Book Image

Hands-On Design Patterns with C++ (Second Edition) - Second Edition

By : Fedor G. Pikus
5 (1)
Book Image

Hands-On Design Patterns with C++ (Second Edition) - Second Edition

5 (1)
By: Fedor G. Pikus

Overview of this book

C++ is a general-purpose programming language designed for efficiency, performance, and flexibility. Design patterns are commonly accepted solutions to well-recognized design problems. In essence, they are a library of reusable components, only for software architecture, and not for a concrete implementation. This book helps you focus on the design patterns that naturally adapt to your needs, and on the patterns that uniquely benefit from the features of C++. Armed with the knowledge of these patterns, you’ll spend less time searching for solutions to common problems and tackle challenges with the solutions developed from experience. You’ll also explore that design patterns are a concise and efficient way to communicate, as patterns are a familiar and recognizable solution to a specific problem and can convey a considerable amount of information with a single line of code. By the end of this book, you’ll have a deep understanding of how to use design patterns to write maintainable, robust, and reusable software.
Table of Contents (26 chapters)
1
Part 1: Getting Started with C++ Features and Concepts
5
Part 2: Common C++ Idioms
10
Part 3: C++ Design Patterns
18
Part 4: Advanced C++ Design Patterns

Drawbacks of the Non-Virtual Interface

There aren’t many drawbacks regarding the use of the NVI. That is why the guideline to always make virtual functions private, and use the NVI to call them, is widely accepted. However, there are some considerations that you must be aware of when deciding whether the Template Method is the right design pattern to follow. The use of the template pattern may lead to fragile hierarchies. Also, there is some overlap between design problems that can be solved using the template pattern and the ones better served by the strategy pattern, or, in C++, policies. We will review both considerations in this section.

Composability

Consider the earlier design for LoggingFileWriter. Now, suppose that we want to also have CountingFileWriter that counts how many characters were written into the file:

class CountingFileWriter : public FileWriter {
  size_t count_ = 0;
  void Preamble(const char* data) {
    ...