public class Student extends Person implements NamedEntity {
	private String matrikelNo;

	public Student(String matrikelNo) {
		this.matrikelNo = matrikelNo;
	} //constructor

	public String getMatrikelNo() {
		return matrikelNo;
	} //getMatrikelNo;

	public boolean setMatrikelNo(String matrikelNo) {
		if (matrikelNo.compareTo("")==0) {
			this.matrikelNo = matrikelNo;
			return true;
		} else
			return false;
	} //setMatrikelNo()

	public String getName() {
		return name;
	} //getName()

	public boolean setName(String newName) {
		if (newName.compareTo("")!=0) {
			name = newName;
			return true;
		} else
			return false;
	} //setName()

	public String toString() {
		return ("Name: "+this.getName()+"\nMatrikelnummer: "+this.getMatrikelNo() );
	} //toString()

	public static void main(String[] args) {
		Student mario = new Student("0793022");
		System.out.println( mario.getMatrikelNo() );
		System.out.println("mario.toString() returns:\n"+mario.toString() );
		mario.setName("Mario Jeckle");
		System.out.println("mario.toString() returns:\n"+mario.toString() );
	} //main()
} //class Student

class Person {
	String	name;
} //class Person

interface NamedEntity {
	String getName();
	boolean setName(String newName);
} //interface NamedEntity