Beyond J2EE 1.4 Peter Trger Hasso-Plattner-Institute University of - PowerPoint PPT Presentation

Beyond J2EE 1.4 Peter Tröger Hasso-Plattner-Institute University of Potsdam

Agenda � J2EE Future � JSR Process, EE 5, EJB 3 � Sun AppServer 9, JBoss 5, OpenEJB � Dependency Injection & Inversion of Control � Hivemind, Spring, PicoContainer, Plexus, Yan, Avalon, Tapestry � Object-relational persistence � Hibernate, XMLBeans, Castor � Servlet-based frameworks - Struts � Sources: Sun JSR & GlassFish material, Martin Fowler homepage, different project sites

JSR Process � Java Community Process (JCP) for development of specifications (since 1995) � Initiation (approved by executive committee) � Early draft (for review by the public domain) � Public draft (reference implementation, compatibility toolkit) � Maintenance (document updates) � Java Specification Request (JSR) � Proposed and final specifications for Java platform � Review / approval process

Java EE 5 Platform � Next version of J2EE platform � Latest versions of Java technology � Enterprise JavaBeans (EJB) 3.0 (JSR-220) � JavaServer Faces (JSF) 1.2 (JSR-252) � Servlet 2.5 � JavaServer Pages (JSP) 2.1 � Java API for Web Services (JAX-WS) 2.0 (JSR-224) � Web Services Metadata (JSR-181) � Java Architecture for XML Binding (JAXB) 2.0 (JSR-222) � Java Persistence 1.0 (JSR-220) � Common Annotations 1.0 (JSR-250) � Streaming API for XML (StAX) 1.0 (JSR-173)

Java Enterprise System Application Platform Suite Zur Anzeige wird der QuickTime™ Dekompressor „TIFF (LZW)“ benötigt.

Java EE 5 Major Features � Simplified web service support � More web service standards support � Simplified EJB development � New persistence API � Easier web applications with JavaServer Faces � Most specs available for review � Spec at Proposed Final Draft state - Q4 2005 � Java EE 5 SDK Beta release - Q1 2006 � Java EE 5 Final release - Q2 2006

Project GlassFish � Open Source Java EE 5 Application Server � Sun AppServer Platform Edition 9 � Open access to code and binaries � Integrates with NetBeans, Sun Java Studio Enterprise, Eclipse � Standard Edition � Advanced security, self-managing, self-healing � Clustering, multi-machine administration � Enterprise Edition � Support for high availability

Grizzly HTTP Framework � Highly scalable HTTP path � Thousands of connections with few Java threads � Uses lower level Java NIO primitives � Easy-to-use, high-performance APIs for socket communication � Brings non-blocking sockets to the HTTP processing layer � Integrates with current Apache Tomcat HTTP Connector architecture (Tomcat 3,4,5) � Replaces Apache Tomcat Coyote HTTP front-end and thread pool � High-performance buffers and parsing classes

Fast Infoset � Optimized Binary XML transport mechanism - fast web services � Transparently used by web service communication stack � TS-7187

GlassFish JBI Integration � Java Business Integration (JBI) standard � JSR 208 � SOA-way of Enterprise Application Integration � Normalized Message Router � OpenESB - Enterprise Service Bus product, out-of-box support for SOAP and JMS � Java EE web services (EJBs and Servlets) are automatically enabled in Normalized Message Router � JAXWS communication can be routed in-process to Normalized Message Router

EJB 3.0 � Coordinated in JSR 220 � POJO-based programming (Plain Old Java Object) � No more Home interfaces � Backward compatibility � Extensive use of annotations, reduced need for deployment descriptors � Specification of default behavior, reduces configuration overhead � Dependency injection with annotations � Improved EJB-QL (Update, Delete, Inner / Outer Join, SQL) � Manager concept for entity bean POJOs � Less checked exceptions � Improved performance Read-only beans � Relationship pre-fetching �

Annotations as Descriptors Only RUNTIME annotations used � Available in class file, read by runtime, simplifies container development � Deployment descriptors overwrite annotation configuration � Annotation for business interface and references � Business interfaces are optionally generated � Lifetime management through annotated functions � (@PreDestroy, @PostConstruct) @Stateless @Remote public class HelloWorldBean { public String getHello() { return „Hello World“; } @PreDestroy cleanUp() { // logic before destruction of the instance }}

