Enterprise Architecture
Java SE / Java EE Training
Awareness
M. Reha, Enterprise Architecture
2009-04-10, v0.1
Confidential and Proprietary
AAA NCNU © 2008, 2009
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Agenda
Course #1:
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Introduction to the Java Language and the Java Platform
Course #2:
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“Hello World” Java programming example
Encapsulation, Inheritance, Interfaces
Course #3:
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Introduction to the Java EE Platform
Course #4:
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“Hello World” Java EE web application programming example
Web Tier, Business/Services Tier, Persistence Tier
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Course #1
Introduction to the Java Language and the Java Platform
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Course Objectives
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Learn about the history of Java.
> Learn about the Java Platform.
> Learn what the fundamentals of the Java language.
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What is Java?
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Is Java just a programming language?
What is the JDK?
What is Java Standard Edition (Java SE)?
What is Java Enterprise Edition (Java EE)?
What is the JVM?
What is a Java EE Application Server?
What is a Java Applet?
What is Java Swing?
What is a Java Portlet
What else?
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Java ME – Java Mobile Edition (for mobile phones / devices)
Java RT – Java Real Time (for embedded real time applications)
Java TV – Java for TV (for TV and Set Top Box applications)
Java DB – Java based RDBMS
Java Card – Java for Smart Cards
Java FX – Java building next generation RIA’s
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What is Java?
Java is a programming language!
Java used as a platform to build applications ranging from web,
desktop, mobile, and more!
JDK (for SE and EE)
Compilers, tools,
documentation for the
developer
Java EE Runtime
Implements the Java EE API’s
Java SE Runtime
Also referred to as JRE
Implements Java SE API’s
Implements Java SE for CDC
Browser
Web Pages
Portlets
Java Applet
JavaFX Applet
Java Desktop
Application
(Swing, Console,
JavaFX)
Mobile Application
and Consumer
(Java ME, JavaFX,
JavaTV)
Java EE
Application Server
WebSphere, Oracle WebLogic, JBoss, etc
Java Virtual Machine (JVM)
Java Virtual Machine (JVM)
Sun, IBM, Oracle, Apple, etc.
Nokia, Philips, Sony,
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Introduction to the Java Programming Language
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Java is a programming language originally developed by James
Gosling at Sun Microsystems and released in 1995 as a core
component of Sun Microsystems' Java platform.
The language derives much of its syntax from C and C++ but has
a simpler object model and fewer low-level facilities.
Java applications are typically compiled to byte-code that can run
on any Java virtual machine (JVM) regardless of computer
architecture.
The original and reference implementation Java compilers, virtual
machines, and class libraries were developed by Sun from 1995.
As of May 2007, in compliance with the specifications of the Java
Community Process, Sun made available most of their Java
technologies as free software under the GNU General Public
License.
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History of the Java Platform
Java SE Platform:
• JDK 1.0 released in January 1996
• JDK 1.1 released in February 1997
• J2SE 1.2 released in January 1998
• J2SE 1.3 released in May 2000
• J2SE 1.4 released in February 2002
• J2SE 5.0 released in September 2004
• J2SE 6.0 released in December 2006
• J2SE 7.0 released in end of 2010
We are here in 2002!
We have some ability to leverage J2SE 5.0
Java RI will be based on J2SE5.0
Java EE Platform:
• Java Platform Edition JPE announced in May 1998
• J2EE 1.2 released in December 1999 (peak of the .COM era)
• J2EE 1.3 released in September 2001 (end of .COM era)
We are here in 2003!
• J2EE 1.4 released in November 2003
Java RI will be based on EE 5
• EE 5 released in May 2006
• EE 6 scheduled release for the end of 2008 (approval of JCP specification)
Lots of enterprises are still on J2EE 1.3 from 2002!
The Portlet Specification was not released until October 2003.
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Java Language – Language Basics
Java is a strongly typed language. This means all variables must be declared
with a type before using.
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Example: int count = 0
• int is the type for a variable called count that is initialized to 0
Java Primitives are defined by the Java Language (and are reserved keywords)
and are very similar in syntax to the C/C++ programming language:
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byte, short, int, long, float, double, boolean, char
• There are wrapper classes for most primitive types (Integer class wraps an int)
Java Operators are special symbols that perform specific operations on one or
more operands (much like the C/C++ language):
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++ --, * /, >> <<, == !=, < >, & | ^, && ||
Java Control Flow statements for program control and decision making and are
very similar to to the C/C++ programming language:
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if else, switch, while, do while, for
• exception handling (not really flow control!)
