1 /* 2 * Copyright (C) 2023 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 package android.annotation; 17 18 import static java.lang.annotation.ElementType.ANNOTATION_TYPE; 19 import static java.lang.annotation.ElementType.CONSTRUCTOR; 20 import static java.lang.annotation.ElementType.FIELD; 21 import static java.lang.annotation.ElementType.METHOD; 22 import static java.lang.annotation.ElementType.TYPE; 23 24 import java.lang.annotation.Retention; 25 import java.lang.annotation.RetentionPolicy; 26 import java.lang.annotation.Target; 27 28 /** 29 * Indicates an API is part of a feature that is guarded by an aconfig flag, and only available if 30 * the flag is enabled. 31 * <p> 32 * Unless the API has been finalized and has become part of the SDK, callers of the annotated API 33 * must check that the flag is enabled before making any assumptions about the existence of the API. 34 * <p> 35 * Example: 36 * <code><pre> 37 * import com.example.foobar.Flags; 38 * 39 * @FlaggedApi(Flags.FLAG_FOOBAR) 40 * public void foobar() { ... } 41 * </pre></code> 42 * Usage example: 43 * <code><pre> 44 * public void codeThatUsesFoobarApi() { 45 * if (Flags.foobar()) { 46 * foobar(); 47 * } else { 48 * // gracefully handle absence of the foobar API. 49 * } 50 * } 51 * </pre></code> 52 * @hide 53 */ 54 @Target({TYPE, METHOD, CONSTRUCTOR, FIELD, ANNOTATION_TYPE}) 55 @Retention(RetentionPolicy.CLASS) 56 public @interface FlaggedApi { 57 /** 58 * The aconfig flag used to guard the feature this API is part of. Use the aconfig 59 * auto-generated constant to refer to the flag, e.g. @FlaggedApi(Flags.FLAG_FOOBAR). 60 */ value()61 String value(); 62 } 63