Which Design Pattern Cleans Up This If-Else Mess?

In real-world coding, we often encounter business scenarios where different input conditions trigger different logic, leading to lengthy if-else chains.

The article presents a typical example: a discount calculation that varies by user type.

if (userType.equals("common")) {
    discount = 0.9;
    totalAmount = discount * totalQuantity;
} else if (userType.equals("junior")) {
    discount = 0.8;
    totalAmount = discount * totalQuantity;
} else if (userType.equals("senior")) {
    discount = 0.6;
    totalAmount = discount * totalQuantity;
    addCoupon();
} else if (userType.equals("super")) {
    discount = 0.5;
    totalAmount = discount * totalQuantity;
    sendGift();
}

Each branch sets a discount multiplier, computes the total amount, and for senior and super users also invokes additional behaviors (addCoupon, sendGift). The author then poses the question: what design pattern should be used to refactor this code and make it more elegant?

The provided excerpt does not include the answer or a detailed discussion of specific patterns; it ends with recommended reading links to other articles.