com.neko233.toolchain.common.annotation.Immutable Maven / Gradle / Ivy
package com.neko233.toolchain.common.annotation;
import java.lang.annotation.*;
/**
* The presence of this annotation indicates that the author believes the class
* to be immutable and hence inherently thread-safe. An immutable class is one
* where the state of an instance cannot be seen to change. As a result
*
* - All public fields must be {@code final}
* - All public final reference fields are either {@code null} or refer to
* other immutable objects
* - Constructors and methods do not publish references to any potentially
* mutable internal state.
*
* Performance optimization may mean that instances of an immutable class may
* have mutable internal state. The critical point is that callers cannot tell
* the difference. For example {@link String} is an immutable class, despite
* having an internal int that is non-final but used as a cache for
* {@link String#hashCode()}.
*
* Immutable objects are inherently thread-safe; they may be passed between
* threads or published without synchronization.
*
* This annotation is intended for internal use in OSHI as a temporary
* workaround until it is available in {@code jakarta.annotations}.
*/
@Documented
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Immutable {
String tips() default "";
}