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


The big power of multithreaded programming lies in the fact that all threads can access all the memory in the program. When we create a new thread that will process some program data, we don't need any special preparations. We just create the thread and that data will be available to it.

This, however, is also the biggest weakness of multithreaded programming. If multiple threads are accessing the same data, they can easily interfere with each other. One thread can overwrite the data of another thread or it can modify the structure that another thread is using. This results in all kinds of problems, including random crashes at unexpected locations.

As an example, imagine this situation. A first thread is walking some list and processing elements with the following code:

for i := 0 to FList.Count - 1 do

FList is a global object and while this for loop is running, the second thread deletes an element from the list with FList.Delete(0).

Let's say that the FList...