public Quote(Symbol symbol, long timestamp, float price) {
        if (symbol == null) {
            throw new IllegalArgumentException();
        }
        if (timestamp < 0) {
            throw new IllegalArgumentException("Timestamp should be non negative");
        }
        if (price < 0) {
            throw new IllegalArgumentException("Price should be non negative");
        }
        this.symbol = symbol;
        this.timestamp = timestamp;
        this.price = price;
    }