Design pattern: what is it and why use it?

The design pattern is an essential element in object-oriented programming.


It is a software infrastructure made up of a small number of classes that is used to solve a technical problem.


To understand what it is, here is what the design pattern is and why it should be used.

Fixing known design problems

Design pattern has its origin in the fact that developers have noticed recurring and similar design problems. Therefore, it became necessary to conceptualize design problems in such a way that the same answers were reused each time the problem arose.

To conceptualize, it is often essential to use code directly. But in the case of the design pattern, developers translate the conceptualization into an abstract idea of how to solve the problem. Each developer then implements the problem resolution using the language they are familiar with. There are examples of design pattern applications for different languages.

The design pattern is therefore conceived as a general design process that builds on the experience already acquired in software design. The design pattern has an important role to play in the computer system and its architecture.

The origin of the design pattern

The design pattern comes from the field of architecture. The concept is mainly indebted to Christopher Alexander. This design pattern concept allows to create applications in the process of designing shapes. The idea has not only been adopted in architecture, but also in anthropology, art history and of course in computer science.

It was more precisely in 1987 that Kent Beck and Ward Cunningham discovered that the design pattern could be applied to programming. They developed the concept in such a way as to ensure its application to known problems.

The concept was further clarified and adopted more widely in the community with the publication of the book Design Patterns: Elements of Reusable Object-Oriented Software in 1994. The book is authored by the Gang of 4, or GoF, composed of Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides. The book introduces and disseminates the concept that will be increasingly adopted by developers.

Why use a design pattern?

The usefulness of using a design pattern is obvious. The design pattern can accelerate the development process. It provides proven development paradigms, which helps save time without having to reinvent patterns every time a problem arises.

Because the design pattern is created to fix known problems, they can be predicted before they become visible during the implementation process. Again, the design pattern speeds up the development process. Standardization related to the design pattern is also very useful to facilitate code readability.

In short, the design pattern is useful when moving from an analysis model to a development model. It can be used in a concrete way in several cases, in particular for managing the payroll system when changing a salary and keeping the system informed of the changes this implies.

Thanks to the design pattern, it is possible to document the solutions to be adopted based on previous practices and lessons learned. Several software components are used in the implementation of the design pattern. The model therefore speeds up a process that involves several components. Developers use the language they are familiar with in the application of each solution.

Shared knowledge

Both the computer architect and the programmer are called upon to use the same language in relation to the design pattern. The computer architect only has to give the name of the design pattern type so that the programmer understands what it is about. There will be no need for lengthy explanations. It is therefore important for professionals to know what the main design patterns consist of.

The design pattern can be used at all stages of programming work. It can be used before since it can be used as a guide in writing the source code. It is also frequently used after the programming work since its effectiveness allows it to be used as a template to link existing source code modules.

Of course, the design pattern is very useful during programming since it can establish commonalities with existing models, which will help avoid and anticipate errors. Most of the time, the design pattern is used when it is clear that the developer needs its flexibility.

Each design pattern has its own approach. The strategies present in each design pattern are therefore original and are never the same from one design pattern to another. In this way, it is possible to solve each problem in an organized and fast way. Just apply the right design pattern, which has already proven itself. It is also possible to combine patterns in the development of a solution.


Different varieties of design patterns

There are several design patterns and new ones are constantly being created as needed. One example is the composite model, which is used to implement a tree structure. This can be a representation of a folder with its sub-folders and the files found in them. Sheets and composites follow a model that uses the same software interface. The handling is the same for each use.

The model eliminates the need to distinguish between primitive objects and containers. Individual objects and their combinations are treated in the same way.

Another important model is the singleton. It limits the instantiation of a class to a single object. It is used so that a single object coordinates operation within a given system. It is mostly used for a system that is faster or takes up less memory. It is also a system with few objects. Iterators and adapters are also among the main design patterns.

Iterators allow access to the elements of a set without necessarily having knowledge of the technical details related to it. This is one of the most frequently used design patterns.

As for the adapter, it allows converting one interface into another, which is exploited by an application. Thanks to this model, it is possible to connect together interfaces that were incompatible at first sight. This is also a frequently used procedure.

The anti-pattern

Beware of anti-pattern, which is an anti-pattern that is an inadequate response to a recurring problem.

It is therefore a solution that is reinvented in the wrong way in response to the recurring problem. There are ways to distinguish an anti-pattern from an occasional bad practice.

An anti-pattern is a commonly used structure that generates bad consequences even if it seemed effective at first.

Instead of an anti-pattern, there is always an applicable solution that fits the design pattern and having professionals like Ryax help you implement the right solution.

The Ryax Team.