acme/ FooServlet.class FooBean.class

Simplified Packaging

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EJB 3.1 “Lite”

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Portable EJB JNDI Names

Each session bean gets the following entries :

• Globally unique namejava:global[/<app-name>]/<module-name>/<ejb-name>

• Unique name within same application java:app/<module-name>/<ejb-name>

• Unique name within defining modulejava:module/<ejb-name>

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Session Bean

@Statelesspublic class HelloBean implements Hello {

public String sayHello(String msg) { return “Hello “ + msg; }}

If deployed as hello.jar, JNDI entries are:

java:global/hello/HelloBeanjava:app/hello/HelloBeanjava:module/HelloBean

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Simple Testing : Session Bean

@Stateless@Local(Bank.class)public class BankBean implements Bank {

@PersistenceContext EntityManager accountDB;

public String createAccount(AcctDetails d){ … }

public void removeAccount(String acctID)

{ … }

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Embeddable API

public class BankTester { public static void main(String[] args) {

EJBContainer container = EJBContainer.createEJBContainer();

// Acquire Local EJB reference Bank bank = (Bank) container.getContext(). lookup(“java:global/bank/BankBean”);

testAccountCreation(bank); container.close();

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Test Client Execution

% java -classpath bankClient.jar : bank.jar : javaee.jar : <vendor_rt>.jar com.acme.BankTester

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New Features

• Singletons• Startup / Shutdown callbacks• Automatic timer creation

• Cron-like syntax

• Asynchronous session bean invocations

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Singleton

@Singletonpublic class SharedBean {

private SharedData shared;

@PostConstruct private void init() { shared = ...; }

public int getXYZ() { return shared.xyz; }

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Singleton Concurrency Options

• Single threaded (default)• For consistency with all existing bean types

• Container Managed Concurrency• Control access via method-level locking metadata

• Bean Managed Concurrency • All concurrent invocations have access to bean instance

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Startup / Shutdown Callbacks

@Singleton@Startuppublic class StartupBean {

@PostConstruct private void onStartup() { … }

@PreDestroy private void onShutdown() { … } }

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Timers

• Automatically created EJB Timers• Calendar-based Timers – cron like semantics

• Every 14th minute within the hour, for the hours 1 and 2 am(minute=”*/14”, hour=”1,2”)

• Every 10 seconds starting at 30(second=”30/10”)

• Every 5 minutes of every hour(minute=”*/5”, hour=”*”)

• 2pm on Last Thur of Nov of every year(hour=”14”, dayOfMonth=”Last Thu”, month=”Nov”)

• Every Mon & Wed midnight @Schedule(dayOfWeek=”Mon,Wed”)

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Automatic Timer Creation

@Stateless public class BankBean { @PersistenceContext EntityManager accountDB; @Resource javax.mail.Session mailSession;

// Callback the last day of each month at 8 a.m.

@Schedule(hour=”8”, dayOfMonth=”Last”) void sendMonthlyBankStatements() { ... }}

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Asynchronous Session Beans

• Control returns to the client before the container dispatches invocation to a bean instance

• @Asynchronous – method or class• Return type – void or Future<V>• “Fire and and Forget” or async results via

Future<V>

• Best effort delivery – persistent delivery guarantees are not required by spec

• Transaction context does not propagate• REQUIRED → REQUIRED_NEW

• Security principal propagates

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Asynchronous Session BeansCode Sample

@Stateless@Asynchronouspublic class SimpleAsyncEJB { public Future<Integer> addNumbers(int n1, int n2) { Integer result;

result = n1 + n2; try { // simulate JPA queries + reading file system Thread.currentThread().sleep(2000); } catch (InterruptedException ex) { ex.printStackTrace(); }

return new AsyncResult(result); }}

http://blogs.sun.com/arungupta/entry/totd_137_asynchronous_ejb_a

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References

• oracle.com/javaee• glassfish.org• oracle.com/goto/glassfish• blogs.sun.com/theaquarium• youtube.com/GlassFishVideos• Follow @glassfish