public long interval() { long tprev = evtime; evtime = System.currentTimeMillis(); return (tprev == 0) ? 0 : (evtime - tprev);
public long interval(long newtime) { long elapsed; if (evtime == 0) { elapsed = 0; } else { elapsed = newtime - evtime; } evtime = newtime; return elapsed;
public long interval() {    long tprev = evtime;    evtime = System.currentTimeMillis();    return (tprev == 0) ? 0 : (evtime - tprev);}