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Java Language – Classes and Objects
Java was the first Internet “aware” and Security “aware” object orientated
programming language.
(Almost) everything declared in Java defined by a Object implemented in a
Class. One of the first main stream object oriented languages.
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Object:
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An object is a software bundle of related state and behavior. Software objects are often
used to model the real-world objects that you find in everyday life.
• Real-world objects share two characteristics: They all have state and behavior.
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Class:
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A class is a blueprint or prototype from which objects are created.
• Created by using the new Java keyword. Example: ClassA a = new ClassA();
• Unused classes are removed from memory via the Garbage Collector
• There is (in theory) no memory management coding required by programmer
Classes can inherit state and behavior from other classes through Inheritance.
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ClassA extends ClassB
Classes can define contracts with the outside world (or other classes) through
interfaces.
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ClassA implements ClassB
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Java Language – Runtime Library
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A library of classes that are included as part of the Java Standard Edition which
are implemented in ALL Java Runtime distributions (IBM, Oracle/JRockit, Sun,
etc.).
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Utility: I/O, String, Date, Time, Calendar, Internationalization, Math, Collection, …
Networking: HTTP, Cookies, TCP URL and Sockets, and UDP Datagrams, …
Database: JDBC, Prepared Statements, ResultSets, Transactions, …
Component Model: JavaBean, …
Multimedia: Sound, 2D Graphics, 3D Graphics (extension lib), …
User Interface: AWT, Swing, Applet, …
Web Services: XML, SOAP
Misc: JNI, JMX, RMI, Serialization, Logging, Zip, Regular Expressions, …
System: Threads, Concurrency (Locks, Mutex, etc), Security, JNDI, …
Deployment: Java Web Start, Java Plug-In, …
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These are all documented in the Java Development Kit (JDK)!
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Java SE 6 – JDK and JRE
Image Courtesy of Sun http://java.sun.com/javase/6/docs/
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Course #2
Example Java SE Programming
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Course Objectives
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Learn what a simple Java class looks like.
> Learn about Encapsulation.
> Learn about Inheritance and Interfaces.
> Walk through a “Hello World” console application.
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“Hello World” in the Java Programming Language
Name of Object
In Java == ObjectName.java
Also known as a Class
HelloWorld
Object
private
String
message;
Data
/ State
private int count;
Behavior
public sayHello();
/ Operations
The Objects
internal data,
attributes, or
object state
The Objects behavior,
methods, or operations
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“Hello World” in the Java Programming Language
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More “Hello World” in the Java Programming Language
Extends the behavior of
HelloWorld
HelloWorld
BaseHello
private String message;
public sayLoudHellIo();
private someUtility();
public sayHello();
private setText();
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More “Hello World” in the Java Programming Language
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Course #3
Introduction to Java EE
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Course Objectives
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Learn about the history of the Java EE Platform.
> Learn about basic technologies in the Java EE Platform.
> Learn about current trends of the Java EE Platform.
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What is Enterprise Java a.k.a. Java EE?
Java EE defines standard API’s for building web applications.
> Introduced right before the .COM era started.
> The Java EE Standard is defined by Sun and the JCP.
> There have been lots of contributions from the Open Source
Community to fill in gaps from the Java EE Standard and enrich
the capabilities for building web applications.
> A Java EE Application Server implements the Java EE Standard
and provides a platform to execute web applications. Sometimes
the Application Server vendor “enhances” the platform by adding
value added features and capabilities such as Administration
Consoles, Debugging facilities, and Monitoring.
> A Java EE Application Server is rapidly becoming a commodity
with a number of very robust and scalable open source
alternatives now available on the market.
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Introduction to the Java EE Stack?
Web Tier Technologies:
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Servlet – lowest level (above protocols and sockets) to handle HTTP request
Java Server Pages – markup (like HTML tags) to build dynamic pages
Java Standard Template Library – standard tags for conditional, loops, etc.
