Quero saber como definir o horário da notificação. Quero definir uma notificação a cada cinco minutos, então me ajude a fazer isso.

public class FirstActivity extends Activity
{
    private static final int HELLO_ID = 1;
    //public static final int FLAG_AUTO_CANCEL = 0;`enter code here`
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.firstactivity);

        String ns = Context.NOTIFICATION_SERVICE;
        NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);

        int icon = R.drawable.icon;
        CharSequence tickerText = "Hello";
        long when = System.currentTimeMillis();

        Notification notification = new Notification(icon, tickerText, when);

        RemoteViews contentView = new RemoteViews(getPackageName(), R.layout.statusbarnotification);
        contentView.setImageViewResource(R.id.image, R.drawable.icon);
        contentView.setTextViewText(R.id.text, "Hello, this message is in a custom expanded view");
        notification.contentView = contentView;
        notification.flags = Notification.DEFAULT_LIGHTS | Notification.FLAG_AUTO_CANCEL;
        Intent notificationIntent = new Intent(getApplicationContext(), SecondActivity.class);
        //PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
        notification.contentIntent = contentIntent;
        mNotificationManager.notify(HELLO_ID, notification);
    }

}