1 /* 2 * Copyright (C) 2022 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 com.android.internal.annotations; 18 19 import static java.lang.annotation.ElementType.FIELD; 20 21 import java.lang.annotation.Retention; 22 import java.lang.annotation.RetentionPolicy; 23 import java.lang.annotation.Target; 24 25 /** 26 * Denotes that the annotated field should not be optimized away when 27 * the code is minified at build time. This is typically used 28 * on write-only members that could otherwise be removed except for downstream 29 * weak references that might rely on keep-alive semantics for that field. 30 * <p>Example: 31 * <pre><code> 32 * @KeepForWeakReference 33 * private final Runnable mFooCallback = this::onFoo; 34 * .... 35 * public void registerFooCallbacks(WeakCallbackRegistry registry) { 36 * registry.register(mFooCallback); 37 * } 38 * </code></pre> 39 */ 40 @Retention(RetentionPolicy.CLASS) 41 @Target({FIELD}) 42 public @interface KeepForWeakReference { 43 } 44