homework/OrderValidator.java

public class OrderValidator {
    private static final double MIN_ORDER_AMOUNT = 0.01;
    private static final double MAX_ORDER_AMOUNT = 1000000.0;

    /**
     * 验证订单是否有效
     * @param order 要验证的订单
     * @return 如果订单有效则返回true，否则返回false
     */
    public boolean validateOrder(Order order) {
        if (order == null) {
            return false;
        }

        // 验证订单ID
        if (order.getOrderId() == null || order.getOrderId().trim().isEmpty()) {
            return false;
        }

        // 验证订单金额
        double amount = order.getAmount();
        if (amount < MIN_ORDER_AMOUNT || amount > MAX_ORDER_AMOUNT) {
            return false;
        }

        // 验证客户名称
        if (order.getCustomerName() == null || order.getCustomerName().trim().isEmpty()) {
            return false;
        }

        return true;
    }

    /**
     * 获取订单验证失败的具体原因
     * @param order 要验证的订单
     * @return 验证失败的原因，如果订单有效则返回null
     */
    public String getValidationError(Order order) {
        if (order == null) {
            return "订单对象为空";
        }

        if (order.getOrderId() == null || order.getOrderId().trim().isEmpty()) {
            return "订单ID不能为空";
        }

        double amount = order.getAmount();
        if (amount < MIN_ORDER_AMOUNT) {
            return "订单金额不能小于最小金额";
        }
        if (amount > MAX_ORDER_AMOUNT) {
            return "订单金额不能超过最大金额";
        }

        if (order.getCustomerName() == null || order.getCustomerName().trim().isEmpty()) {
            return "客户名称不能为空";
        }

        return null; // 订单有效
    }
}