JBoss at Work JAW Motors Application Chapter 2

1
JBoss at WorkJAW Motors ApplicationChapter 2

• Jeff Schmitt
• October 9, 2006

2
JAW Motors Application

• Fictitious automobile dealership
• Each chapter progressively adds a new J2EE
  technology that solves a specific business
  problem
• Viewing cars JSP
• Storing cars (persistence) JDBC or Hibernate
• Credit check -- JMS message and JavaMail response
• Purchasing transactional support using
  Stateless Session Beans
• Sharing data between dealerships Web Services

3
JBoss Application server

• Compiled Java code runs inside JVM
• Java classes need a container to provide an
  infrastructure, a framework to handle low-level
  details
• An application server is a loosely coupled
  collection of containers (or "services") that
  correspond to the various parts of the J2EE API.
• JBoss is an open-source J2EE 1.4 standards
  compliant application server

4
Java Management ExtensionsJMX

• JBoss is a thin JMX (Java Management Extensions)
  microkernel
• JMX is a framework that allows you to interact
  with live, running code
• Start and stop services
• Gather metrics
• Change parameters
• Services that implement the JMX interface are
  called Managed beans or Mbeans
• MBeans that run inside JBoss include Log4J,
  Tomcat, Hibernate

5
Tools needed

• Java JDK J2SE 1.4 or higher
• Ant to compile, package and deploy Java code
• XDoclet to generate deployment descriptors,
  web.xml and various other J2EE configuration
  files.
• XDoclet is a combination of custom Ant tasks and
  special attributes that you include in your
  source code.

6
JAW Motors Application

• Use Tomcat servlet container
• JBoss is an application server, but includes
  Tomcat
• 3-tier application
• Presentation JSP and servlets
• Business logic EJB and MDBs
• Persistence relational database
• Components in each tier
• Highly cohesive components do only one thing
• Loosely coupled components have no dependences
  across tiers

7
Model View Controller

• View HTML, JSP, CSS and JSTL produce the screen
  contents
• Model POJO (Plain Old Java Objects), Java Beans
• Controller mediates communication between the
  view and the model -- a servlet
• Framework many design decisions already made
  for you this book is framework-neutral uses
  its own controller servlet

8
View

• carList.html
• carList-jstl.jsp with JSTL tags JSP scriplet
  defines data carList
• carList.jsp with stylesheet default.css data
  saved in pageContext

9
Model and Controller

• Model
• CarBean is a POJO, is a JavaBean
• carList.jsp uses JSP EL
• Controller
• ControllerServlet
• Action parameter indicates page indirectly
• To access carList.jsp we use lta
  hrefcontroller?actionviewCarListgt
• Controller translates actionviewCarList to
  access carList.jsp

10
JBoss Deployment

• Applicatioin Assembly
• Web Archive file a collection of presentation
  tier files (HTML, JSP, Servlets, etc)
• EAR Enterprise Archive (EJBs)
• SAR Service Archive (Web Services)
• Use jar command to bundle them into a single
  file
• Application Deployment
• Hot deployment -- While JBoss is running, copy
  the WAR, EAR or SAR file to JBOSS_HOME/server/de
  fault/deploy/
• Cold deployment stop JBoss, copy the file,
  restart JBoss this is the recommended deployment