DAO Pattern

Employee.java

public class Employee {

	private String firstName, lastName;
	private String designation;
	private String employeeCode;
	public Employee(String employeeCode, String firstName, String lastName, String designation){
		this.employeeCode=employeeCode;
		this.firstName=firstName;
		this.lastName=lastName;
		this.designation=designation;
	}
	public String getFirstName() {
		return firstName;
	}
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	public String getLastName() {
		return lastName;
	}
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
	public String getDesignation() {
		return designation;
	}
	public void setDesignation(String designation) {
		this.designation = designation;
	}
	public String getEmployeeCode() {
		return employeeCode;
	}
	public void setEmployeeCode(String employeeCode) {
		this.employeeCode = employeeCode;
	}
	
	public String toString(){
		return "[EmployeeCode : "+employeeCode+", LastName : "+lastName+", FirstName : "+firstName+", Designation : "+designation+"]";
	}
}

EmployeeDAO.java

import java.util.HashMap;
import java.util.Map;

public class EmployeeDAO {
	
	protected Map employeeMap;
	
	public EmployeeDAO(){
		employeeMap = new HashMap();
	}

	public Employee getEmployee(String employeeCode){
		return employeeMap.get(employeeCode);
	}
	
	public void addEmployee(String employeeCode, String firstName, String lastName, String designation){
		employeeMap.put(employeeCode, new Employee(employeeCode,firstName,lastName,designation));
	}
	
	public void updateEmployee(Employee employee){
		employeeMap.put(employee.getEmployeeCode(), employee);
	}
	
}

DAOPatternDemo.java

public class DAOPatternDemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		//update database
		EmployeeDAO dao = new EmployeeDAO();
		dao.addEmployee("1", "Tina", "Roz", "PM");
		dao.addEmployee("2", "Mina", "Koze", "Lead");
		dao.addEmployee("3", "Ina", "Arase", "Developer");
		dao.addEmployee("4", "Hina", "Mase", "Tester");
		
		//get employee with code 4
		System.out.println("EmployeeCode :4 "+dao.getEmployee("4"));
		
		//update Designation of Employee3
		Employee employee3 = dao.getEmployee("3");
		employee3.setDesignation("Sr. Developer");
		dao.updateEmployee(employee3);
		System.out.println("After update Employee : 3 "+ dao.getEmployee("3"));
		
	}

}

Output