Profile.java

@PreferenceEntity(name = "UserProfile")
public class Profile {
    protected final boolean login = false;
    @KeyName(name = "nickname") protected final String userNickName = null;
    @KeyName(name = "visits") protected final int visitCount = 1;

    @KeyName(name = "userPet")
    @TypeConverter(converter = PetConverter.class)
    protected Pet userPetInfo;

    @PreferenceFunction(keyname = "nickname")
    public String putUserNickFunction(String nickname) {
        return "Hello, " + nickname;
    }

    @PreferenceFunction(keyname = "nickname")
    public String getUserNickFunction(String nickname) {
        return nickname + "!!!";
    }

    @PreferenceFunction(keyname = "visits")
    public int putVisitCountFunction(int count) {
        return ++count;
    }
}