OnlineStatus.java

public class OnlineStatus {
    public enum States {Unknown, Online}

    private int onlineThresholdHrs;

    public void setOnlineThresholdHrs(int hours) {
        this.onlineThresholdHrs = hours;
    }

    public States getStatus(Date lastOnline, Calendar calendar) {
        int currentHour = calendar.get(Calendar.HOUR_OF_DAY);
        calendar.set(
                Calendar.HOUR_OF_DAY,
                currentHour + onlineThresholdHrs);

        Date onlineThreshold = calendar.getTime();
        if (lastOnline.before(onlineThreshold)) {
            return States.Online;
        } else {
            return States.Unknown;
        }
    }
}