Book Image

Practical Design Patterns for Java Developers

By : Miroslav Wengner
Book Image

Practical Design Patterns for Java Developers

By: Miroslav Wengner

Overview of this book

Design patterns are proven solutions to standard problems in software design and development, allowing you to create reusable, flexible, and maintainable code. This book enables you to upskill by understanding popular patterns to evolve into a proficient software developer. You’ll start by exploring the Java platform to understand and implement design patterns. Then, using various examples, you’ll create different types of vehicles or their parts to enable clarity in design pattern thinking, along with developing new vehicle instances using dedicated design patterns to make the process consistent. As you progress, you’ll find out how to extend vehicle functionalities and keep the code base structure and behavior clean and shiny. Concurrency plays an important role in application design, and you'll learn how to employ a such design patterns with the visualization of thread interaction. The concluding chapters will help you identify and understand anti-pattern utilization in the early stages of development to address refactoring smoothly. The book covers the use of Java 17+ features such as pattern matching, switch cases, and instances of enhancements to enable productivity. By the end of this book, you’ll have gained practical knowledge of design patterns in Java and be able to apply them to address common design problems.
Table of Contents (14 chapters)
1
Part 1: Design Patterns and Java Platform Functionalities
4
Part 2: Implementing Standard Design Patterns Using Java Programming
8
Part 3: Other Essential Patterns and Anti-Patterns

Decoupling a method execution with an active object pattern

The active object design pattern separates and defers method execution from method invocation by running its own control thread.

Motivation

The active object pattern introduces a transparently concurrent model to the application. It creates and starts an internal thread that executes the required logical, critical section. An active object instance exposes a public interface that a client can use to run an encapsulated critical section. An external, client-initiated event is queued and ready to execute. The execution step is performed by the internal scheduler. The result can be passed to the appropriate handler in a callback style.

Sample code

Let us introduce an example of a moving vehicle with a radio system (Example 6.1):

public static void main(String[] args) throws Exception {
    System.out.println("Active Object Pattern, moving
        ...