Java MVC pattern

The MVC pattern represents the Model-View-Controller pattern.

As we can see from the name, the MVC pattern involves three parts:

• Model - A model represents an object that carries data. It can also have logic to update the controller if its data changes.

• View - A view represents a visualization of the data contained by the model. Usually it has UI logic.

• Controller - Controllers reference models  and views. It controls the flow of data into model objects and updates views when data changes. It keeps view and model separate.

example

class Employee {
  private String id;
  private String name;

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
}

class EmployeeView {
  public void printEmployeeDetails(String name, String no) {
    System.out.println("Employee: ");
    System.out.println("Name: " + name);
    System.out.println("ID: " + no);
  }
}

class EmployeeController {
  private Employee model;
  private EmployeeView view;

  public EmployeeController(Employee model, EmployeeView view) {
    this.model = model;
    this.view = view;
  }

  public void setEmployeeName(String name) {
    model.setName(name);
  }

  public String getEmployeeName() {
    return model.getName();
  }

  public void setEmployeeId(String rollNo) {
    model.setId(rollNo);
  }

  public String getEmployeeId() {
    return model.getId();
  }

  public void updateView() {
    view.printEmployeeDetails(model.getName(), model.getId());
  }
}

public class Main {
  public static void main(String[] args) {
    Employee model = new Employee();
    model.setName("Tom");
    model.setId("1");
    EmployeeView view = new EmployeeView();

    EmployeeController controller = new EmployeeController(model, view);
    controller.updateView();
    controller.setEmployeeName("New Name");
    controller.updateView();
  }
}

 

The above code produces the following result.