Book Image

Hands-On Design Patterns with Java

By : Dr. Edward Lavieri
2 (1)
Book Image

Hands-On Design Patterns with Java

2 (1)
By: Dr. Edward Lavieri

Overview of this book

Java design patterns are reusable and proven solutions to software design problems. This book covers over 60 battle-tested design patterns used by developers to create functional, reusable, and flexible software. Hands-On Design Patterns with Java starts with an introduction to the Unified Modeling Language (UML), and delves into class and object diagrams with the help of detailed examples. You'll study concepts and approaches to object-oriented programming (OOP) and OOP design patterns to build robust applications. As you advance, you'll explore the categories of GOF design patterns, such as behavioral, creational, and structural, that help you improve code readability and enable large-scale reuse of software. You’ll also discover how to work effectively with microservices and serverless architectures by using cloud design patterns, each of which is thoroughly explained and accompanied by real-world programming solutions. By the end of the book, you’ll be able to speed up your software development process using the right design patterns, and you’ll be comfortable working on scalable and maintainable projects of any size.
Table of Contents (15 chapters)
Free Chapter
Section 1: Introducing Design Patterns
Section 2: Original Design Patterns
Section 3: New Design Patterns

Understanding the circuit-breaker design pattern

The circuit-breaker design pattern is based on the same concept as an electrical circuit. As you can see in the following diagram, when the circuit is open, the flow of electricity is impeded and cannot flow between the two pointsthe power source and light bulb in our example. When the circuit is closed, electricity is unimpeded and the light bulb can receive power:

Circuit breakerlight-switch example

The circuit-breaker design pattern is modeled after electrical circuits. This design pattern has three possible states:

  • Open: If the state is open, then an error will be returned.
  • Closed: This is the preferred state where functionality is permitted.
  • Half-Open: This state is used after an open state error and a wait period. The function will allow one use as a test.

If the test is successful, the circuit will be closed...