When there is a hierarchical structure, there are 2 types of components Leaf nodes and Composite nodes. Usually in this type of scenario, we will have to check which type the component is before performing some action on them using an if-else block. The composite pattern provides us a way…

The Template Method Pattern: defines the skeleton of an algorithm in a method, deferring some steps to subclasses. The template method lets subclasses redefine certain steps of an algorithm without changing the algorithm’s structure. Abstract class has a method called Template method which contains the structure of the algorithm but…

Definition: The command pattern encapsulates a request as an object, thereby letting you parameterize other objects with different requests, queue or log requests, and support undoable operations. Command public class LightOnCommand implements Command { Light light; public LightOnCommand(Light light) {…

Change is the inevitable character of anything and software is no exception. The job of a good engineer is to design the systems in a way to cope up with the change and for it to be maintainable. We have enough examples of codebases becoming unmaintainable after a few years…

The observer pattern defines a one to many dependencies between objects so that when one object changes state all of its dependents are notified and updated automatically This provides an object design where subjects and observers are loosely coupled: They interact but have very little knowledge of each other making…

Encapsulate what changes: Object instantiation is something that is more prone to change. When a new type of object need to be added to extend functionality it will change. Encapsulating these changing parts is what we are focused on here. All factory patterns encapsulate the object creation Also, both the…

When in a software project, need comes to extend the behavior of the product by adding new functionalities, we could use inheritance by subclassing to extend the behavior of an object. But then inheritance is done at compile-time and methods are also available for other instances of that class. Because…

SOLID is an important set of principles in OOP software development and the name is an acronym for the five principles it explains. 1. Single Responsibility Principle The idea of this principle sounds simpler than it actually is and it says that a class should do one thing. …

Apps nowadays need to meet the requirement of being robust and responsive. RxAndroid and Kotlin tools are equipped to help this process. They will help us take our apps to the next level. Reactive vs Imperative Programming Following are some characteristics of Reactive Apps Responsive: Makes the UI thread is responsive so that the…