Person.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package relation;

/**
 *
 * @author fonsan
 */
public class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    
    public void printInfo() {
        System.out.println(name);
        System.out.println(age);
    }
    
}

Relation.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package relation;

/**
 *
 * @author fonsan
 */
public class Relation {
    private Person person1;
    private Person person2;
    private String rel;
    
    private static String [] VALID_RELATIONS = {"father", "mother", "sister", "brother", "cousin", "unknown"};

    public Relation(Person person1, Person person2, String rel) {
        this.person1 = person1;
        this.person2 = person2;
        setRel(rel);
    }

    public Person getPerson1() {
        return person1;
    }

    public void setPerson1(Person person1) {
        this.person1 = person1;
    }

    public Person getPerson2() {
        return person2;
    }

    public void setPerson2(Person person2) {
        this.person2 = person2;
    }

    public String getRel() {
        return rel;
    }

    public void setRel(String rel) {
        boolean foundRelation = false;
        for (int i = 0; i < VALID_RELATIONS.length; i++) {
            String relation = VALID_RELATIONS[i];
            if (rel.equals(relation)) {
                foundRelation = true;
                break;
            }
        }
        if (!foundRelation) {
            rel = "unknown";
        }
        this.rel = rel;
    }
    
    public void printInfo() {
        person1.printInfo();
        person2.printInfo();
        System.out.println("Relation: " + rel);
    }
    
    

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Person p1 = new Person("Erik", 22);
        Person p2 = new Person("Ylva", 22);
        Relation r = new Relation(p1, p2, "sister");
        r.printInfo();
    }
}