software.amazon.awssdk.annotations.Immutable Maven / Gradle / Ivy
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package software.amazon.awssdk.annotations;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* The class to which this annotation is applied is immutable. This means that
* its state cannot be seen to change by callers, which implies that
*
* - all public fields are final,
* - all public final reference fields refer to other immutable objects, and
* - constructors and methods do not publish references to any internal state
* which is potentially mutable by the implementation.
*
* 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.
*
* Immutable objects are inherently thread-safe; they may be passed between threads or
* published without synchronization.
*
* Based on code developed by Brian Goetz and Tim Peierls and concepts
* published in 'Java Concurrency in Practice' by Brian Goetz, Tim Peierls,
* Joshua Bloch, Joseph Bowbeer, David Holmes and Doug Lea.
*
* @see Mutable
*/
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS) // The original version used RUNTIME
@SdkProtectedApi
public @interface Immutable {
}