/*
* ====================================================================
* 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
* <http://www.apache.org/>.
*
*/
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 field or method to which this annotation is applied can only be accessed
* when holding a particular lock, which may be a built-in (synchronization) lock,
* or may be an explicit java.util.concurrent.Lock.
*
* <p>
* The argument determines which lock guards the annotated field or method:
* </p>
* <ul>
* <li>
* {@code this} : The intrinsic lock of the object in whose class the field is defined.
* </li>
* <li>
* {@code class-name.this} : For inner classes, it may be necessary to disambiguate 'this';
* the <em>class-name.this</em> designation allows you to specify which 'this' reference is intended
* </li>
* <li>
* {@code itself} : For reference fields only; the object to which the field refers.
* </li>
* <li>
* {@code field-name} : The lock object is referenced by the (instance or static) field
* specified by <em>field-name</em>.
* </li>
* <li>
* {@code class-name.field-name} : The lock object is reference by the static field specified
* by <em>class-name.field-name</em>.
* </li>
* <li>
* {@code method-name()} : The lock object is returned by calling the named nil-ary method.
* </li>
* <li>
* {@code class-name.class} : The Class object for the specified class should be used as the lock object.
* </li>
* </ul>
* <p>
* 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.
* </p>
*/
@Documented
@Target({ElementType.FIELD, ElementType.METHOD})
@Retention(RetentionPolicy.CLASS) // The original version used RUNTIME
public @interface GuardedBy {
String value();
}