Showing posts from 2021

SOLID Principle (Quick Read)

 The famous design principle comprises 5 design strategies that a developer should follow for a successful application development Single Responsibility Principle Open/ Close Principle Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Single Responsibility Principle(SRP) No code unit(function/class/package) should have more than one responsibility.   Bad Ex:   Class Bird  {     String result;;    public fly(Bird bird)    {     if(bird==piegeon)       result="flys 20 meter hight";    else if(bird==hen)       result="flys 5 meter";    else        result="not measured yet";    } } This class should design such a way that it should work well for all the types of birds current design is hectic to maintain for the following reasons  difficult to test. difficult in parallel programming  understanding the code is difficult solution: Break the code into multiple packages or classes How to identify SRP is violated(Litmus test to SRP)

Microservice -Cloud Configurations -Spring

 Let's explore the Microservice deployments ,registration using Service Registry and controlling the communication using APIGateways in next blog. Will create a microservice Library using H2 databass fro the persistance. The entire codebase will be shared in the git will share at the end of the blog. Let's create the Books microservices like below Controller  Services Repository  Entity   application.yaml server : port : 9000 Postman test output Create the Books microservices the same way. Refer to the code from the end. Mail goal is to access using the gateway service Big Step Going to add the microservices to the Service Registry to do that create one more microservices with the below dependency < dependencies > < dependency > < groupId ></ groupId > < artifactId >spring-cloud-starter-netflix-eureka-server</ artifactId > </ dependency > < dependency > < groupId >org.spr

JAVA 8 Predefined Functions

 Java 8 has considerable up-gradation when compare to other releases, I am going to discuss some key concepts that are very much required for the understanding of functional programming way of implementation. I have written one Demo problem which covers all the concepts, better refer to  this code  while reading. Better to understand what is lamdas, default methods, and static methods, this article will be a quick reference. 👍 4 Key Predefined Functions Interfaces 1.) Predicate 2.)Function 3.)Consumer 4.)Supplier 1.)Predicate I nterface Predicate<T> { boolean test(T  t);// functional interface  default Predicate<T> add(); default Predicate<T> or();  default Predicate<T> negate()  static <T> Predicate<T> isEqual(Object targetRef) ====>single static method } This predicate is mainly used for the conditions check, which contains a single abstract method, 3 default methods, and single static methods. Single Abstract Method test(T k); This method will