Book Image

Design Patterns and Best Practices in Java

By : Kamalmeet Singh, Adrian Ianculescu, Lucian-Paul Torje
Book Image

Design Patterns and Best Practices in Java

By: Kamalmeet Singh, Adrian Ianculescu, Lucian-Paul Torje

Overview of this book

Having a knowledge of design patterns enables you, as a developer, to improve your code base, promote code reuse, and make the architecture more robust. As languages evolve, new features take time to fully understand before they are adopted en masse. The mission of this book is to ease the adoption of the latest trends and provide good practices for programmers. We focus on showing you the practical aspects of smarter coding in Java. We'll start off by going over object-oriented (OOP) and functional programming (FP) paradigms, moving on to describe the most frequently used design patterns in their classical format and explain how Java’s functional programming features are changing them. You will learn to enhance implementations by mixing OOP and FP, and finally get to know about the reactive programming model, where FP and OOP are used in conjunction with a view to writing better code. Gradually, the book will show you the latest trends in architecture, moving from MVC to microservices and serverless architecture. We will finish off by highlighting the new Java features and best practices. By the end of the book, you will be able to efficiently address common problems faced while developing applications and be comfortable working on scalable and maintainable projects of any size.
Table of Contents (15 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Filtering Observables


These are the operators that selectively emit items from a given Observable based on a given condition/constraint.

The debounce operator

Emitting only after a specific timespan has passed can be done using these methods:

  • debounce: Mirrors the initial Observable, except that it drops items emitted by the source that are followed by another item within a period of time
  • throttleWithTimeout: Emits only those items that are not followed by another emitted item within a specified time window

In the following example, we'll drop items that are fired before our debounce timespan of 100 ms has passed; in our case it is just the last value managed. Again, by using the test scheduler, we advance the time:

The distinct operator

This removes distinct items emitted by an Observable using the following methods:

  • distinct: Emits only distinct elements
  • distinctUntilChanged: Emits only elements that are distinct from their immediate predecessors

In the following code, we will see how to use the...