ejb et ws (montreal jug - 12 mai 2011)

EJB and SOAP WS

Par Romain Rocèspour le Montréal JUG

About me

Teacher at Supinfo Montreal

Romain Rocès

Blue belt on BlackBelt Factory

romain.roces@gmail.com

Romain Rocès

Concept

Concept

Provides different services (Session Bean), communicates with another application (Message Bean), saves information (Entity Bean).

EJB regroups several concepts

Just like a brain, EJB is the center of the application.It proposes many functions.

Version 3

The previous version (2.1) was too complex

The version 3.0 tends to simplification :Less steps, less classes, less configurationImprovements from Java EE 5

AnnotationsGenericsJava Persistance API

Concepts remain the same, but Sun integrated many ideas from popular open-source projects like Spring or Hibernate.

Application servers

WebLogic, by BEA

Oracle Application Server, by Oracle

JBoss, by RedHat

GlassFish, by Sun MicroSystems

EJB session

Singleton, Stateless, Stateful

Facade pattern

The Session Bean acts as a “facade”.It's the client's interlocutor

Client accessDifferent clients can call the Session Bean methods if they possess its interface

Session Bean deployed on a serverWeb application

Desktop application

InterfaceImplementation

Session Bean Local

Set @Local on the interface (not mandatory)

Used when the client is deployed in the same virtual machine

Example :A Web application deployed in the same server as the Session Bean

Advantage :Resource-friendlyMore secure

Disadvantage :Local scope

Session Bean Local

Local interfaces are not mandatory

@Statelesspublic class HelloServiceBean { public String sayHello(){ return "Hello World"; }}

Session Bean RemoteSet @Remote on the interface

Used when the client is located in a different virtual machine

Example :A web application deployed in a different server than the Session BeanA rich-client

Advantage :Open on the network

Disadvantage :Consumes more resources (uses RMI)Security

Session Bean Remote

@Remotepublic interface HelloService {public String sayHello();}

@Statelesspublic class HelloServiceBean implements HelloService{ public String sayHello(){ return "Hello World"; }}

Interface

Implementation

Stateless modeA Stateless Bean is not bound to any client

getPlaces() getPlaces()getTrips()

Exemples :Retrieve a list of productsHelloService

Advantage : Resource-friendly

Stateless mode

@Statelesspublic class HelloWorld { public String sayHelloTo(String name){ return "Hello " + name; }}

Stateful mode

getPlaces() getPlaces()

getTrips()

A Statefull Bean is bound to a client

Exemples :CartOrderService

Advantage : Impact on server performance

Stateful mode

@Statefulpublic class OrderService { public void setName(String name){…}; public void setAddress(String address){…}; public void buyDog(){…}; …}

Singleton modeOne Singleton Bean per JVM

Exemples :CounterCache

Advantage :Resource-friendlyOne instance

Disadvantage :One instance

Singleton mode

@Singletonpublic class Counter { private int i = 0; public int getCount(){ return ++i; }}

Asynchronous calls

How to have asynchronous call in EJBs ?

Threads don't integrate well

@Asynchronous

Method returns void or java.util.concurrent.Future<T>

Asynchronous calls@Statelesspublic class HelloWorld { @EJB MailManager mailManager; public String sayHelloTo(String name){ mailManager.sendMail(); return "Hello " + name; }}

@Statelesspublic class MailManager { @Asynchronous public void sendMail(){ ... }}

Timer Service

Programmatic and Calendar based scheduling« Last day of the month »« Every five minutes on Monday and Friday »

Cron-like syntaxsecond [0..59], minute[0..59], hour[0..23], yearDayOfMonth[1..31]dayOfWeek[0..7] or [sun, mon, tue..]Month[0..12] or [jan,feb..]

Timer Service

@Statelesspublic class WakeUpBean { @Schedule(dayOfWeek=“Mon-Fri”, hour=“9”) void wakeUp() { ... }}

Unit Test

JUnit

Not in EJB context

@Test public void myTest(){ StatelessBean statelessBean = new StatelessBean(); statelessBean.getCounter(); }

JUnit

With EJB context : embedded glassfish

@Testpublic void myTest() throws NamingException{ EJBContainer createEJBContainer = EJBContainer.createEJBContainer(); StatelessBean statelessBean = (StatelessBean)container.getContext() .lookup("java:global/classes/StatelessBean"); statelessBean.getCounter(); container.close();}

Unit Test

Cactus is a simple test framework for unit testing server-side java code (Servlets, EJBs, Tag Libs, Filters, ...).

The Ejb3Unit project automates Entity and Session bean testing outside the container for the EJB 3.0 specification.

Client connection

lookup & @EJB

EJB connection with lookup

The client needs the JNDI context to connect to the server.

The client also needs the Session Bean interface

Retrieve the Session Bean with a lookup()

Then it's possible to call methods from the Bean

Context context = new InitialContext(); HelloService hello = (HelloService) context.lookup(HelloService.class.getName()); System.out.println(hello.sayHello());

The Session Bean will send you a message !

