The MVC design pattern is a software architecture pattern that separates an application into three main components: Model, View, and Controller, making it easier to manage and maintain the codebase. It also allows for the reusability of components and promotes a more modular approach to software development.
What is the MVC Design Pattern?
The Model View Controller (MVC) design pattern specifies that an application consists of a data model, presentation information, and control information. The pattern requires that each of these be separated into different objects.
- The MVC pattern separates the concerns of an application into three distinct components, each responsible for a specific aspect of the application’s functionality.
- This separation of concerns makes the application easier to maintain and extend, as changes to one component do not require changes to the other components.
Why use MVC Design Pattern?
The MVC (Model-View-Controller) design pattern breaks an application into three parts: the Model (which handles data), the View (which is what users see), and the Controller (which connects the two). This makes it easier to work on each part separately, so you can update or fix things without messing up the whole app. It helps developers add new features smoothly, makes testing simpler, and allows for better user interfaces. Overall, MVC helps keep everything organized and improves the quality of the software.
Components of the MVC Design Pattern
1. Model
The Model component in the MVC (Model-View-Controller) design pattern demonstrates the data and business logic of an application. It is responsible for managing the application’s data, processing business rules, and responding to requests for information from other components, such as the View and the Controller.
2. View
Displays the data from the Model to the user and sends user inputs to the Controller. It is passive and does not directly interact with the Model. Instead, it receives data from the Model and sends user inputs to the Controller for processing.
3. Controller
Controller acts as an intermediary between the Model and the View. It handles user input and updates the Model accordingly and updates the View to reflect changes in the Model. It contains application logic, such as input validation and data transformation.
Communication between the Components
This below communication flow ensures that each component is responsible for a specific aspect of the application’s functionality, leading to a more maintainable and scalable architecture
- User Interaction with View: The user interacts with the View, such as clicking a button or entering text into a form.
- View Receives User Input: The View receives the user input and forwards it to the Controller.
- Controller Processes User Input: The Controller receives the user input from the View. It interprets the input, performs any necessary operations (such as updating the Model), and decides how to respond.
- Controller Updates Model: The Controller updates the Model based on the user input or application logic.
- Model Notifies View of Changes: If the Model changes, it notifies the View.
- View Requests Data from Model: The View requests data from the Model to update its display.
- Controller Updates View: The Controller updates the View based on the changes in the Model or in response to user input.
- View Renders Updated UI: The View renders the updated UI based on the changes made by the Controller.
Example of the MVC Design Pattern
Below is the code of above problem statement using MVC Design Pattern:
Let’s break down into the component wise code:
.webp)
1. Model (Student class)
Represents the data (student’s name and roll number) and provides methods to access and modify this data.
Java class Student { private String rollNo; private String name; public String getRollNo() { return rollNo; } public void setRollNo(String rollNo) { this.rollNo = rollNo; } public String getName() { return name; } public void setName(String name) { this.name = name; } } 2. View (StudentView class)
Represents how the data (student details) should be displayed to the user. Contains a method (printStudentDetails) to print the student’s name and roll number.
Java class StudentView { public void printStudentDetails(String studentName, String studentRollNo) { System.out.println("Student:"); System.out.println("Name: " + studentName); System.out.println("Roll No: " + studentRollNo); } } 3. Controller (StudentController class)
Acts as an intermediary between the Model and the View. Contains references to the Model and View objects. Provides methods to update the Model (e.g., setStudentName, setStudentRollNo) and to update the View (updateView).
