How to Transform an If-Else Ladder within a For Loop to Functional Style in Java

How can I convert an if-else ladder inside a for loop to a functional programming style in Java?

for (String fruit : fruits) {
    if (fruit.equals("Apple")) {
        System.out.println("This is an Apple!");
    } else if (fruit.equals("Banana")) {
        System.out.println("This is a Banana!");
    } else {
        System.out.println("This is some other fruit!");
    }
}

Converting an if-else ladder within a for loop in Java to functional programming style enhances code readability and maintainability. By leveraging Java Streams and lambda expressions, we can achieve a cleaner, more expressive solution.

Arrays.asList(fruits).stream()
    .map(fruit -> {
        if (fruit.equals("Apple")) {
            return "This is an Apple!";
        } else if (fruit.equals("Banana")) {
            return "This is a Banana!";
        } else {
            return "This is some other fruit!";
        }
    })
    .forEach(System.out::println);

Causes

• If-else ladders can become complex and hard to read as they grow in size.
• Functional programming emphasizes immutability and cleaner code practices.

Solutions

• Use Java Streams to iterate over a collection and apply conditional logic using filter and map methods.
• Utilize lambda expressions to replace the traditional conditional structure with a more declarative approach.

Mistake: Forgetting to handle exceptions or edge cases when using functional programming.

Solution: Ensure to include `Optional` or default values to handle potential nulls or unexpected input.

Mistake: Overcomplicating the stream process with unnecessary intermediate operations.

Solution: Keep the stream operations simple and focused, using `filter` and `map` appropriately.