How to Optimize Java Switch Statements with Multiple Cases?

What are the best practices to optimize a Java switch statement with numerous cases?

switch (value) {
    case 1:
        // action for case 1
        break;
    case 2:
        // action for case 2
        break;
    // more cases
    default:
        // action for default
}

Java switch statements can become unwieldy and affect performance when handling many cases. Optimizing these statements can lead to improved code maintainability, performance, and readability. Here are key strategies to refine switch statements effectively.

// Example using Map to optimize switch statement:
Map<Integer, Runnable> actionMap = new HashMap<>();
actionMap.put(1, this::actionForOne);
actionMap.put(2, this::actionForTwo);
// ... Add more actions

// Execute based on value
Runnable action = actionMap.get(value);
if (action != null) {
    action.run();
} else {
    // handle default case
}

Causes

• Large number of cases in switch statement affecting readability.
• Lack of use of enums or constants for case values.
• Redundant code across multiple cases.
• Frequent modifications leading to higher complexity.

Solutions

• Utilize enums instead of constants in switch cases for better type safety and clarity.
• Employ a lookup table or a Map to replace switch statements, especially when dealing with complex logic or numerous cases.
• Consider using polymorphism or strategy patterns to encapsulate behavior instead of relying solely on switch cases.
• Refactor common actions into methods to avoid code duplication within case blocks.
• Use the enhanced switch statement introduced in Java 12 for better syntax and control flow.

Mistake: Directly using switch cases for business logic instead of methods.

Solution: Encapsulate business logic within dedicated methods to enhance readability and maintainability.

Mistake: Neglecting to handle default cases.

Solution: Always implement a default case to manage unexpected input effectively.

Mistake: Duplicating code across multiple case statements.

Solution: Identify commonalities across cases to create a single method that can be invoked where needed.