Tag: Java Design Pattern

Introduction In this tutorial I am going to discuss about best practices while building applications using Spring framework. Recently Spring has been one of the most popular Java based framework for building enterprise applications. Anyone can grasp the basic concepts and starts building applications using Spring right away but to become a strong developer you…

Composition vs Aggregation explained with Java will show you what is Composition and what is Aggregation? In simple terms, both Composition and Aggregation are Associations. Composition means “Strong Has-A relationship”, whereas, Aggregation means “Weak Has-A relationship”. Composition implies a relationship where the child cannot exist independently without the parent. Example: House (parent) and Room (child). Room doesn’t…

Introduction State pattern comes under behavior design pattern in JEE. The State design pattern allows an object to alter its behavior when its internal state changes. State pattern is used to provide a systematic and lose-coupled way to achieve this through Context and State implementations. Context is the class that has a state reference to…

Introduction The strategy pattern is a behavioral design pattern that enables an algorithm’s behavior to be selected at runtime without causing tight coupling. The strategy pattern defines a family of algorithms, encapsulates each algorithm, and makes algorithms interchangeable. Strategy pattern lets the algorithm vary independently from clients that use it. So you define a strategy…

Observer Pattern is one of the behavioral patterns. Observer design pattern is useful when there is something need to be done with the state of an object and an object wants to get notified whenever there is any change in state. In observer pattern, the object that watches on the state of another object are…

Table of Contents Introduction Prerequisites Memento Design Pattern Implementation Main Class Output Source Code Introduction Memento Pattern is one of the behavioral patterns. Memento pattern is a software design pattern that provides the ability to restore state of an object to its previous state. The memento design pattern is implemented with three objects: the originator,…

Mediator Pattern is one of the behavioral patterns as it deals with the behavior of the program. Usually a program is made up of a large number of classes. So the logic and computation are distributed among these classes. As more classes are developed in a program, the number of classes are increased, thus arising…

Iterator pattern falls under behavioral design pattern. Iterator pattern is very commonly used design pattern in Java. This pattern is used to iterate through a collection of objects without exposing its underlying representation. It is used to access the elements of an aggregate object sequentially. For example, Java’s collections like ArrayList and HashMap have implemented…

The command pattern comes under behavioral design pattern. The Command pattern is used to create objects that represent actions and events in an application. In the command pattern, a command interface declares a method for executing a particular action. A command object encapsulates an action or event and contains all information required to understand the…

The Chain of Responsibility is known as a behavioral pattern, as it is used to manage algorithms, relationships and responsibilities between objects. The Chain of Responsibility pattern consists of a series of processing objects where each object containing the type of commands it can handle. Each object in the series either does its own task…

Table of Contents Introduction Use Cases Proxy Pattern Example Proxy Pattern Class Diagram Prerequisites Project Setup Proxy Interface Proxy Implementation Proxy Class Service Class Proxy Example Source Code Introduction The Proxy is known as a structural pattern, as it is used to form large object structures across many disparate objects. It functions as an interface…

This design pattern comes under structural pattern as this pattern adds an interface to the existing system to hide all its complexities. As the name suggests Facade means the face of the building block. The real life examples of this pattern can be explained as explained below : We know that Computer system starts up…