Relevant parts of the trading engine

TradingEngine-run.java

public void run() {
    while (running) {
        prepareMarket();
 
        List<Sale> sales = market.trade();
        LOGGER.info("trading completed");
 
        noteMarketPricesAndVolumes(sales);
 
        persistSale(sales);
        LOGGER.info("persisting completed, notifying involved parties...");
        sales.stream().forEach(sale -> {
            if (sale.getBuyer().listener != null)
                sale.getBuyer().listener.onEvent(EventType.PURCHASE, sale);
            if (sale.getSeller().listener != null)
                sale.getSeller().listener.onEvent(EventType.SALE, sale);
        });
        ...
        try {
            Thread.sleep(delay);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}