Blog :: New Narayana release and Spring Boot quickstart :: Buy operation

buy.java

@PutMapping("/portfolio/{username}/{symbol}")
@Transactional
public void buy(@PathVariable String username, @PathVariable String symbol, @RequestParam("amount") int amount) {
    User user = getUser(username);
    Share share = getShare(symbol);
    PortfolioEntry portfolioEntry = getOrCreatePortfolioEntry(user, share); // Get user's portfolio entry or create a new one

    updateBudget(user, -1 * amount * share.getPrice()); // Decrease user's budget
    updateSharesAmount(share, -1 * amount); // Decrease shares amount available for sale
    updatePortfolioEntry(portfolioEntry, amount); // Increase shares amount owned by the user
    sendUpdate(String.format("'%s' just bought %d shares of '%s' for the amount of %d", username, amount, symbol,
            amount * share.getPrice()));
}