Forelesningslysark om arv

public class InvalidNameException extends IllegalArgumentException {
    private Person person;
    private String name;
    
    public InvalidNameException(Person person, String name) {
        this.person = person;
        this.name = name;
    }
    
    public Person getPerson() {
        return person;
    }
    public String getName() {
        return name;
    }
    @Override
    public String getMessage() {
        return "Du prøvde å sette navnet til " + name + ", men det er ugyldig for " + person;
    }
}

public class Person {
    
    private String name;
    public Person(String name) {
        this.name = name;
    }
    @Override
    public String toString() {
        return "[Person " + name + " (" + super.toString() + ")]";
    }
    
    public String getName() {
        return name;
    }
    private String legalCharacters = "QWERTYUIOPÅASDFGHJKLØÆZXCVBNM";
    
    public void setName(String name) {
        for (int i = 0; i < name.length(); i++) {
            char c = Character.toUpperCase(name.charAt(i));
            if (legalCharacters.indexOf(c) < 0) {
                throw new InvalidNameException(this, name);
            }
        }
        this.name = name;
    }
    
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Person && ((Person) obj).name.equals(this.name)) {
            return true;
        }
        return false;
    }
    
    public static void main(String[] args) {
        Person person1 = new Person("Hallvard");
        Person person2 = new Person("Hallvard");
        Collection<Person> personer = Arrays.asList(person1, person2);
        System.out.println(person1 == person2);
        System.out.println(person1.equals(person2));
        System.out.println(personer.contains(new Person("Hallvard")));
        person1.setName("ruy389weyfsuid");
    }
}

public class Bok {
    private String title;
    
    public Bok(String title) {
        this.title = title;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    @Override
    public String toString() {
        return "Bok [title=" + title + "]";
    }
    
}

public class Ordbok extends Bok {
    int antallOrd;
    public Ordbok(String title, int antallOrd) {
        super(title);
        this.antallOrd = antallOrd;
    }
    @Override
    public String toString() {
        return "Ordbok [antallOrd=" + antallOrd + ", title=" + getTitle() + "]";
    }
}

public class Tegneseriealbum extends Bok {
    int antallStriper;
    
    public Tegneseriealbum(String title, int antallStriper) {
        super(title);
        this.antallStriper = antallStriper;
    }
}

public class Bibliotek {
    private Bok bok;
    private Ordbok nynorsk;
    private Tegneseriealbum pondus;
    
    public void init() {
        bok = new Bok();
        bok.title = "Sult";
        nynorsk = new Ordbok();
        nynorsk.title = "Nynorsk ordbok";
        nynorsk.antallOrd = 12345;
        pondus = new Tegneseriealbum();
        pondus.title = "Flat firer";
        pondus.antallStriper = 128;
    }
    
    public void run() {
        Bok bok1 = nynorsk;
        Bok bok2 = pondus;
        Ordbok ordbok1 = (Ordbok) bok2;
    }
    
    public static void main(String[] args) {
        Bibliotek program = new Bibliotek();
        program.init();
        program.run();
    }
}

public class Bok {
    private String title;
    
    public Bok(String title) {
        setTitle(title);
    }
    public String getTitle() {
        return title;
    }
    protected boolean isValidTitle(String title) {
        return title.indexOf(' ') < 0;
    }
    
    public void setTitle(String title) {
        if (! isValidTitle(title)) {
            throw new IllegalArgumentException("Ikke gyldig!");
        }
        this.title = title;
    }
    @Override
    public String toString() {
        return "Bok [title=" + title + "]";
    }
    
}

public class Ordbok extends Bok {
    int antallOrd;
    public Ordbok(String title, int antallOrd) {
        super(title);
        this.antallOrd = antallOrd;
    }
    
    @Override
    public String toString() {
        return "Ordbok [antallOrd=" + antallOrd + ", title=" + getTitle() + "]";
    }
    @Override
    protected boolean isValidTitle(String title) {
        return super.isValidTitle(title) &&
                title.endsWith("ordbok");
    }
}

public class Tegneseriealbum extends Bok {
    int antallStriper;
    
    public Tegneseriealbum(String title, int antallStriper) {
        super(title);
        this.antallStriper = antallStriper;
    }
}

public class Bibliotek {
    private Bok bok;
    private Ordbok nynorsk;
    private Tegneseriealbum pondus;
    
    public void init() {
        bok = new Bok("Sult");
        nynorsk = new Ordbok("Nynorsk ordbok", 12345);
        pondus = new Tegneseriealbum("Flat firer", 128);
    }
    
    public void run() {
        Bok bok1 = nynorsk;
        Bok bok2 = pondus;
        if (bok1 instanceof Ordbok) {
            ((Ordbok) bok1).antallOrd = 10;
        }
    }
    
    public static void main(String[] args) {
        Bibliotek program = new Bibliotek();
        program.init();
        program.run();
    }
}