EJB connection with lookup

GlassFish parametersjava.naming.factory.initial=com.sun.enterprise.naming.SerialInitContextFactoryjava.naming.factory.url.pkgs=com.sun.enterprise.namingjava.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl

jndi.properties file example

JBoss Parametersjava.naming.factory.initial=org.jnp.interfaces.NamingContextFactoryjava.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfacesjava.naming.provider.url = 127.0.0.1:1099

EJB injection

In the same JVM, it's not necessary to do a lookup()

Obtain a Session Bean with resource injection

Used in other EJBs, web applications

public class ClientServiceBean implements ClientService {

@EJB private OrderService orderService;

...}

Soap WS in EJB moduleAdd @WebService and @Stateless annotation on a classIt run !

@WebService@Statelesspublic class MyBeanPublic { @WebMethod public String helloWorld() { return null; }}

Default WSDL address : http://localhost:8080/MyBeanPublicService/MyBeanPublic?wsdl

Soap WS in EJB moduleNow, we use our EJB @stateless in our SOAP WS.

@WebService@Statelesspublic class MyBeanPublic {

@EJB private MyBeanLocal ejbRef;

@WebMethod public String helloWorld() { return ejbRef.helloWorld(); }}

Soap WS in EJB moduleExemple with NetBeans 7

EJB entity

Persistence UnitThe persistence unit makes the link between your application and a DataSource

Persistence Unit

Different providers

Hibernate (use by default in JBoss)

TopLink (use by default in Glassfish v2)

EclipseLink (use by default in Glassfish v3)

Persistence Unit

<?xml version="1.0" encoding="UTF-8"?><persistence version="2.0" ...> <persistence-unit name="montrealjugPU" transaction-type="JTA"> <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

<jta-data-source>jdbc/firone</jta-data-source>

<exclude-unlisted-classes>false</exclude-unlisted-classes> <properties> <property name="eclipselink.ddl-generation" value="create-tables"/> </properties> </persistence-unit></persistence>

persistence.xml

Persistence Unit

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE resources PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Resource Definitions//EN" "http://glassfish.org/dtds/glassfish-resources_1_5.dtd"><resources> <jdbc-connection-pool ...> <property name="serverName" value="localhost"/> <property name="portNumber" value="1527"/> <property name="databaseName" value="firone"/> <property name="User" value="firone"/> <property name="Password" value="firone"/> <property name="URL" value="jdbc:derby://localhost:1527/firone"/> <property name="driverClass" value="org.apache.derby.jdbc.ClientDriver"/> </jdbc-connection-pool> <jdbc-resource enabled="true" jndi-name="jdbc/firone" object-type="user" pool-name="derby_net_firone_fironePool"/></resources>

glassfish-resources.xml

EntityManager in EJB

Obtain an EntityManager with injection

@Statelesspublic class DAO {

@PersistenceContext(unitName="montrealjugPU") protected EntityManager em;

public void createCat(Cat cat){ em.persist(cat); }}

EJB message

Java Message Service

JMS presentation

The same since 2002

Used when some information should be exchanged between

Two applications : point-to-point modelSeveral applications : publish and subscribe model

Asynchronous system : messages are received when the client request them

Similar to a mail system

Queue mode

Topic mode

Messages

There are three different types of messages

TextMessage to send simple text

ObjectMessage for a serialized object

MapMessage contains a map with strings as keys and objects as values

Send a message

In order to send a message, we have to:

Reclaim required objects via JNDIA ConnectionFactory (service provider)A Destination (Queue or Topic)

Create a Connection using the factory

Open a Session using the connection

Create a MessageProducer

Send the message

Send a message

Context ctx = new InitialContext();ConnectionFactory connectionFactory = (ConnectionFactory) ctx .lookup("ConnectionFactory");Destination destination = (Destination) ctx.lookup("queue/StockValue");

Connection cnx = connectionFactory.createConnection();

Session session = cnx.createSession(false, Session.AUTO_ACKNOWLEDGE);MessageProducer producer = session.createProducer(destination);

TextMessage message = session.createTextMessage();message.setText("Your'microsoft' stock has been sold !");producer.send(message); cnx.close();

Receive a message

Two ways to receive a messageBlocking, waiting for a messageNon-blocking, using a message listener

A message listener is similar to an event listener : it "subscribes" to a particular destination and receives messages each time there's a new one

Receive a message

Blocking modeMessageConsumer consumer = session.createConsumer(destination);// Retrieve a single messageMessage receivedMessage = consumer.receive();

Non-blocking mode, using a listenerMessageConsumer consumer = session.createConsumer(destination);// Set the listenerconsumer.setMessageListener(new MessageListener() { public void onMessage(Message message) { // Will be called each time a message is received}});

Receive a message : Message Driven Bean

A Message Driven Bean is a specific component for receiving messages

Annotation used is @MessageDriven

Destination name and type are declared in the annotation

Implements javax.jms.MessageListenerMethod public void onMessage(Message m)Called at the moment of receipt

Receive a message : Message Driven Bean

@MessageDriven( mappedName="queue/StockValue", activationConfig = {@ActivationConfigProperty( propertyName = "destinationType", propertyValue = "javax.jms.Queue")})class MyDrivenBean implements MessageListener { public void onMessage(Message message) {TextMessage textMessage = (TextMessage) message;System.out.println(textMessage.getText());}}

Merci de votre attention

Sources

Supinfo : www.supinfo.com

ParisJUG : www.parisjug.org

License

http://creativecommons.org/licenses/by-nc-sa/2.0/fr/