Encapsulating Algorithms — Overview We’re on an encapsulation roll; we’ve encapsulated object creation, method invocation, complex interfaces, ducks, pizzas…what could be next? We’re going to get down to encapsulating pieces of algorithms so that subclasses can hook themselves right into a computation anytime they want. In this chapter, we will talk about another behavioral…

Being Adaptive and simplify interfaces — Overview Welcome to another post on the design pattern series! In this chapter, we’re going to attempt some features such as putting a square peg in a round hole. Sound impossible? Not when we have Design Patterns. Remember the Decorator Pattern? We wrapped objects to give them new responsibilities. Now we’re…

Let’s encapsulate method invocation — Overview Welcome to another post on the design pattern series! In this chapter, we take encapsulation to a whole new level: we’re going to encapsulate method invocation. The Command Design Pattern is a powerful behavioral pattern that allows developers to encapsulate a request or action as an object, thereby promoting loose…

It can easily go wrong than you might think of — Overview Singleton Pattern has the simplest structure among all the design patterns, but it isn’t easy to implement it correctly. The Singleton Pattern is a popular design pattern that ensures a class has only one instance and provides a global point of access to that instance. It is particularly useful when…

Creating objects with factories — Overview Welcome to the fourth chapter of this design patterns series. Let’s first review the design principles we have learned. Encapsulate what changes Program to interface, not implementation Favor composition over inheritance Loosely coupled designs between objects that interact Open/Closed principle In this post, we will be learning another two creational…

Extension at runtime, rather than at compile time — Overview Let’s review the four OO design principles in the introduction and observer pattern chapters as they are the building blocks to support our design patterns. Encapsulate what changes Program to interface, not implementation Favor composition over inheritance Loosely coupled designs between objects that interact In this post, we will be…

Keeping your objects in the know — Overview In the first post of this design pattern series, we introduced three design principles and a design pattern (strategy pattern). In this post, we will learn the fourth design principle and another behavior design pattern — Observer Pattern. The Observer Pattern defines a one-to-many dependency between objects so that when…

Why do design patterns matter in the first place? — Overview Many developers may argue they know well about OO concepts like Abstraction, Encapsulation, Polymorphism, and Inheritance and can apply them to real code pretty well, what’s the point of knowing the academic design patterns which seem abstract and isn’t straightforward to apply in real code? Think about the data structures…

Get to know more about Log4j2 and SLF4J — Overview In the previous post, we introduced some of the most commonly used logging frameworks in Java including JUL, SLF4J, Logback, Log4J, Log4J2, in which SLF4J is a special one that provides a simple facade or wrapper API over different logging frameworks. …