Loanable.java

public interface Loanable {
    void borrowCopy(Member member);
    void returnCopy(Member member);
}

public class Movie implements Loanable {

    private final String title;
    private int availableCopies = 1;
    private List<Member> onLoanTo = new ArrayList<>();

    public Movie(String title) {
        this.title = title;
    }

    @Override
    public void borrowCopy(Member member) {
        availableCopies -= 1;
        onLoanTo.add(member);
    }

    @Override
    public void returnCopy(Member member) {
        availableCopies++;
        onLoanTo.remove(member);
    }

    public String getTitle() {
        return title;
    }

    public int getAvailableCopies() {
        return availableCopies;
    }

    public Boolean isOnLoanTo(Member member) {
        return onLoanTo.contains(member);
    }
}

public class LoansView {

    private Member member;
    private Loanable selectedMovie;

    public LoansView(Member member, Loanable selectedMovie) {
        this.member = member;
        this.selectedMovie = selectedMovie;
    }

    public void borrowMovie(){
        selectedMovie.borrowCopy(member);
    }

    public void returnMovie(){
        selectedMovie.returnCopy(member);
    }
}