How do you implement a switch expression in Java 17?

Table of Contents

• Introduction
• Features of Switch Expressions in Java 17
  • 1. Returning Values with **yield**
    • Example:
  • 2. Simplifying Control Flow
    • Example:
• Pattern Matching with Switch Expressions
  • Example with Pattern Matching:
• Practical Example: Using Switch Expressions in Java 17
• Conclusion

Introduction

Java 17 introduced enhancements to the switch statement, allowing it to be used as an expression. This enables the switch to return values, eliminating the need for verbose code. It also supports pattern matching and concise case labels. In this guide, we’ll explore how to implement a switch expression in Java 17 with practical examples.

Features of Switch Expressions in Java 17

1. Returning Values with **yield**

The new switch expression can return values using the yield keyword. This makes it easier to assign results directly from switch, improving code readability and maintainability.

Example:

In this example, the switch expression returns the day name directly based on the dayOfWeek value.

2. Simplifying Control Flow

You can also use block expressions to return values in more complex scenarios. Block expressions allow for multi-line logic inside a case, improving control flow when more processing is needed.

Example:

In this example, we use block expressions to perform actions before yielding a result from the switch expression.

Pattern Matching with Switch Expressions

Java 17 allows pattern matching within switch expressions. This is especially useful when dealing with objects of different types, making the code more concise and easier to understand.

Example with Pattern Matching:

Here, the switch expression checks the type of obj and uses pattern matching to perform different actions based on whether the object is an Integer or String.

Practical Example: Using Switch Expressions in Java 17

Let’s implement a simple application that returns different messages based on the user’s role using a switch expression.

In this example, the switch expression simplifies the logic for handling different roles and returns the appropriate message.

Conclusion

The enhanced switch expressions in Java 17 provide a more powerful and flexible way to handle control flow, allowing for cleaner and more concise code. By using yield to return values, pattern matching for object types, and multi-line block expressions, Java developers can write more efficient and readable code. The switch expression is a valuable addition to the language, especially for scenarios that require evaluating multiple conditions and returning results based on those conditions.