Unlock the Power of Java’s compute() Method
When working with HashMaps in Java, you need a way to update values efficiently. That’s where the compute() method comes in – a game-changer for manipulating your data.
Understanding the compute() Syntax
The compute() method takes two essential parameters: key and remappingFunction. The key is the identifier associated with the value you want to update, while the remappingFunction is a BiFunction that calculates the new value.
How compute() Works Its Magic
This method returns the new value linked to the specified key. If no value is associated with the key, it returns null. But here’s the catch: if the remappingFunction returns null, the mapping for the key is removed.
A Real-World Example: Discounts Made Easy
Let’s say you have a HashMap called prices that stores the costs of various items. You want to apply a 10% discount to the price of “Shoes”. Using the compute() method, you can achieve this with a lambda expression:
prices.compute("Shoes", (key, value) -> value - value * 10/100);
This expression reduces the old value of “Shoes” by 10% and returns the updated price. The compute() method then associates this new value with the “Shoes” key.
Simplifying Your Code
According to Java’s official documentation, the HashMap merge() method is a simpler alternative to compute(). If you’re looking for more ways to optimize your code, explore other HashMap methods like computeIfAbsent() and computeIfPresent().