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 17 package androidx.annotation; 18 19 import java.lang.annotation.ElementType; 20 import java.lang.annotation.Retention; 21 import java.lang.annotation.RetentionPolicy; 22 import 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) 45 public @interface GuardedBy { 46 String value(); 47 } 48
