| package checkers.quals; |
| |
| import static java.lang.annotation.ElementType.FIELD; |
| import java.lang.annotation.*; |
| |
| /** |
| * Declares that the field may not be accessed if the receiver is of the |
| * specified qualifier type (or any supertype). |
| * |
| * This property is verified by the checker that type-checks the {@code |
| * when} element value qualifier. |
| * |
| * <p><b>Example</b> |
| * Consider a class, {@code Table}, with a locking field, {@code lock}. The |
| * lock is used when a {@code Table} instance is shared across threads. When |
| * running in a local thread, the {@code lock} field ought not to be used. |
| * |
| * You can declare this behavior in the following way: |
| * |
| * <pre><code> |
| * class Table { |
| * private @Unused(when=LocalToThread.class) final Lock lock; |
| * ... |
| * } |
| * </code></pre> |
| * |
| * The checker for {@code @LocalToThread} would issue an error for the following code: |
| * |
| * <pre> @LocalToThread Table table = ...; |
| * ... table.lock ...; |
| * </pre> |
| * |
| */ |
| @Documented |
| @Retention(RetentionPolicy.RUNTIME) |
| @Target({FIELD}) |
| public @interface Unused { |
| /** |
| * The field that is annotated with @Unused may not be accessed via a |
| * receiver that is annotated with the "when" annotation. |
| */ |
| Class<? extends Annotation> when(); |
| } |