Book Image

Hands-On Design Patterns with Delphi

By : Primož Gabrijelčič
Book Image

Hands-On Design Patterns with Delphi

By: Primož Gabrijelčič

Overview of this book

Design patterns have proven to be the go-to solution for many common programming scenarios. This book focuses on design patterns applied to the Delphi language. The book will provide you with insights into the language and its capabilities of a runtime library. You'll start by exploring a variety of design patterns and understanding them through real-world examples. This will entail a short explanation of the concept of design patterns and the original set of the 'Gang of Four' patterns, which will help you in structuring your designs efficiently. Next, you'll cover the most important 'anti-patterns' (essentially bad software development practices) to aid you in steering clear of problems during programming. You'll then learn about the eight most important patterns for each creational, structural, and behavioral type. After this, you'll be introduced to the concept of 'concurrency' patterns, which are design patterns specifically related to multithreading and parallel computation. These will enable you to develop and improve an interface between items and harmonize shared memories within threads. Toward the concluding chapters, you'll explore design patterns specific to program design and other categories of patterns that do not fall under the 'design' umbrella. By the end of this book, you'll be able to address common design problems encountered while developing applications and feel confident while building scalable projects.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
About Packt

Abstract factory

The abstract factory pattern is closely related to the factory method pattern. Sometimes, the problem requires the creation of multiple distinct objects that are somehow related. In such a case, we could introduce multiple factory methods, but then we have to manage them separately, which increases the possibility of implementations becoming out of sync. This approach also makes it hard to share common logic and state between those factory methods. A better way is to introduce an abstract factory, which functions as a factory for factories.


If a factory method is a kid with a cookie cutter, an abstract factory is a kitchen chef. Give them a set of cooking tools and they'll make you a great dish. Give them access to a baking set and they'll make you a perfect pie.

We can implement abstract factory in the same object-oriented way that was used in the factory method pattern. We have to create a base abstract factory class that defines factory methods and a base class for...