| Consider a switch statement that doesn't handle all possible values and doesn't |
| have a default: |
| |
| ```java |
| enum Colors { RED, GREEN, BLUE } |
| |
| switch (color) { |
| case RED: |
| case GREEN: |
| paint(color); |
| break; |
| } |
| ``` |
| |
| The author's intent isn't clear. There are three possibilities: |
| |
| 1. The default case is known to be impossible. This could be made clear by |
| adding: \ |
| `default: throw new AssertionError(color);` |
| |
| 2. The code intentionally 'falls out' of the switch on the default case, and |
| execution continues below. This could be made clear by adding: \ |
| `default: // fall out` |
| |
| 3. The code has a bug, and the missing cases should have been handled. |
| |
| To avoid this ambiguity, the Google Java Style Guide [requires][style] each |
| switch statement on an enum type to either handle all values of the enum, or |
| have a default statement group. |
| |
| [style]: https://google.github.io/styleguide/javaguide.html#s4.8.4.3-switch-default |
