1package javax.annotation.concurrent;
2
3import java.lang.annotation.Documented;
4import java.lang.annotation.ElementType;
5import java.lang.annotation.Retention;
6import java.lang.annotation.RetentionPolicy;
7import java.lang.annotation.Target;
8
9/*
10 * Copyright (c) 2005 Brian Goetz
11 * Released under the Creative Commons Attribution License
12 *   (http://creativecommons.org/licenses/by/2.5)
13 * Official home: http://www.jcip.net
14 */
15
16/**
17 * Immutable
18 *
19 * The class to which this annotation is applied is immutable. This means that
20 * its state cannot be seen to change by callers. Of necessity this means that
21 * all public fields are final, and that all public final reference fields refer
22 * to other immutable objects, and that methods do not publish references to any
23 * internal state which is mutable by implementation even if not by design.
24 * Immutable objects may still have internal mutable state for purposes of
25 * performance optimization; some state variables may be lazily computed, so
26 * long as they are computed from immutable state and that callers cannot tell
27 * the difference.
28 *
29 * Immutable objects are inherently thread-safe; they may be passed between
30 * threads or published without synchronization.
31 */
32@Documented
33@Target(ElementType.TYPE)
34@Retention(RetentionPolicy.CLASS)
35public @interface Immutable {
36}
37