Java Server Faces – web framework (built from JSP)
Business/Service Tier Technologies:
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Enterprise Java Bean EJB – business components
JTA – transaction API
Persistence Tier Technologies:
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JDBC – lowest level database programming
Java Persistence API JPA – Object Relational Mapping framework
Integration Technologies:
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Java Connector Architecture JCA – API to access legacy systems (like SAP)
Java Messaging Service JMX – send JMS messages (like MQ)
Web Services JAX-WS, JAX-B, JAX-R – web service stack support
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J2EE Platform from post .COM era (2002-2004)
Client (mostly browser based)
Utilities and Core Services
Logging (Wrapper)
Tracing (Wrapper)
Exception Framework
Base Classes/Frameworks
Alert (like HP Open View)
Cache (Wrapper)
Static Data
Security/SSO
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Web Application
Application Server
Governance
Standards, Best Practices/Guidelines
Architecture Review Boards etc.
Struts 1.x (MVC)
JSTL (Tag Library)
MyFaces/Sun JSF RI
Apache Commons (Utility)
Apache Log4j (Logging)
Hibernate(Persistence)
iBatis (Persistence)
iText (PDF)
POE (MS Docs)
Quartz (Timer Service)
Castor (XML Framework)
Apache Xerces/Xalan (XML)
Apache Axis (Web Services)
SSO
OSCache/EHCache (Cache)
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EJB
Web
Session
Entity
MDB
JSP
Servlet
JCA
JTA
Mail
JMS
JAAS
JMX
JAXB
Integration/Middleware
Business Rule Engine
ETL
Messaging/MQ
FTP
Web Services
Proprietary Scripts etc.
Screen Scraping
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J2SE 1.3 – 1.4
JNI
RMI
JNDI
JDBC
JavaBean
Java 3D
Java 2D
Swing
AWT
MVC
DAO
Command
Factory
Business Delegate
Business Façade
Decorator
Value Object
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Open Source
J2EE 1.3 – 1.4
JAX-R
Design
Patterns
Containers and Services for UI, Business, Database
Security
Administration and Deployment
Value Add Services (Proprietary Frameworks etc.)
JAX-RPC
SDLC and Development Tools
XP, Scrum, RUP, Waterfall
Eclipse, IBM WSAD/RAD, NetBeans, JBuilder, IntelliJ
Code Analyzers (Checkstyle, FindBugs), Unit Test Frameworks (JUnit, TestNG)
UI: HTML, CSS/DHTML, JavaScript, AJAX, Applets, Flash
Application Logic, Business Logic, Data Access Logic
Enterprise Application Integration (EAI)
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J2EE Platform Observations from 2002-2004
Leveraged lots of open source libraries to fill in the J2EE specification gaps (like Web MVC
Framework, XML, Web Services). Soon there would be competing and redundant technologies such
as XML, Web Services, Logging, etc.. The Enterprise and Application Architect definitely had their
work cut out for them. What technologies do we use?
Some J2EE specifications were of little value to the enterprise (for example, Entity Beans (CMP or
BMP) and Stateful EJB’s…..J2EE 1.2 only supported remote Session Beans!).
Enterprise Integration was tightly coupled and reuse of enterprise assets not fully thought out or
realized.
Application Servers often provided proprietary (and competing) technologies and frameworks
(Portlets, Web, Security, etc.).
Lots of programming models to learn.
Governance was often over looked causing lots of inconsistencies in architecture and duplication of
code/frameworks.
Most development methodologies were still very “water fall”. XP was just taking off.
Development Tools needed improving.
Generally there was very high TCO for 1st generation (MVC-1) and 2nd generation (MVC-2)
applications.
De-facto Standard Application Servers: WebLogic, WebSphere, and some Oracle.
Increasing frustration with J2EE standard (some of it was justified and some was not).
