A simple wrapper around a Swing `Timer` that provides `Duration` based animation that also provides pause/resume functionality

Animator.java

public class Animator {

    private Instant startTime;
    private Duration totalRunTime = Duration.ZERO;

    private Duration runTime;

    private Timer timer;

    private List<Ticker> tickers;

    public Animator(Duration duration) {
        tickers = new ArrayList<>(25);
        this.runTime = duration;
        timer = new Timer(5, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Duration runningTime = getDuration();
                if (runningTime.compareTo(getRunTime()) > 0) {
                    stop();
                    reset();
                    runningTime = getRunTime();
                }
                double progress = runningTime.toMillis() / (double) runTime.toMillis();
                if (progress >= 1.0) {
                    progress = 1.0d;
                    stop();
                    reset();
                }
                for (Ticker ticker : tickers) {
                    ticker.tick(progress);
                }
            }
        });
    }

    public void addTicker(Ticker ticker) {
        tickers.add(ticker);
    }

    public void removeTicker(Ticker ticker) {
        tickers.remove(ticker);
    }

    public Duration getRunTime() {
        return runTime;
    }

    public void start() {
        startTime = Instant.now();
        timer.start();
    }

    public void stop() {
        timer.stop();
        if (startTime != null) {
            Duration runTime = Duration.between(startTime, Instant.now());
            totalRunTime = totalRunTime.plus(runTime);
        }
        startTime = null;
    }

    public void pause() {
        stop();
    }

    public void resume() {
        start();
    }

    public void reset() {
        stop();
        totalRunTime = Duration.ZERO;
    }

    public boolean isRunning() {
        return startTime != null;
    }

    public Duration getDuration() {
        Duration currentDuration = Duration.ZERO;
        currentDuration = currentDuration.plus(totalRunTime);
        if (isRunning()) {
            Duration runTime = Duration.between(startTime, Instant.now());
            currentDuration = currentDuration.plus(runTime);
        }
        return currentDuration;
    }
}

Ticker.java

public interface Ticker {
    public void tick(double progress);
}

It might be used something like...

Animator animator = new Animator(Duration.ofSeconds(5));
animator.addTicker(new Ticker() {
    @Override
    public void tick(double progress) {
        // Perform required animation
    }
});
animator.start();