Common subexpression can be extracted from 'switch'

Reports switch expressions and statements where every branch has a common subexpression, and the switch can be moved inside. This action shortens the code. In many cases, it's reasonable to extract the resulting switch expression to a separate variable or method.

Example:

  switch (value) {
    case 0 -> System.out.println("zero");
    case 1 -> System.out.println("one");
    case 2, 3, 4 -> System.out.println("few");
    default -> System.out.println("many");
  }

After the quick-fix is applied:

  System.out.println(switch (value) {
    case 0 -> "zero";
    case 1 -> "one";
    case 2, 3, 4 -> "few";
    default -> "many";
  });

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

SwitchExpressionCanBePushedDown

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Java | Control flow issues

This inspection is applicable only for enhanced switches with arrow syntax.

This inspection depends on the Java feature ''switch' expressions' which is available since Java 14.

New in 2022.3

Availability

By default bundled with: IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,
Can be installed with plugin: Java, 241.18072

Last modified: 18 June 2024