oshi.annotation.concurrent.Immutable Maven / Gradle / Ivy
/**
* MIT License
*
* Copyright (c) 2010 - 2020 The OSHI Project Contributors: https://github.com/oshi/oshi/graphs/contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package oshi.annotation.concurrent;
import java.lang.annotation.Documented;
/**
* 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* - Constructors and methods do not publish references to any potentially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
public @interface Immutable {
}