Software design patterns are a huge source of discussion among peers. If you want to experience the same, then just jolt a question on a tech platform. For example, a post on Reddit had more than fifteen comments; all said one thing, software design patterns are not about rigidity!

Refactoring your software design pattern does help you to be more innovative with products. But, if your goal is to reach the ultimate, what design patterns should you learn? 

There are only a handful of software design patterns to upgrade your knowledge when it comes to getting a job from giants like Google or Facebook. But, before we explore different patterns, let’s understand what is a design pattern!

Keep on reading to find the right answer to your question, what is the best approach in design patterns in coding? The following article will also talk about the different design patterns in Java.

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What is a Software Design Pattern?

Software design patterns are reusable solutions that are not exactly the final product. It is a type of template for software design. They are not a code that can be directly converted into the software. 

Take an example of different clothing styles like denim, striped shirts, or even chinos. They are all templates based on which we can create new clothes, but they are not a final product.

Software design patterns are often the context to which a machine code is created. They can be repetitive, but never the same. It is not coded itself the can be reused.and instead an architecture to build new solutions.

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Why do we need a Design Pattern?

If you are a software developer thinking of upgrading your skill through new software design patterns, then the first thing to consider is flexibility. A design pattern should be able to infuse flexibility into your software.

The idea behind flexibility is the relevance of attributes. The features that you envisage earlier on will not remain the same over the period, and you will need tweaks to induce new functionalities. Here, a software design pattern can help you make further changes. So, let’s look at the five most popular software design patterns you should learn.

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Top 5 Popular Software Design Patterns

Creational/Singleton

The sole purpose of a singleton/creational software design pattern is to create a single purpose instance. Take an example of a calendar; it is a software program that can make only one instance of a class and does not allow other cases. It uses a getInstance() to get the object.

But, the question here is,

How do you stop others from creating different instances?

Here, the singleton design induces a private constructor. So, all the members will have access to the constructor only, which will enforce the creation of a single class. The class provides a global access point, for instance. 

Such a software design pattern is used for logging, thread pool, driver objects, and caching. 

The Java singleton pattern is interoperable and works well within other advanced designs.

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2. Decorator

A decorator or structural design pattern is best when you need add-on class. For example, you start a pizza restaurant with two main types, margarita and double-cheese pizzas. Once the customers start coming in, they demand add-ons like mushrooms, onions, and even some jalapeno. So, your billing system is almost fried.

Your IT guy creates a subclass for add-ons like jalapenos, onions, and mushrooms to save the day. But, just when you think life is sorted, a competitor opens a new restaurant on the opposite side of the street with subclasses for corns, olives, etc. 

With a new competitor, the number of subclasses you will need to create an effective billing system can go overboard. Think of creating 300 plus subclasses, and the level of coding behind it. The decorator pattern helps reduce the subclass count to around 16. It also leverages the abstract component for the creation of the structural design.

3. Command Design Pattern

A command design pattern focuses on how different classes and objects behave mutually. Because mutual behavior can affect the software system’s response to user requests, any loosely coupled action can disrupt the software’s functionality, and this pattern helps identify such errors. 

A coupling between the class and the object helps determine the dependency. Now a loose coupling will indicate non-dependency among class and object. It introduces an invoke-command that helps execute the action dependant on a specific class. For example, you want to order food, and the waiter will be your invoker to help you get the object(food).

4. Factory Design Pattern

One of the most popular design patterns used by software developers is a factory method. It is a creational pattern that helps create an object without the user getting exposed to creational logic. 

The only problem with a factory method is it relies on the concrete component. What happens is when you use a factory method, there is no specific definition of class. So, instead of the constructor class, Someclass is used. Creating a new object is coupled with the concrete component that can have issues with such a class.

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5. The Observer Pattern

An observer pattern helps create multiple dependencies. So, when one object changes the state, every dependent is informed. But, before you apply the famous observer pattern for your next software architecture, here is what to consider.

• Identify the independent functionalities and the dependent ones.
• Provide a “subject” abstract to each independent function
• Place the dependent “subject” in the observer hierarchy.
• The subject is coupled with an observer class.
• All the observers in the hierarchy register to the subject
• Every observer is informed about the change of state through the subject.

The essential part of executing an observer pattern is to decide the chain of dependency. It is also quite crucial to assign sender and receiver at the endpoints of the hierarchy. 

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6. Strategy

Strategy is yet another one of the top 7 software design patterns. It basically allows grouping related algorithms under an abstraction. This in turn helps to switch out any one algorithm or policy for another, without the need to modify the client. To put it simply, under the strategy pattern, the code receives runtime instructions that specify which of the group of algorithms need to be run. This eliminates the need for directly implementing a single algorithm.

7. Builder

Builder pattern is basically used for building objects. Especially in cases where the created objects tend to be complex because of the use of several sub-objects or an elaborate construction process, the builder pattern helps to simplify the process of creating complex types. As the name suggests itself, the builder pattern helps to build a comprise or an aggregate object. 

One of the most common misconceptions about this software design pattern is that it is similar to the abstract factory pattern. However, one of the major points of differentiations between these software design patterns is that, while the builder pattern builds objects step by step, the abstract factory pattern does the complete opposite. It returns the object in one go. 

Design Patterns In Java

Hopefully, the above-mentioned article has answered your question of what is the best approach in design patterns in coding? Moving on, let’s take a look at some of the design patterns in Java, that are considered to be the best. 

There are typically three types of design patterns in Java, each accompanied by its own subsets. The same has been listed below. 

• Creational Design Pattern- As the name suggests itself, creational design pattern mainly deals with the different ways of creating an object. Especially in situations where a decision has to be made for creating an object of a class, this design pattern is used. The subsets of this pattern are as follows, Factory Pattern, Abstract Factory Pattern, Prototype Pattern, Singleton Pattern, and Builder Pattern. 
• The second design pattern used in Core Java is the Structural Design Pattern which is basically responsible for simplifying the design of a large object structure. It does so by identifying relationships between them. Some of the subsets included under this pattern are, Decorator Pattern, Facade Pattern, Proxy Pattern, and Adapter Pattern, among others. 
• Last but not least, is the Behavioral Design Pattern which is used in Core Java. Behavioral Design Pattern deals with the strategy of object collaboration. It also is responsible for the delegation of responsibilities among the objects. 

Conclusion

Software design patterns can help you as a programmer to create robust architectures. But, you need to have the right knowledge to use them. It is not about the theoretical study, but more of a practical approach.

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