1 /* 2 * Copyright (C) 2020 The Dagger Authors. 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 dagger.hilt.codegen; 18 19 /** 20 * An annotation used to specify the originating element that triggered the code generation of a 21 * type. This annotation should only be used on generated code and is meant to be used by code 22 * generators that generate Hilt modules, entry points, etc. Failure to use this annotation may mean 23 * improper test isolation for generated classes. 24 * 25 * <p>This annotation should be used on any generated top-level class that either contains generated 26 * modules (or entry points) or contains annotations that will generate modules (or entry points). 27 * 28 * <p>Example: Suppose we have the following use of an annotation, {@code MyAnnotation}. 29 * 30 * <pre><code> 31 * class Outer { 32 * static class Inner { 33 * {@literal @}MyAnnotation Foo foo; 34 * } 35 * } 36 * </code></pre> 37 * 38 * <p>If {@code MyAnnotation} generates an entry point, it should be annotated as follows: 39 * 40 * <pre><code> 41 * {@literal @}OriginatingElement(topLevelClass = Outer.class) 42 * {@literal @}EntryPoint 43 * {@literal @}InstallIn(SingletonComponent.class) { 44 * ... 45 * } 46 * </code></pre> 47 */ 48 // TODO(bcorso): Consider just advising/enforcing that all top-level classes use this annotation. 49 public @interface OriginatingElement { 50 /** Returns the top-level class enclosing the originating element. */ topLevelClass()51 Class<?> topLevelClass(); 52 } 53