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What is a design pattern? Pattern design is a solution to common software design problems. Knowing these patterns distinguishes a professional programmer from ordinary programmers. No matter what programming language you write in, knowing and using these templates in software design can help you a lot in creating software. So we recommend that you do not miss the continuation of this study in any way.

What is a pattern design?

Over time, programmers have encountered various problems in software development. Many of these problems were independent of programming languages ​​and the like. Therefore, various solutions came to solve these problems, which are the best way to solve these problems, design patterns or Design Pattern. In other words, sets of the best solutions to common problems in the software programming process are design patterns. Pattern designs are by the hands of experienced programmers to solve common problems in object-oriented programming.

tip :

Design patterns are not part of software architectures and only provide the correct way of object-oriented coding. Therefore, these patterns only enter the realm of object-oriented coding and are independent of programming languages.

History of design patterns

Design patterns were first introduced by Christopher Alexander. Christoph Alexander referred to design patterns as solutions to problems that commonly occur in the programming process. In 1994, a group called the Gang of Four, consisting of Eric Gamma, Richard Helm, Ralph Johnson, and the Wilsides Cup, categorized design patterns into applications. The Gang of Four, or GOF for short, published these patterns in a book called Design Patterns. This book divides 23 of the design patterns into three general categories and introduces and teaches them.

In this book, Gamma and his colleagues have considered a specific structure to introduce each of the design patterns. They have refused to introduce design patterns visually. Because they believed that the introduction of design patterns required a new and specific structure. Therefore, they designed the following structure in order to better present the design of the patterns.

The main components of this structure are:

• Name and classification: states the name of the template and a short description of it.
• Purpose: In this section, a brief description of the purpose of the template is provided.
• Another name: If the design pattern is by other names, they are in this section.
• Solution: This section deals with the scenario in which the design pattern is and how to use classes and objects to solve the problem.
• Application: This section describes the conditions under which the model will be.
• Structure: In this section, the main structure of design patterns using UML is.
• Classes and objects used: The responsibilities of the classes or objects used in the design template are in this section.
• How to Collaborate: How to classify objects and objects is specified in this section.
• Implementation method: In this section, the implementation steps are discussed.
• Sample Code: In this section, examples are shown in the form of programming languages.
• Practical examples: In this section, practical examples of the design pattern are mentioned.
• Relationship between design pattern and other patterns: Related sections Design pattern with other patterns are examined in this section.

Types of design patterns in software engineering

Design patterns are divided into three general categories, Creation Design Patterns, Structural Design Patterns, and Behavioral Design Patterns, according to the applications and purposes presented for that purpose.

Creating Design Patterns

Design patterns that are provided to solve problems related to creating objects in software are called creative patterns. The most common design patterns are:

• Singleton
• Factory
• Method
• Prototype
• Abstract Factory
• Builder
• Object Pool

Structural Design Patterns

Structural design patterns are a set of solutions that help programmers solve software scalability problems. These pattern designs are used to manage the relationship between classes and objects. These design patterns are:

• Adapter
• Decorator
• Facade
• Bridge
• Composite
• Flyweight
• Proxy

Behavioral Design Patterns

Behavioral design patterns are a set of coding strategies related to the interaction and communication of objects. These design patterns are:

• Chain of responsibility
• Strategy
• Iterator
• Command
• Mediator
• Memento
• Observer
• State
• Template Method
• Visitor

Advantages of using software design templates

One can look at the design of patterns with the view that using them is, in fact, benefiting from the experience and expertise of the best object-oriented programmers in the coding process. Some believe that problems such as overuse of classes, poor design, etc. are among the fundamental problems of object-oriented programming. Pattern designs provide many benefits to programmers by properly understanding the principles of object-oriented programming. Among the most important benefits of using them can be mentioned the following:

• Increase scalability
• Increase flexibility
• Speed ​​up software development
• Reduce errors and problems
• Reduce coding rate

When and where should we use design patterns?

Knowing when and where to use design templates is a common question among programmers. Since each design pattern is provided for a specific application and to solve a specific problem in the programming process, we must be able to identify those problems during software development. After identifying and diagnosing such problems, we need to learn how to use the design patterns provided to solve them so that we can use them.

Conclusion

Understanding the concepts of design patterns is a must for all programmers. Because design templates are provided with the aim of solving common coding problems and standardizing the software development process. Using design patterns, programmers are able to build flexible, scalable, and scalable software that is designed to be principled. Have you ever used design patterns? What do you think is the most important advantage of using design patterns in object-oriented coding?