EJB 3 Example @Stateless public class PayrollBean implements Payroll { @Resource DataSource empDB; public void setBenefitsDeduction (int empId, double deduction) { ... Connection conn = empDB.getConnection(); ... } ... } ---------------------------------------------------- @EJB ShoppingCart myCart; Collection widgets = myCart.startToShop(“widgets”);

EE 5 Web Service Example @WebService(name=”MySimpleWS”); public class RandomClass { @WebMethod public String sayHello (String s) {...} public void unpublished() {...} } ------------------------------------------------------- @WebServiceRef ( wsdlLocation= ” http://localhost:8080/SayHelloService?WSDL ”);) static javaone.SayHelloService wsService; public static void main(String[] args) { javaone.SayHello wsPort = wsService.getHello(); wsPort.sayHello(“FOSS.in Attendees”); }

AOP through Interceptors public class MyInterceptor { @AroundInvoke public Object myInterceptionMethod( InvocationContext inv) throws Exception { // Code for advice return inv.proceed(); } @Interceptors ({„org.example.MyInterceptor"}) public class HelloWorldBean {...}

Java 6 (“Mustang”) � Coordinated in JSR 270 � Development snapshots / sources available � New bytecode verifier for improved performance � JFC / Swing / AWT improvement, Java 2D API, better internationalization � Java Compiler API (JSR 199) � XML and Web Services (XML Signatures, JAX-WS 2.0, JAXB 2.0, JDBC 4.0, JMX 1.3) � Set of improvements for Java 5 features � Sources available

Open Source Efforts beyond J2EE 1.4 � Huge amount of activities to build alternatives to the J2EE 1.4 technologies � Interfaces are good abstraction, but where does the interface implementation class come from ? � Heavyweight complexity � Component wiring as main problem � lightweight containers

Component Wiring – The Problem public interface MovieFinder { List findAll(); class MovieLister { private MovieFinder finder ; public MovieLister() { finder = new ColonDelimitedMovieFinder ("movies1.txt"); } public Movie[] moviesDirectedBy(String arg) { List allMovies = finder.findAll(); for (Iterator it = allMovies.iterator(); it.hasNext();) { Movie movie = (Movie) it.next(); if (!movie.getDirector().equals(arg)) it.remove(); } return (Movie[]) allMovies.toArray(new Movie[allMovies.size()]); } }

Component Wiring Through Dependency Injection � Assembling of ‚plugin‘-style components through „ Inversion of Control“ (IoC) � Separate assembler object injects an implementation into the plugin-using component � Prevents tight coupling of specific interface implementation and interface users � „Dependency Injection“ pattern

Dependency Injection – Constructor Injection � Parameterized constructor of interface user takes injected implementation � Configuration code about injected objects � In different class (PicoContainer project) � In XML file (NanoContainer project) � Client asks IoC framework for instance public void testWithPico() { MutablePicoContainer pico = configureContainer(); MovieLister lister = (MovieLister)pico.getComponentInstance(MovieLister.class); Movie[] movies = lister.moviesDirectedBy("Sergio Leone"); ...}

PicoContainer Example class MovieLister... public MovieLister(MovieFinder finder) { this.finder = finder; } class ColonMovieFinder... public ColonMovieFinder(String filename) { this.filename = filename; } private MutablePicoContainer configureContainer() { MutablePicoContainer pico = new DefaultPicoContainer(); Parameter[] finderParams = { new ConstantParameter("movies1.txt") }; pico.registerComponentImplementation ( MovieFinder.class , // the interface ColonMovieFinder.class , // the implementation finderParams ); pico.registerComponentImplementation(MovieLister.class); return pico; }

Dependency Injection – Setter Injection � Assembler hands dependency instances through a setter method after instantiation � No atomic setting like with constructor injection � Main concept in the Spring framework public void testWithSpring() throws Exception { ApplicationContext ctx = new FileSystemXmlApplicationContext("spring.xml"); MovieLister lister = (MovieLister) ctx.getBean("MovieLister"); Movie[] movies = lister.moviesDirectedBy("Sergio Leone"); }