Introduction to Software Design Patterns

Software development cycle involves many phases like requirement analysis, feasibility study, UI design, UML class diagrams, software coding, Testing, etc. 

Software Design Patterns plays a significant role in the Software coding or programming phase.  

Writing code is the simplest process if we follow the design patterns. Anyone can write code, but better software comes only if we follow design patterns. 

Software code changes regularly. There is no constant or defined code for a use case. Technology is getting updated every day. So the software needs to be updated with the technology advancements. So the code should be written in such a way it can be easily updated with less effort.

It’s effortless to write a new piece of code instead of changing in the legacy code. If you want to change or update in the legacy code, then you need to know the complete logic of that fragment of code.

 We can say our software is flexible and adaptable only if anyone can update the legacy code at any point of time without any hassle. Software product company always focus on the design and architecture of the application. If you have written code without proper design and architecture, then it’s a time bomb in the future. 

Designing software takes more time than implementation, but it’s worth to spend that time. While designing software you need to break down the complex design into atomic components. Each component should be easily replaceable and updatable.

You need to design your software from scratch, but you can follow the existing Software Design Patterns for common use cases. 

Table of Contents

What are Software Design Patterns?

In Software Engineering, Software Design Patterns plays a vital role in the Software development. Software Design Patterns solves the commonly occurring problems of software development.

A Design Pattern represents the best practices followed by experienced software developers.

The concept of Design Pattern holds great importance so, it must be learned in the initial stages of Software Development.

Software experienced people identified the problems in software development. They have grouped those problems into some common solution buckets.

The problem in software design is solved by using the existing Software Design Patterns.

Software developers need to be very smart which means use existing solutions instead of reinventing solutions for the existing problem patterns. This helps the software developers to focus on their business use cases.

In the past, Software developers were facing similar kind of problems and the solutions for those also very similar. That has resulted in Software Design Patterns.

Software Design Patterns Definition

Design patterns constitute a set of rules describing how to accomplish certain tasks in the realm of Software Development. Pree 1994

Design patterns are recurring solutions to design problems you see over and over – Smalltalk Companion

Real-time Examples for Software Design Patterns

clock photoWe do some everyday activities daily like brushing, bathing, eating, working, etc. Let’s suppose if you are a student; you follow these activities daily in the repeat mode. You get up early in the morning, you do some meditation, you study for some time, you brush up and bath, you go to school and spend 8 hours in the house, you return to home and play for some time, you start studying, you watch TV, and finally you go to bed. The same process repeats for the next day also. So these are the patterns in real life.

There could be many patterns for the Student use case. You would have been following any of those patterns. If you face any issues in your day to day activities, you will try to solve the problem by figuring out the problem in a detailed manner.

For Example, you are poor in Mathematics that’s your problem. Let’s consider; your friend also had the same problem; he had overcome his problem by joining in a tuition class. Here, the solution to your problem is already existing. So you would try to follow the same solution.

lunch photoPeople suggest the ideal timings for lunch and dinner from 1 pm to 2 pm and 7 pm to 8 pm. Similarly, the experts in software development suggest that the perfect way to make a program reliable and to make a software perform at its best is to follow these “Design Patterns” because the primary motive behind design patterns is to make the program a best one.

Foundation of Design Patterns

The concept of design patterns originated from Christopher who was an architect. He applied the design patterns concept for buildings. He analyzed various things like Environment, Soil condition, Land area, etc and came up with patterns for the building. So if the use case falls into the existing patterns, he used to follow the existing solution instead of reinventing a new one. This saved his time and effort.

The software field is in the movement for the last 40 years. At that time people used to see many “use cases”. They used to solve those real-world problems using some solution, and they kept grouping those solutions in templates. Those templates were named Design Patterns. For example, if there is some common solution for N number of problems, they will try to treat it as a design. We need to follow that design if our used case falls in that category.

Four people introduced design Patterns. Erich, Richard, Ralph and John and they published a book called Design patterns elements of the useful “object-oriented” software in 1994. This book covers two things.

They followed most of the principles which are in Object-Oriented.

The first part covers the pros and cons of object-oriented programming and the second part covers twenty-three design patterns.

Many books covered the first part but the second part is unique. At that time these four people stood out from the other people because of this second part covering twenty-three design patterns. 

These twenty-three design patterns are divided into three parts: Creational design pattern, Structural design pattern and Behavioral design pattern. 

They hadn’t recommended these patterns to a specific programming language. You can follow these patterns if you are developing in Java, C++, etc. 

Software Design Pattern Categories

  • It will help to create objects by hiding the creation logic.
  • It covers object creation and initialization.
  • For example, in case of software object-oriented programming, we need to place some objects for our real-world use case and then we need to communicate with an object from other objects which will be handled using Creational design pattern
  • It focuses on class and object composition.
  • It is like USB interface, and we have the implementations for USB.
  • We need to loosely couple the interface and implementation. If your software modules are loosely coupled, then your software is more reliable and more outstanding from other things.
  • It focuses on the communication between the objects and dependency between objects.
  • So, if suppose there is a class, and for that class, we have created a file object. If that file object needs to communicate with the class thing so the communication between class and object will be handled in the Behavioral design pattern

Software Design Patterns Uses

By learning these design pattern, you can easily pick the best pattern for your use case. 

If the existing patterns don’t solve your use case, you would be experienced enough to create a new design pattern. 

You can suggest the design pattern that was created by you to your colleagues also. So they can use that if they handle similar kind of use cases. That’s the power of design patterns.

Advantages of Software Design Patterns

  • It helps software developers to reuse the solution template for common problems which in turn helps them to save time and money.
  • Software experienced people designed these design patterns. They had used all their experience to come up with these patterns so the software quality would be better if we follow the design patterns.
  • It would be a better starter guide for newbies in the software field.
  • Reinventing the wheel is the worst in most of the fields especially in the software field. These patterns will help us to overcome this issue.
  • The class design would be clean since these patterns focus mostly on Object-Oriented principles.
  • It helps software developers to communicate easily with their teammates. Example: I followed “Singleton Design Pattern” because of so so reasons.
  • It improves maintainability and modifiability of code. Your teammates can easily change the code that you had written years before.

Tutorial Videos of Software Design Patterns

Software Design Patterns Introduction in English, Tamil and Telugu

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