Book Image

Scala Design Patterns

By : Ivan Nikolov
Book Image

Scala Design Patterns

By: Ivan Nikolov

Overview of this book

Scala has become increasingly popular in many different IT sectors. The language is exceptionally feature-rich which helps developers write less code and get faster results. Design patterns make developer’s lives easier by helping them write great software that is easy to maintain, runs efficiently and is valuable to the company or people concerned. You will learn about the various features of Scala and be able to apply well-known, industry-proven design patterns in your work. The book starts off by focusing on some of the most interesting features of Scala while using practical real-world examples. We will also cover the popular "Gang of Four" design patterns and show you how to incorporate functional patterns effectively. By the end of this book, you will have enough knowledge and understanding to quickly assess problems and come up with elegant solutions.
Table of Contents (20 chapters)
Scala Design Patterns
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Index

The abstract factory


The abstract factory is another design pattern from the family of factory patterns. The purpose is the same as all factory design patterns—to encapsulate the object creation logic and hide it from the user. The difference is how it is implemented.

The abstract factory design pattern relies on object composition in contrast to inheritance, which is used by the factory method. Here we have a separate object, which provides an interface to create instances of the classes we need.

Class diagram

Let's keep using the preceding SimpleConnection example here. The following diagram shows how the abstract factory is structured:

As we can see from the preceding figure, now we have a hierarchy of factories rather than a method inside our database client. We will be using the abstract DatabaseConnectorFactory in our application and it will be returning the right objects, depending on the actual instance type.

Code example

Let's have a look at our example from the source point of view....