Book Image

Delphi High Performance - Second Edition

By : Primož Gabrijelčič
5 (1)
Book Image

Delphi High Performance - Second Edition

5 (1)
By: Primož Gabrijelčič

Overview of this book

Performance matters! Users hate to use programs that are not responsive to interactions or run too slow to be useful. While becoming a programmer is simple enough, you require dedication and hard work to achieve an advanced level of programming proficiency where you know how to write fast code. This book begins by helping you explore algorithms and algorithmic complexity and continues by describing tools that can help you find slow parts of your code. Subsequent chapters will provide you with practical ideas about optimizing code by doing less work or doing it in a smarter way. The book also teaches you how to use optimized data structures from the Spring4D library, along with exploring data structures that are not part of the standard Delphi runtime library. The second part of the book talks about parallel programming. You’ll learn about the problems that only occur in multithreaded code and explore various approaches to fixing them effectively. The concluding chapters provide instructions on writing parallel code in different ways – by using basic threading support or focusing on advanced concepts such as tasks and parallel patterns. By the end of this book, you’ll have learned to look at your programs from a totally different perspective and will be equipped to effortlessly make your code faster than it is now.
Table of Contents (15 chapters)

Future

A significant category of operations that we would like to execute in a background thread can be summarized with the words “do something and return a result.” These operations are represented by a pattern called Future.

A Future always wraps some function. In Delphi’s Parallel Programming Library, a Future is represented by an IFuture<T> interface, where T is the data type returned by the function. This interface is created by calling the TTask.Future<T> function. IFuture<T> is derived from ITask, so it supports all ITask methods and properties, such as Status, Cancel, Wait, and so on.

The ParallelFuture demo shows two ways of using IFuture<T>. In the first scenario, the code creates a Future, does some other work, and then asks the Future about the result of the calculation. If the background calculation is not yet finished, the code waits until the result is ready. That could block the user interface, so this approach should...