Applied Java Patterns

A hands-on guide to design patterns for Java platform developers.

• Pattern-based solutions for every stage of the development lifecycle
• Documents 30 patterns, including the 23 core patterns for the Sun Certified Enterprise Architect exam
• Describes pattern use within the Java APIs—including patterns for reflection, security, AWT/Swing, RMI, JDBC, J2EE, and more

Increasingly, developers are recognizing the value of design patterns in helping to create more robust, scalable, reliable, and maintainable applications. Now there's a book that can help you bring the power of patterns to your Java-based projects.

Sun Microsystems experts Steve Stelting and Olav Maassen bring together today's best pattern-based techniques and demonstrate pattern use for a variety of business systems. This practical guide features proven techniques for all types of patterns, from system architecture to single classes

After briefly reviewing the fundamentals of design patterns, the authors describe how these patterns can be applied effectively to the Java platform. Next, they provide a pattern catalog, organized into four major categories—the creational, behavioral, structural, and system patterns. In addition, they identify patterns and present techniques for pattern use in the core Java APIs as well as the APIs for distributed development.

APIs covered include:

• Event handling
• Collection API
• JDBC
• RMI
• CORBA

Applied Java Patterns also features a section on pattern use in systems built with J2EE and JINI technologies, and coverage of the servlet, JSP, EJB, and JavaSpaces APIs.

Without a doubt, this accessible and up-to-date guide can help you enhance your Java platform programming skills.

Online Sample Chapter

Creational Patterns: Creating Objects in an OO System

Preface

Preface

During the many Java programming language courses we teach, we have found that only a few programmers know what design patterns are when asked. About one in ten is able to name a few patterns off the top of his or her head. Of course, the concepts behind the patterns are familiar to many programmers. When we demonstrate patterns in the classroom, developers know and recognize them.

We decided to create a pattern catalog for the Java programming language developers who understand at a basic level why patterns are a good idea, and are interested in applying them, but want a practical, hands-on guide to just how and why to use each individual pattern. We've kept the book casual and frank in tone, and included full working Java code examples for each.

We will have succeeded when you complete this book having not only learned about design patterns and the Java programming language, but having had fun reading it, as well.

This book will teach you the essential design patterns and how you can use them in your Java application. Furthermore, this book will show you where patterns are used in Java technology APIs and why they were used.

This book is intended for experienced Java programmers who want to build better applications. You should be comfortable with the Java programming language and be familiar with most of the basic Java APIs. Some knowledge of UML is useful, but not required. We recommend UML Distilled by Martin Fowler as a UML reference.

This book is divided into two parts. Part I, "Commonly Used Patterns," is organized like a pattern catalogue, reference-style.

Chapter 1: "Creational Patterns" on page 3 discusses patterns that create objects: Abstract Factory, Builder, Factory Method, Prototype, and Singleton.

Chapter 2: "Behavioral Patterns" on page 39 is focussed on the patterns that can determine the behavior of your object model: Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, and Visitor.

Chapter 3: "Structural Patterns" on page 139 describes patterns that can bring structure to your application and has the following patterns: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, HOPP, and Proxy.

Chapter 4: "System Patterns" on page 205 describes the patterns that help you build better architectures: Callback, Router, MVC, Session, Successive Update, Transaction, and Worker Thread.

Part II, "Patterns in the Java Programming Language," presents many of the Java APIs and shows the use of patterns in those API and their benefit.

Chapter 6: "Java Core APIs" on page 279 provides an overview in the familiar core APIs like Event Handling, JavaBeansTM, AWT and Swing, Collections, Input/Output, and Reflection.

Chapter 7: "Distributed Technologies" on page 303 describes selected distributed APIs and how patterns are used: JNDI, JDBC, RMI, and CORBA.

Chapter 8: "Jini and J2EE Architectures" on page 317 focuses on the two complementary frameworks Jini and J2EE. J2EE is further divided into Servlets, JSP and EJB technologies.

There are several ways to read this book. You could start at page one and read from cover to cover. However, we recommend you start with some of the easier patterns: Factory Method, Singleton, Observer, and Composite. Work your way through the book using those as starting points for your exploration. Alternatively, you might want to turn to sections in Part II first. Find an API you are familiar with and start looking for patterns there.

You can read the patterns in any order you feel most comfortable with. Later, you can use this book as a reference to refresh your memory when you want to put your knowledge of patterns into practice.

This book has a companion Web site to provide you with updates and other material: it is located at http://www.phptr.com/appliedjavapatterns

Table of Contents

Preface.

COMMONLY USED PATTERNS.

II. PATTERNS IN THE JAVA PROGRAMMING LANGUAGE.