@Immutable annotation for value classes

[jwgmeligmeyling]

Hi!

I am currently migrating a projeect from jsr305 to java-annotations. One of the annotations I can't really seem to find an equivalent for is @Immutable. A class being @Immutable should not have setters and possibly not even non-final fields.

The original implementation and documentation:

/**
 * The class to which this annotation is applied is immutable. This means that
 * its state cannot be seen to change by callers. Of necessity this means that
 * all public fields are final, and that all public final reference fields refer
 * to other immutable objects, and that methods do not publish references to any
 * internal state which is mutable by implementation even if not by design.
 * Immutable objects may still have internal mutable state for purposes of
 * performance optimization; some state variables may be lazily computed, so
 * long as they are computed from immutable state and that callers cannot tell
 * the difference.
 * <p>
 * Immutable objects are inherently thread-safe; they may be passed between
 * threads or published without synchronization.
 */
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS)
public @interface Immutable {
}