JavaOne 2007 - TS4721

Implementing Java EE Applications using Enterprise JavaBeans (EJB) 3 Technology: Real World Tips, Tricks, and New Design Patterns Fabiane Bizinella Nardon CTO Zilics www.zilics.com TS-4721 Edgar Silva Solutions Architect JBoss, a division of Red Hat www.jboss.com

Agenda ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

EJB 3 Technology New Features ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

EJB 3 technology in the real world ,[object Object],[object Object],Enterprise Content Management for a Government Agency Project: Human Resources Information system for an IT Company Project: Healthcare Information Systems for Healthcare Providers in Brazil and Angola Project: Financial Services Sales System for a multi-national bank Project:

Keep the defaults in mind! ,[object Object],[object Object],[object Object],[object Object],[object Object],Session Beans Pitfalls

Some pitfalls still exists ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],@ApplicationException(rollback=true) public class MyException extends Exception ...

Entity Beans Pitfalls ,[object Object],Keep the defaults in mind @Transient public String getAProperty{ … } ,[object Object],[object Object],[object Object],[object Object]

Lazy loading relationships and tiers ,[object Object],[object Object],[object Object],[object Object],[object Object]

Detached Entities and Lazy Loading public Patient getPatientData(PK id) { Patient p = entityManager.find(id); p.getDocuments().size(); // O bjects detach automatically when they // are serialized or when a persistence context ends. // The specification does not define any way to // explicitly detach objects. } public void updatePatient(Patient p) { Patient p = entityManager.merge(p); }

Retrieving meta-information ,[object Object],[object Object],public String getPrimaryKey(Class clazz, EntityManager em) { if (em instanceof HibernateEntityManager ) { SessionFactory factory = ((HibernateEntityManager)em) .getSession().getSessionFactory(); String pk = factory.getClassMetadata(clazz) .getIdentifierPropertyName(); } }

Message Driven Beans Pitfalls ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Using Dependency Injection ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Using Dependency Injection (cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Using Interceptors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Processing annotations in runtime ,[object Object],[object Object],[object Object],public Object findEagerFetch(PK pk, Class object) { // find properties with lazy fetch relationship // annotations and // build dynamic eager fetch query } ,[object Object]

Old and New Design Patterns ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Session Fa çade ,[object Object],@Stateless public class PatientFacadeBean implements PatientFacade { @PersistenceContext(unitName=”PatientPC") private EntityManager em; public void addPatient(Patient p){ em.persist(p); } public List<Patient> findPatients() { List<Patient> result = em.createQuery( "SELECT OBJECT(p) “+ “ FROM Patient p").getResultList(); return result; } }

Value Object / Data Transfer Object ,[object Object],[object Object],[object Object]

Fast Lane Reader ,[object Object],[object Object]

Business Delegate ,[object Object],[object Object],[object Object]

Value List Handler ,[object Object],[object Object],Client ValueListHandler Page SessionBean Entity <<getData>> <<iterates>> <<providesData>> 0..n <<instantiates>>

Business Rule Interceptor ,[object Object],[object Object],public void savePatientVisit(Visit v) { if(!currentUser().worksForHospital(v.getHospital) { throw new SecurityException( “can’t save data”); } if(v.getHospital().equals( “H1”)) { runHospital1BusinessRule(v); } save(visit); }

Business Rule Interceptor (Cont.) ,[object Object],@Interceptors({SecurityInterceptor.class, CustomRulesInterceptor.class}) public void savePatientVisit(Visit v) { save(visit); } ,[object Object]

Entity View ,[object Object],[object Object],SELECT NEW br.com.zilics.PatientView(p.id, p.name) FROM Patient p WHERE p.name LIKE :name

Eager Loading Parameter ,[object Object],[object Object],public Object findEagerFetch(PK pk, Class object, boolean eagerLoadOneToOne, boolean eagerLoadOneToMany, int maxFetch ); public Object findEagerFetch(PK pk, Class object, String… relationships );

Data Change Observer ,[object Object],[object Object],[object Object],[object Object],@EntityListeners(QuoteObserver.class) public class Quote implements Serializable {…} public class QuoteObserver { @PostPersist public void newQuoteAvailable(Quote q) { EventSystem.alert(q.getName(), q.getValue()); } }

Exportable Method ,[object Object],[object Object],public Proposal getProposalByCode(String code) { return em.find(Proposal, code); } @WebMethod public String getProposalByCodeAsXML(String code) { return XmlTransformer().marshal ( getProposalByCode (code)); }

Exportable Service Broker ,[object Object],[object Object],[object Object],[object Object]

Transition impact for the developers ,[object Object],[object Object],[object Object],[object Object]

Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

For More Information ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Q&A ,[object Object],[object Object]

JavaOne 2007 - TS4721

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