Java class StudentController { private Student model; private StudentView view; public StudentController(Student model, StudentView view) { this.model = model; this.view = view; } public void setStudentName(String name) { model.setName(name); } public String getStudentName() { return model.getName(); } public void setStudentRollNo(String rollNo) { model.setRollNo(rollNo); } public String getStudentRollNo() { return model.getRollNo(); } public void updateView() { view.printStudentDetails(model.getName(), model.getRollNo()); } } Complete code for the above example
Below is the complete code for the above example:
Java class Student { private String rollNo; private String name; public String getRollNo() { return rollNo; } public void setRollNo(String rollNo) { this.rollNo = rollNo; } public String getName() { return name; } public void setName(String name) { this.name = name; } } class StudentView { public void printStudentDetails(String studentName, String studentRollNo) { System.out.println("Student:"); System.out.println("Name: " + studentName); System.out.println("Roll No: " + studentRollNo); } } class StudentController { private Student model; private StudentView view; public StudentController(Student model, StudentView view) { this.model = model; this.view = view; } public void setStudentName(String name) { model.setName(name); } public String getStudentName() { return model.getName(); } public void setStudentRollNo(String rollNo) { model.setRollNo(rollNo); } public String getStudentRollNo() { return model.getRollNo(); } public void updateView() { view.printStudentDetails(model.getName(), model.getRollNo()); } } public class MVCPattern { public static void main(String[] args) { Student model = retriveStudentFromDatabase(); StudentView view = new StudentView(); StudentController controller = new StudentController(model, view); controller.updateView(); controller.setStudentName("Vikram Sharma"); controller.updateView(); } private static Student retriveStudentFromDatabase() { Student student = new Student(); student.setName("Lokesh Sharma"); student.setRollNo("15UCS157"); return student; } } Student: Name: Lokesh Sharma Roll No: 15UCS157 Student: Name: Vikram Sharma Roll No: 15UCS157
When to Use the MVC Design Pattern
Below is when to use MVC Design Pattern:
- Complex Applications: Use MVC for apps with many features and user interactions, like e-commerce sites. It helps organize code and manage complexity.
- Frequent UI Changes: If the UI needs regular updates, MVC allows changes to the View without affecting the underlying logic.
- Reusability of Components: If you want to reuse parts of your app in other projects, MVC’s modular structure makes this easier.
- Testing Requirements: MVC supports thorough testing, allowing you to test each component separately for better quality control.
When Not to Use the MVC Design Pattern
Below is when not to use MVC Design Pattern:
- Simple Applications: For small apps with limited functionality, MVC can add unnecessary complexity. A simpler approach may be better.
- Real-Time Applications: MVC may not work well for apps that require immediate updates, like online games or chat apps.
- Tightly Coupled UI and Logic: If the UI and business logic are closely linked, MVC might complicate things further.
- Limited Resources: For small teams or those unfamiliar with MVC, simpler designs can lead to faster development and fewer issues.
Similar Reads
Design Patterns Gamma
Elements of Reusable Object-Oriented Software is a software engineering book describing software design patterns. The book was written by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, with a foreword by Grady Booch. The book is divided into two parts, with the first two chapters expl
6 min read
Memento Design Pattern
The Memento Design Pattern is a behavioral pattern that helps save and restore an object's state without exposing its internal details. It is like a "snapshot" that allows you to roll back changes if something goes wrong. It is widely used in undo-redo functionality in applications like text editors
6 min read
Observer Design Pattern
The Observer Design Pattern is a behavioral design pattern that defines a one-to-many dependency between objects. When one object (the subject) changes state, all its dependents (observers) are notified and updated automatically. Table of Content What is the Observer Design Pattern?Real-world analog
8 min read
Mediator Design Pattern
The Mediator Design Pattern simplifies communication between multiple objects in a system by centralizing their interactions through a mediator. Instead of objects interacting directly, they communicate via a mediator, reducing dependencies and making the system easier to manage. Table of Content Wh
7 min read
Microservices Design Patterns
Microservices Design Patterns explains how to build and manage microservices, which are small, independent services that work together in an application. It introduces different design patterns, or best practices, that help in organizing these services effectively. These patterns cover various aspec
11 min read
SAGA Design Pattern
The SAGA Design Pattern is a pattern used to manage long-running and distributed transactions, particularly in microservices architecture. Unlike traditional monolithic transactions, which require a single, centralized transaction management system, the SAGA pattern breaks down a complex transaction
8 min read
State Design Pattern
The State design pattern is a behavioral software design pattern that allows an object to alter its behavior when its internal state changes. It achieves this by encapsulating the object's behavior within different state objects, and the object itself dynamically switches between these state objects
11 min read
Proxy Design Pattern
The Proxy Design Pattern a structural design pattern is a way to use a placeholder object to control access to another object. Instead of interacting directly with the main object, the client talks to the proxy, which then manages the interaction. This is useful for things like controlling access, d
9 min read
Null Object Design Pattern
The Null Object Design Pattern is a behavioral design pattern that is used to provide a consistent way of handling null or non-existing objects. It is particularly useful in situations where you want to avoid explicit null checks and provide a default behavior for objects that may not exist. Importa
7 min read
Object Pool Design Pattern
The Object Pool Design Pattern is a creational design pattern that manages a pool of reusable objects to minimize the overhead of creating and destroying objects. It maintains a collection of initialized objects and provides mechanisms for clients to efficiently borrow and return objects from the po
9 min read