Language
Country/Area
No result found
Mysterious design patterns: Why are they causing such a stir in the software engineering world?
In the world of software engineering, "design pattern" is undoubtedly a key concept. In 1994, four authors - Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides - co-authored the book Design Patterns: Elements of Reusable Object-Oriented Software for the first time to systematically elaborate on this. A concept and provides developers with 23 classic design patterns. This book not only attracted widespread attention in the software development community, but also changed the way we think about writing reusable and extensible code.
"Programming should be based on interfaces, not specific implementations."
The history and development of design patterns
The origins of design patterns can be traced back to the OOPSLA conference in 1990, where Gamma and Helm first met and discovered their common interest in creating an architecture manual. In the following years, they were joined by Johnson and Vlissides, and together they published the book in 1994. The book's influence transcends language boundaries and has sold more than 500,000 copies worldwide and been translated into 13 languages.
Core concepts of design patterns
In this book, the first chapter explores the basic techniques of object-oriented design. The author proposes a number of principles to promote good design, such as:
"Pursue object composition rather than class inheritance."
This principle emphasizes the use of interfaces, so that the client only needs to focus on the interface rather than the specific implementation, thereby giving full play to the dynamic binding and polymorphism of object-oriented programming.
Types of design patterns
Based on functionality, design patterns can be divided into three types: creative, structural and behavioral. Each type has its specific application scenarios and value.
Creative mode
These modes are mainly responsible for the creation of objects without directly instantiating the objects. For example, the builder pattern can simplify the creation process by separating the construction and presentation of complex objects.
"The singleton pattern allows only one instance of a class to be created."
Structural pattern
Structural patterns focus on the combination of classes and objects, using inheritance to combine interfaces and define objects to obtain new functionality. For example, the Adapter pattern promotes flexibility by allowing classes with incompatible interfaces to work together.
Behavioral Pattern
Behavioral patterns mainly explore the communication methods between objects. For example, the observer pattern allows multiple observers to respond to an event and implements an event publish/subscribe mechanism.
Reactions and criticisms of design patterns
Since its publication, the book has received widespread acclaim. In 2005, ACM SIGPLAN awarded the author the Programming Language Achievement Award for that year in recognition of his influence in programming practice and language design. However, design patterns have also caused a lot of controversy.
"When I see patterns in the program, I think it's a sign of a problem."
Some critics believe that design patterns are just an emergency solution to fill in the missing features of the C++ language, and are even described as "human compilers". Additionally, using a more static language such as Lisp, many design patterns can be simplified or eliminated, showing the significant impact of language features.
Final Thoughts
As software development environments and technologies continue to evolve, design patterns remain important knowledge that developers must master. However, do the solutions provided by design patterns still meet the needs of modern development? When using design patterns, how should developers judge their applicability and potential risks?
