Transfer Object

The Transfer Object pattern is used when an object with multiple attributes needs to be passed from client to server. A model is a simple POJO class having accessor/mutator methods and is serializable so that it can be transferred over the network. The BusinessManager retrieves data from the db and sends it to the client.

public class StudentModel {
	
	private long id;
	private String firstName;
	private String lastName;
	private LocalDate dob;

	public StudentModel(String firstName, String lastName, LocalDate dob) {
		this.firstName = firstName;
		this.lastName = lastName;
		this.dob = dob;
	}

	public long getId() {
		return id;
	}

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

	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 LocalDate getDob() {
		return dob;
	}

	public void setDob(LocalDate dob) {
		this.dob = dob;
	}

	@Override
	public int hashCode() {
		// code, REQUIRED
	}

	@Override
	public boolean equals(Object obj) {
		// code, REQUIRED
	}
}

public class BusinessManager {
	
	private final Set<StudentModel> students;	// in memory db

	public BusinessManager() {
		
		students = new HashSet<>();
		
		StudentModel student = new StudentModel("Bob", "Brown", LocalDate.of(1950, 8, 20));
		students.add(student);
		
		student = new StudentModel("John", "Smith", LocalDate.of(1962, 2, 11));
		students.add(student);
	}

	public void deleteStudent(StudentModel student) {
		students.remove(student);
		System.out.println("Student " + student.getFirstName() + " " +
				student.getLastName() + " deleted from database.");
	}

	public Set<StudentModel> getAllStudents() {
		return students;
	}

	public void updateStudent(StudentModel student) {
		students.add(student);
		System.out.println("Student " + student.getFirstName() + " " +
				student.getLastName() + " updated.");
	}
}

public class TransferObjectPattern {

	public static void main(String[] args) {

		BusinessManager manager = new BusinessManager();

		// print students
		for(StudentModel student: manager.getAllStudents()) {
			System.out.println(student.getFirstName() + " " + student.getLastName() + ", DOB: " + student.getDob());
		}
	}
}