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- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Developing powerful web applications with clean, manageable code makes the maintenance process much easier. Aspect-Oriented Programming (AOP) is the easiest and quickest way to achieve such results. Spring is the only Java framework to offer AOP features. The combined power of Spring and AOP gives a powerful and flexible platform to develop and maintain feature-rich web applications quickly.
This book will help you to write clean, manageable code for your Java applications quickly, utilizing the combined power of Spring and AOP. You will master the concepts of AOP by developing several real-life AOP-based applications with the Spring Framework, implementing the basic components of Spring AOP: Advice, Joinpoint, Pointcut, and Advisor.
This book will teach you everything you need to know to use AOP with Spring. It starts by explaining the AOP features of Spring and then moves ahead with configuring Spring AOP and using its core classes, with lot of examples. It moves on to explain the AspectJ support in Spring. Then you will develop a three-layered example web application designed with Domain-Driven Design (DDD) and built with Test-Driven Development methodology using the full potential of AOP for security, concurrency, caching, and transactions.
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Seitenzahl: 204
Veröffentlichungsjahr: 2009
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Table of Contents
Spring 2.5 Aspect-Oriented Programming
Massimiliano Dessì
Spring 2.5 Aspect-Oriented Programming
Copyright © 2009 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, Packt Publishing, nor its dealers or distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: February 2009
Production Reference: 1170209
Published by Packt Publishing Ltd.
32 Lincoln Road
Olton
Birmingham, B27 6PA, UK.
ISBN 978-1-847194-02-2
www.packtpub.com
Cover Image by Parag Kadam (<[email protected]> )
Credits
Author
Massimiliano Dessì
Reviewer
Stefano Sanna
Acquisition Editor
Rashmi Phadnis
Development Editor
Dhiraj Chandiramani
Technical Editor
Abhinav Prasoon
Copy Editor
Sneha Kulkarni
Editorial Team Leader
Akshara Aware
Project Manager
Abhijeet Deobhakta
Project Coordinator
Neelkanth Mehta
Indexer
Rekha Nair
Proofreader
Chris Smith
Production Coordinator
Aparna Bhagat
Cover Designer
Aparna Bhagat
About the Author
Massimiliano Dessì is an experienced Java developer who started developing JEE applications in 2000. In 2004 he discovered the Spring Framework 1.0, and since then he has been one of its most enthusiastic users.
Massimiliano is specialized in design and development of enterprise Web-based applications, such as portals, content management systems and banking applications. JEE technology and applied agile methodologies like eXtreme Programming are his core skills. He currently works as a Software Architect and Engineer for Sourcesense (www.sourcesense.com), one of the leading European Open Source System Integrators. He have a strong background as a community supporter and open-source software contributor. He's also an active technical writer, author of various articles, publications, and reviews availables on http://www.jugsardegna.org/vqwiki/jsp/Wiki?MassimilianoDessi and on http://wiki.java.net/bin/view/People/MassimilianoDessi.
Massimiliano also speaks regurarly at Users Groups conferences (including Java Users Groups, Spring Framework User Group, Javaday, and Linux Users Groups).
He is one of the founders of Java User Group Sardinia (http://www.jugsardegna.org), as well as the founder of "Spring Framework Italian User Group", "Jetspeed Italian user Group" and "Groovy Italian User Group".
He maintains a personal weblog at: http://jroller.com/page/desmax.
Massimiliano lives in Cagliari, Sardinia with his family.
About the Reviewer
Stefano Sanna is senior engineer and Java ME Tech Lead at Beeweeb Technologies (Rome), where his activities are focused on mobile multimedia applications (JME, iPhone, Android). His experience on Java for mobile devices began in 1999 on a Psion handheld computer. He is author of the Italian book "Java Micro Edition", targeted on developing network-oriented applications for mobile phones and published by Hoepli (Nov 2007). He has written more than 50 technical articles on Java ME, mobile technologies, and Linux. He has presented more than 30 seminars on the same topics, including Sun SPOTs and Arduino sensor networks. Stefano supports some Italian communities: JUG Sardegna, Java Mobile Developers Forum, and Java Italian Association. Before joining Beeweeb, he was a software engineer at CRS4 (Sardinia) in the Network Distributed Applications group, where he worked on multimodal applications and mobile cartography. He regularly writes about mobile computing, Java, embedded systems, and good Italian food on his blog: http://www.gerdavax.it.
