Programs

Top 5 Important Software Design Patterns in 2022

Software design patterns are among the most frequently discussed topics in the tech community, especially developers. They believe that if a software design pattern is overused, the code will be tricky for others, particularly if they do not understand the patterns. 

To redo the code and make it more innovative, one must understand the different types of design patterns used in developing software. Although there are not many patterns, understanding them can help you in the long run.

What are Design Patterns in Software Development?

Software design patterns are templates used in software development. However, they are not meant for project development. Instead, they are helpful in problem-solving, which can lead to the development of efficient software. In other words, design patterns are reusable solutions that assist in creating the application but do not possess the actual code needed to build the application.

Design patterns ultimately make the code robust and readable since they are thoroughly tried and tested. Hence, using them is considered a best practice. Using programming design patterns assists developers in giving the code flexibility and reusability.

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Why Do Developers Use Software Architecture Patterns?

Developers prefer to use design patterns for a variety of reasons. For example, it assists them in solving code issues. However, design patterns cannot be used as a shortcut to software development. 

However, design patterns can greatly enhance the quality of the software if used correctly. Design patterns offer developers a common language to discuss and resolve problems. When a design pattern is used strategically, it provides developers with sophisticated solutions to existing applications.

Top 5 Software Design Patterns

1. Singleton or Creational Design Pattern

The singleton or creational design pattern is used for an object or class creation. It works best when there is a need for one object to trigger coordinated actions in the system. For example, one instance can be created with an object called the longer. This is referred to as the getinstance method. With this method, the logger will output the relevant information once the object is obtained. Thus, reducing the amount of code that would have been used otherwise.

Initiating one object per class is no trivial task. However, developers should ensure that no more than one object is created. For this, developers must ensure that the constructor retains the self-reference. This way, if it is the initial instance, it may generate itself or return an already built reference if it has been initiated elsewhere in the program.

Developers can create subclasses from a singleton design pattern by declaring a protected constructor. Another way of creating a subclass is by creating a register of the subclasses in the design pattern. When parameters are given to getinstance, an environment variable can return the relevant singleton pattern.

public class SingletonSample {

   private static SingletonSample instance = null;

 

   private SingletonSample() {

   }

 

   public static SingletonSample getInstance() {

      if(instance == null) {

         instance = new SingletonSample();

      }

      return instance;

   }

The registry is used to keep track of singleton object mappings to string names and vice versa, which can be retrieved as needed. Top examples of the creational design pattern include thread pools, caching and logging, etc. This design pattern is versatile and may be used in conjunction with many other sophisticated designs.

2. Factory Design Pattern

Considered as one of the top design patterns, software developers use this to create objects without actually having to reveal the logic of the code. Just like how things work in a factory, goods are produced. However, in tech terms, the software factory creates objects called classes. Here, the class of the object need not be specified.

This can be achieved using the factory method instead of the constructor. However, this method is inefficient as the constructor generally uses the AbcClass component. Using the factory method gives developers the leniency to create many dynamic ‘types’. For example, a game with several monsters has its unique attack methods to attack the player. These can be created dynamically with this code: monsterFactory.new(‘monsterType’).

3. Decorator Design Pattern

This design pattern is most effective when an additional class is required. For example, assume you have opened a pizza parlor with only two types of pizza: cheese and meat. Your billing system is only set up to handle these two categories. However, when customers begin to arrive, you receive several requests for extra add-ons such as more cheese or different toppings. This can cause the billing system of the restaurant to become haywire. Here, the solution would be asking an IT guy to create subclasses for the extra requests.

// Sample getCost() in super class

public int getCost()

{

    int totalToppingsCost = 0;

    if (hasJalapeno() )

        totalToppingsCost += jalapenoCost;

    if (hasCapsicum() )

        totalToppingsCost += capsicumCost;

    // similarly for other toppings

    return totalToppingsCost;

When requests come in, you can create multiple subclasses. Relatively, the amount of coding required would increase as well. The decorator design pattern can help developers in limiting the number of subclasses.

4. Adapter Design Pattern

By enabling interfacing between different classes, this software design pattern allows previously incompatible classes to function together. We can use the example of a translator to illustrate this. When two leaders from different nations meet and speak different languages, they communicate via a shared medium, the translator. The adapter, in this case, is the translator, which allows both ends to exchange relevant information. If there are two software with two different outputs, the adapter’s job is to guarantee that the two software will interact effortlessly.

5. Observer Design Pattern

The observer design pattern is based on the affinity between the objects. The change of state notifies all the dependents in the pattern. This is called the observer method, which is programmed in the classes. This pattern assists developers in creating objects with multiple dependencies.

There are a few things to consider before implementing this pattern in the architecture of the software. First, the dependent and its functions must be identified. Abstractions must be provided to the independent classes. After that, the dependents must be placed according to their hierarchies. The subjects are then paired with the principal observer class. The observers identify with the objects, and the observer classes are updated on their respective state changes via the objects.

This is a more complicated notion than the others, but it allows for more dynamic systems that must adapt to events regularly. Therefore, it is crucial to choose the dependency chain while utilizing the observer design pattern. Developers should also choose the senders and receivers in the design phase itself. This makes the code easier to comprehend and modify later, if necessary.

Benefits of Using Design Patterns

Design patterns standardize the code and allow developers to follow the best programming practices called coupling and cohesion.

Coupling: Coupling refers to the dependency between software components. When two components interact, information is exchanged. While high coupling can lead to the code becoming complex, dependency cannot be removed since the components interact with each other. The indication of a good code is low coupling. 

Cohesion: Cohesion refers to the build quality and the focus of the code. All relevant software data must be in the same class. Accessibility can be controlled when all the functions are grouped together. This makes the code robust, which leads to lesser complexity and higher maintainability.

Conclusion

Software design patterns are essential for developers who wish to create a robust application architecture. More than theory, it is a practical approach to how the developers implement the patterns in their code.

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What are design patterns in software engineering?

Design patterns in software engineering are comprehensive, reusable blocks of code that are used to tackle common programming problems when developing applications. Singleton, Factory Design, and Adapter are a few most used software design patterns.

In practice, how many design patterns are there in software development?

As per Design Patterns - Elements of Reusable Object-Oriented Software, the 1994 book by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, software engineering has 23 design patterns that can be broken down into three categories - Creational, Structural and Behavioral patterns. There is an additional category of design patterns namely J2EE design patterns.

How do we decide which design pattern is applicable for a given software problem?

Begin with understanding how design patterns help address design problems and how different design patterns interrelate. Thereafter, developers must go through the intent sections of an application, analyze the purpose of study patterns to match the problem at hand, and examine what is the need for redesigning.

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