Immutable.java

/**
 *  Copyright 2005-2016 Red Hat, Inc.
 *
 *  Red Hat licenses this file to you under the Apache License, version
 *  2.0 (the "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License 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 io.fabric8.utils.jcip;
import java.lang.annotation.*;

/*
 * Copyright (c) 2005 Brian Goetz and Tim Peierls
 * Released under the Creative Commons Attribution License
 *   (http://creativecommons.org/licenses/by/2.5)
 * Official home: http://www.jcip.net
 *
 * Any republication or derived work distributed in source code form
 * must include this copyright and license notice.
 */


/**
 * 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
 * <ul>
 * <li> all public fields are final, </li>
 * <li> all public final reference fields refer to other immutable objects, and </li>
 * <li> constructors and methods do not publish references to any internal state
 *      which is potentially mutable by the implementation. </li>
 * </ul>
 * 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.RUNTIME)
public @interface Immutable {
}