Andreas Martin - Page 1

Master of Science in Business Information Systems FHNW Pre-Master Information Systems

1. Java Enterprise Edition and Information Systems Layering

Andreas Martin

1. Java Enterprise Edition and Information Systems Layering

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What is Java EE?

«Java EE 7 is an umbrella specification»

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Source: The Java EE 7 Tutorial, Oracle Corporation, 2013: http://docs.oracle.com/javaee/7/tutorial/doc/javaeetutorial7.pdf 1. Java Enterprise Edition and Information Systems Layering

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Prejudice against Java EE

1. Java Enterprise Edition and Information Systems Layering

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1. Complexity

Java EE is

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2. Performance

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3. Stability

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…to much coffee… Enterprise JavaBeans

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Java EE 7 We love it…

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Fundamental Principle: Layering

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What is the difference between “Layer” and “Tier”?

«Layers are a way of organizing your code.»

«Tiers are about where your code runs.»

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The Latte Macchiato «Layering» Principle

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Presentation Layer

Goal: Display of information, processing / forwarding of user interactions. Technologies: JavaServer Faces (JSF), JavaServer Pages (JSP), Servlets, etc.

Business (Logic) Layer

Goal: Reproduction of actions or «verbs» of the application (buy a book, print an order, deliver a book, etc.). Technologies: Enterprise Java Beans (EJBs)

Persistence Layer

Goal: Reproduction of database attributes, information or «nouns» in object / class attributes (Object-Relational Mapping, ORM). Technologies: Java Persistence API (JPA)

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Java EE Layering

1. Java Enterprise Edition and Information Systems Layering

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Java EE and (Technical) Tiers

1. Java Enterprise Edition and Information Systems Layering

Source: The Java EE 7 Tutorial, Oracle Corporation, 2013: http://docs.oracle.com/javaee/7/tutorial/doc/javaeetutorial7.pdf

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Java EE 7 – Typical Layering

1. Java Enterprise Edition and Information Systems Layering

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Business Layer

Java EE 7 – Typical Layering including Process Layer

1. Java Enterprise Edition and Information Systems Layering

Databases

Persistence Layer

@EntityManager (JPA)

(JPA) @Entity (JPA)

Session Bean (EJB)

@PersistenceContext

Serv

ice

Laye

r

Pre

sen

tati

on

La

yer

Users Service Consumer

Process Layer

User Interface Component

Service Interface

Business Process

@EJB / @Inject

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Business Layer

Java EE 7 – Typical Layering

1. Java Enterprise Edition and Information Systems Layering

Persistence Layer

@EntityManager (JPA)

(JPA) @Entity (JPA)

Session Bean (EJB)

@PersistenceContext

Presentation Layer

Facelets (JSF) @ManagedBean (JSF)

Facelets (JSF)

Users

Databases

@EJB / @Inject

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Package Structure Recommendation …

1. Java Enterprise Edition and Information Systems Layering

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Package Structure

Recommendation - (ch.xx.project…):

.domain (Persistence Layer): Entity classes

.dao (Business Layer in Java EE and Persistence / Data Access Layer in Spring): DAO- classes (Java EE 7: Abstract Facade / Spring: Abstract Facade and Specific DAO)

.business (Business Layer): Enterprise Java Beans

.service (Service Layer): Service Facade, SOAP und REST Web- Services

.controller (Presentation Layer): Controller classes

.view (Presentation Layer): Views

.dto (Layer independent) : Transfer objects

.util (Layer independent) : Utility classes

6. Java EE 6 Architecture