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J2EE Web 1.5/2.0 Application Architecture (2005-present)
Client (not just browser based anymore)
Web Application
Struts2 Framework
Open Source
Struts2 (MVC)
Apache Commons (Utility)
iBatis (Persistence)
iText (PDF)
POE (MS Docs)
Quartz (Timer Service)
Apache Axis (Web Services)
OSCache/EHCache (Cache)
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Rails/Grails Framework
GWT Framework
Utilities and Core
Services
Logging/Tracing (Wrapper)
Exception Framework
Base Classes/Frameworks
Alert (like HP Open View)
Cache (Wrapper)
Static Data
Security/SSO
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Object Model
Application Domain Model
Business Rule Engine
Presentation
HTML, CSS, JavaScript, AJAX
JSF, SpringMVC, JSP, Servlets, JSTL
Facelets, Seam, Spring WebFlow
Business
POJO (via Spring or Session)
Message Driven Beans
Timer Beans
Web Services
SOA
EAI
ESB, BPM
WS-*
UDDI
WSDL
XML
JCA
ETL
JMS/MQ
Data Access
JDBC, SQL, SP
JPA/Hibernate/TopLink/iBatis
OLTP DB
J2EE Application Server (now some open source)
EE 5
J2SE 5
Spring
DI
AOP
SpringMVC
WebFlow
Security
Open JDK
Java, Ruby, Groovy, Python, Scala
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Legacy Systems
And
Legacy DB
Or DW
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Observations from 2005-2007
Move away from Struts 1.x or proprietary frameworks to newer web frameworks like JSF (plus
Facelets, Seam, and Ajax4Jsf) or Struts2 or SpringMVC (with WebFlow).
Move toward annotation based configuration (versus mass of XML configuration files).
Less Open Source required (due to maturity of EE specification, Spring, and open source application
servers like JBoss, Glassfish, Tomcat 5/6). Apache Foundation, Spring, Craig McClanahan (JSF),
Rod Johnson(String/EJB3), Gavin King(Hibernate/JPA) were really influencing and pushing the
Java/J2EE platform forward.
Spring Framework getting lots of traction in the industry (dependency injection (simple but
powerful!), POJO based for simpler programming model, AOP (for security, transactions, tracing,
etc), wrappers for integration with EJB, WS, etc.).
NetBeans IDE is becoming a viable and powerful IDE (Eclipse finally has some competition). Eclipse
Foundation followed suite and also released Eclipse Europa. No need to buy a J2EE IDE now.
Rather then reinvent we must reuse in the Enterprise, move from vertical applications to Enterprise
wide applications => SOA and leverage full Web Service stack, ESB, BPM.
New EE web applications can be built much quicker and with much less code. My last project, using
JSF and Spring and iBatis, was built with 50% less code, delivered on time (actually over delivered
by adding more features requested from our customer), and was 25% under budget.
Google influence => Google Web Toolkit, Google Docs, Google Maps, etc.
Sun and Microsoft finally working together (WS-* in 2006) => that is a good thing for everybody!
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Course #4
Example Java EE Programming
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Course Objectives
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Learn about the layers of a Java EE application.
> Learn a few common/popular design patterns.
> Walk through a “Hello World” web application.
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The Layers of a Java EE Application
Java EE Application Layers
Desktop browser, mobile
phone, STB, TV
Browser
Creates views for
presentation, handling form
data, and navigation
JSP or Web framework
such as JSF, Struts, or
SpringMVC with HTML,
CSS, and JavaScript
Business Layer
Implements business
services and enterprise
integration services
EJB, Web Services,
Message Driven Beans,
Timer Beans, SpringBeans
Persistence Layer
Implements data persistence
services
JPA, Hibernate, iBatis,
SQL, JDBC
Client Layer
Presentation Layer
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The Presentation Layer
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Designed using a very popular MVC design pattern
used to build Presentation Layer.
Implemented by all major web frameworks.
Helps to enforce separation of concerns so you don’t
mix presentation logic, business logic, and persistence
logic together.
Used to render HTML (generally) to a browser.
Model View Controller
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Model: data from business services to display
• View: views or web pages
• Controller: handles page events and navigation between
pages
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The MVC Design Pattern Diagram 1
Browser
Request
Response
Controller
Forward
JSP (View)
JavaBean
(Model)
Application Server
Services
Enterprise Servers and Data Sources
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The MVC Design Pattern Diagram 2
Browser
Request (POST)
Include JS, CSS
Response
Include Page Fragments
Event Handler
System
Exception
Forward
Controller
xhtml
xhtml
JSP (View)
Error JSP
To Error JSP
(from System
Exception)
Application
Exception
Request
or
Session
JavaBean
(Model)
Include Tab Libs
Data binding
with tag
lbrary
Delegate
Business Tier
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The Business Layer
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Driven by your business use cases defined by your
business requirements.
