1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.support.annotation;
18
19import java.lang.annotation.ElementType;
20import java.lang.annotation.Retention;
21import java.lang.annotation.RetentionPolicy;
22import java.lang.annotation.Target;
23
24/**
25 * Denotes that the annotated method or field can only be accessed when holding the referenced lock.
26 * <p>
27 * Example:
28 * <pre>
29 * final Object objectLock = new Object();
30 *
31 * {@literal @}GuardedBy("objectLock")
32 * volatile Object object;
33 *
34 * Object getObject() {
35 *     synchronized (objectLock) {
36 *         if (object == null) {
37 *             object = new Object();
38 *         }
39 *     }
40 *     return object;
41 * }</pre>
42 */
43@Target({ ElementType.FIELD, ElementType.METHOD })
44@Retention(RetentionPolicy.CLASS)
45public @interface GuardedBy {
46    String value();
47}
48