Feature/Optional time supplier

[TuxedoFish]

Background

When developing locally my clock gets out of sync pretty fast and it was getting unwieldly to develop. I forked and used this locally to get around my problem. I thought it might be of use to other people as well.

Solution

Add a TimeSupplier class which can be passed a custom long supplier which can be used to adjust the time.

Potential usage

public class BinanceRestAdapter implements VenueAdapter {
    private final SpotClient client;

    public BinanceRestAdapter(String baseUrl, String apiKey, String privateKey, ObjectMapper objectMapper, List<String> tradingCoins) {
        client = new SpotClientImpl(apiKey, privateKey, baseUrl);
        client.setTimeSupplier(SysTime.INSTANCE::currentTimeMillis);
        syncTime();
    }

    ...

    private void syncTime() {
        String timeResult = client.createMarket().time();
        Long serverTimerTime = Long.valueOf(timeResult.substring(14, timeResult.length() - 1));
        Long clientTime = System.currentTimeMillis();
        long delta = clientTime - serverTimerTime;
        SysTime.INSTANCE.setDelta(-delta);
        Long updatedTime = SysTime.INSTANCE.currentTimeMillis();
        LOG.info(String.format("Updating @ local time %s | external time %s (%s ms) | new time delta = %s", clientTime, serverTimerTime, delta, updatedTime - serverTimerTime));
    }
}

With a class something like this

public class SysTime {
    public static SysTime INSTANCE = new SysTime();
    private long delta;

    public long currentTimeMillis() {
        return System.currentTimeMillis() + delta;
    }

    public void setDelta(long delta) {
        this.delta = delta;
    }
}