Switch Statements

We use switch statements to execute different parts of code dependant on our observed value. Switch statements are a great way to make multiple choice conditionals easier to read, the same effect can be achieved by an if statement however good quality code needs to be readable as well as functional.

String role = "admin";
switch (role){
  case "admin":
    System.out.println("Congrats, you are an admin!");
    break;
  case "moderator":
    System.out.println("Moderate away!");
    break;
  default:
    System.out.println("You're a guest");
}

Case, Break and Default

Case

A case in a switch statement is similar to an if statement, but it functions by comparing a variable (or expression) against a set of predefined constant values. We use the switch statement to evaluate a variable that may have multiple possible values, and then the case checks for specific values that are important to execute the corresponding code. Each case represents a fixed, static value that the expression is compared against. The case labels themselves are rigid in that they can only be set to constant values and cannot be variables, expressions, or dynamic values (such as the result of a function call). This means the values within the case statements must be constant literals or enumerated types.

Break

In Java once a case is matched the preceding code block will execute, It is important to note that each code block will require a break; in order for the program to exit the switch statement. Without a break; the program will continue executing the next case blocks code - this practice is called a fall-through and may be intentional in some cases.

Default

Providing a default case in a switch statement is considered good practice. It ensures that the program will execute a code block when none of the case labels match the value of the switch expression. This provides a fallback action, which is particularly useful for handling unexpected or invalid values.

The default case is typically placed at the bottom of the switch block, as it serves as the “catch-all” for any unmatched values.