This book is dedicated to my wife Monica and my children Michele, Mattia and Chiara
Preface
In software engineering, mostly low-level languages were used for many years, which were closer to the computer machine code than to human language. In the 70s, Brian Kernighan and Dennis Ritchie created the language C. It was quite similar to human language, making it easier and faster to write code, while keeping a high level of abstraction. This allowed the realization of concepts and ideas, which was not possible for the previous languages as they were forced to focus on the processor's language. Later, Smalltalk and C++ permitted the shaping of concepts and ideas through objects‚ providing a new way to structure applications and write programs. With the object-oriented languages, any system could be created with increasing complexity in a more manageable way, thanks to the modeling of entities in the form of types and the collaboration between them. In some cases, object-oriented programming introduces or causes inefficiencies, and aspect-oriented programming helps in filling these gaps. The aim of Aspect-Oriented Programming (AOP) is not to replace Object-Oriented Programming (OOP), but to complement it, allowing you to create clearer and better structured programs. Gregor Kiczales, one of the founders of AOP, said (an extract from http://www.cs.ubc.ca/~gregor/papers/kiczales-ECOOP1997-AOP.pdf)"We have found many programming problems for which neither procedural nor object-oriented programming techniques are sufficient to clearly capture some of the important design decisions the program must implement. This forces the implementation of those design decisions to be scattered throughout the code, resulting in tangled code that is excessively difficult to develop and maintain." Neither aspect-oriented programming nor object-oriented programming can make up for a bad design: The first assumption is that a software system is well-designed. There is no solution for a badly designed system, and also none for a badly implemented system. There is only one good strategy: to change it. The difference between a good and a bad design is the capacity to evolve and adapt to new requirements without being twisted. Object-oriented programming, supported by aspect-oriented programming, helps designers and developers in this direction.
What this book covers
Chapter 1 introduces the ideas that led to Aspect-Oriented Programming. An overview of main concepts of AOP is used to describe components and features provided by Spring AOP, while a set of concise yet clear examples lets the reader discover what can actually be done with AOP.
Chapter 2 describes in detail the fundamentals of AOP in Spring, presenting interfaces and classes introduced in early 1.x versions of the framework. This chapter shows how to use AOP programmatically, to let the reader discover the basis of Spring AOP and the components that implement Aspect-Oriented Programming in Spring.
Chapter 3 explains how the weaving of AOP components is done using the proxy pattern and JDK or CGLIB implementations. It describes the purpose of proxies and how to use them effectively. Some practical examples show how to use the proxies programmatically, with annotations and with XML; they explain the ProxyFactoryBean and how to make the programmer's work easier with AutoProxy. The chapter describes also some smart techniques on target sources.
Chapter 4 explains how Spring AOP is supported by AspectJ. Configuration activity is made simpler, more flexible and more powerful, thanks to annotations and the syntax of AspectJ on pointcuts (without which those costructs would not be available). All examples show how to use AspectJ with both annotations and XML. The chapter contains practical recipes for specific cases, such as the injection of dependencies on domain objects, the management of aspects' priority, the use of different life cycles for Aspects and how to use Load Time Weaving. The chapter ends with some strategies on how to choose different AOP approaches to fulfil specific requirements.
Chapter 5 describes the design alternatives that can be implemented using AOP. These alternatives are solutions for common requirements: concurrency, caching, and security. Using AOP, they can be achieved in a very elegant and easy way, being at the same time totally transparent for the system where they are applied.
Chapter 6 introduces Domain-Driven Development as a alternative way to design applications. The prototype example presented in this chapter is a typical Three-Layer application, where DDD is used for design and AOP is used to inject the dependencies on domain objects. iBatis is used for persistence to the database.
Chapter 7 completes the prototype application started in Chapter 6, showing the application layer and the user interface. The latter is implemented with Spring MVC using annotations. Integration and unit tests are used to verify the correctness of the classes; DBUnit is used to test persistence classes, while some Mock classes are used to test the UI. The chapter contains the configurations for the prototype infrastructure, including autentication and authorization with Spring Security and the JUnit 4.5 test suite.
Chapter 8 describes the development tools needed to include Spring AOP and AspectJ in the Eclipse IDE. The reader can find here detailed istructions on how to configure Eclipse with the plug-ins for Spring and for the AspectJ Development Tool, and how to install the PostgreSQL database and the Apache Tomcat servlet engine. All installation procedures are described for the three main operating systems: Ubuntu Linux, Apple Mac OS X, and Microsoft Windows XP.
What you need for this book
The book requires a basic knowledge of Spring and it's configuration. It needs software like Java Development Kit (JDK) 1.5 or higher, Spring 2.5.6 (at the time of writing on this book), Eclipse (3.4.1 or higher version), Eclipse plug-ins, Tomcat Apache (Tomcat 6.x), and PostgreSQL (version 8.3).
Who this book is for
This book is written for software architects, engineers, and developers that want be able to write applications in a more modular and concise way, without learning AspectJ or using languages other than Java and frameworks other than Spring.
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