Implements your business services.
Should be designed using interfaces (design by
contract).
Can be a façade to other enterprise services deployed
on an ESB or other SOA infrastructure.
Acts as façade to persistence layer or enterprise data
services.
Supports other responsibilities:
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Transaction Management (using a service container)
Security (using a service container)
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The Business Layer Diagram 1
Client
Application
Exception
TO
System
Exception
Interface
Business Delegate
Begin Tx
Implemtation
Factory
Business Service 1
Facade
Business
Rules
TO
Interface
Interface
Interface
Interface
DAO 1
DAO 2
DAO 3
Service 2
Transaction Mgr
Transaction Boundary
TO
End Tx
Config
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The Business Layer Diagram 2
Client
Begin Tx
Interface + Implemtation
Business Service 1
Facade
Business
Rules
Config
or
Annotations
TO
Interface
Interface
Interface
Interface
DAO 1
DAO 2
DAO 3
Service 2
Transaction Mgr
Dependency
Injection:
DAO1, DAO2,
DAO3, and
Service 1 and 2
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System
Exception
Transaction Boundary
Application
Exception
End Tx
Config
or
Annotations
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The Persistence Layer
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Designed using the CRUD design pattern.
Is simply responsible for persistence of your entity or
domain object model.
Should not be aware of transaction boundaries.
Supported today by modern Object Relational Mapping
(ORM) frameworks such as JPA, Hibernate, and iBatis.
C R U D operations:
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Create: add or insert operation
• Read: read operation
• Update: update operation
• Delete: delete operation
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“Hello World” Java EE Web Application
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Can you really build a working N-Tier Hello World web
application in less then 10 classes?
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Let’s go build a simple web application ………
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“Hello World” Application
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2 UI Events:
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Button click handler for the ‘Test Me’ button
Button click handler for the ‘Save Me’ button
2 Business Use Cases:
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Validate the Model
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Business Rule: If Name is ‘Mark’ then Model can be persisted
Save the Model
Model:
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Simple JavaBean that just has a Name attribute
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“Hello World” Web Tier Implementation
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View => JSF Page
> Controller => JSF Event Handler class
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The 2 UI Events are implemented in a JSF Event Handler
class
Business service is injected into this class
The Model => clean separation between Web
Application Model and the Domain Model, so we don’t
mix UI data with our Business data
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“Hello World” Business Tier Implementation
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Uses Stateless EJB 3.0 JavaBeans.
> Uses Container Managed Transactions
> DAO is injected into this class
> Implements our 2 business use cases
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Can be designed using Noun’s and Verbs discovered when
you write your use case.
Validate the Model
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Validate is the verb and the Noun is Model => validate(Model)
Save the Model
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Save is the verb and the Noun is Model => save(Model)
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“Hello World” Data Access Tier Implementation
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Implements standard CRUD operations via an Interface
Uses Stateless EJB 3.0 JavaBeans (DI issue with EE5).
Forces Transactions to be declared external to DAO
JPA support is injected into this class
Implements our single Update CRUD use case
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“Hello World” Conclusion
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A simple Java EE 5 web application was written using 3
implementation classes, 2 interfaces, 2 model classes, 1
Controller class, and 1 JSF page.
> This demo application made use of EE 5 dependency
injection and container managed transactions, which
virtually eliminated the need to implement any
infrastructure classes (and lots of old design patterns).
> This demo application could have been enhanced by
using more elaborate use of Base Classes, which you
develop as part of a standard corporate Application
Framework.
> It really is that easy (if you are using modern technology)!
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Where Can I Learn More?
Go to the Java TCC site to links for lots of good industry
references.
Go read the AAA-NCNU Java Standards.
Go read the AAA-NCNU Java Best Practices.
Get my Java EE Application Design Template.
Get the Java Reference Implementation.
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Appendix
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References
Anonymous. 2009. Wikipedia. Retrieved April 10, 2009
from http://www.wikipedia.com
Sun Java Tutorials, Retrieved May 14, 2009
from http://java.sun.com/docs/books/tutorial/java/concepts/index.html
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