org.apache.http.annotation.Immutable Maven / Gradle / Ivy
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* ====================================================================
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* .
*
*/
package org.apache.http.annotation;
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* - constructors and methods do not publish references to any internal state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.
*/
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS) // The original version used RUNTIME
public @interface Immutable {
}