xref: /aosp_15_r20/external/dagger2/java/dagger/hilt/codegen/OriginatingElement.java (revision f585d8a307d0621d6060bd7e80091fdcbf94fe27)
1*f585d8a3SJacky Wang /*
2*f585d8a3SJacky Wang  * Copyright (C) 2020 The Dagger Authors.
3*f585d8a3SJacky Wang  *
4*f585d8a3SJacky Wang  * Licensed under the Apache License, Version 2.0 (the "License");
5*f585d8a3SJacky Wang  * you may not use this file except in compliance with the License.
6*f585d8a3SJacky Wang  * You may obtain a copy of the License at
7*f585d8a3SJacky Wang  *
8*f585d8a3SJacky Wang  * http://www.apache.org/licenses/LICENSE-2.0
9*f585d8a3SJacky Wang  *
10*f585d8a3SJacky Wang  * Unless required by applicable law or agreed to in writing, software
11*f585d8a3SJacky Wang  * distributed under the License is distributed on an "AS IS" BASIS,
12*f585d8a3SJacky Wang  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13*f585d8a3SJacky Wang  * See the License for the specific language governing permissions and
14*f585d8a3SJacky Wang  * limitations under the License.
15*f585d8a3SJacky Wang  */
16*f585d8a3SJacky Wang 
17*f585d8a3SJacky Wang package dagger.hilt.codegen;
18*f585d8a3SJacky Wang 
19*f585d8a3SJacky Wang /**
20*f585d8a3SJacky Wang  * An annotation used to specify the originating element that triggered the code generation of a
21*f585d8a3SJacky Wang  * type. This annotation should only be used on generated code and is meant to be used by code
22*f585d8a3SJacky Wang  * generators that generate Hilt modules, entry points, etc. Failure to use this annotation may mean
23*f585d8a3SJacky Wang  * improper test isolation for generated classes.
24*f585d8a3SJacky Wang  *
25*f585d8a3SJacky Wang  * <p>This annotation should be used on any generated top-level class that either contains generated
26*f585d8a3SJacky Wang  * modules (or entry points) or contains annotations that will generate modules (or entry points).
27*f585d8a3SJacky Wang  *
28*f585d8a3SJacky Wang  * <p>Example: Suppose we have the following use of an annotation, {@code MyAnnotation}.
29*f585d8a3SJacky Wang  *
30*f585d8a3SJacky Wang  * <pre><code>
31*f585d8a3SJacky Wang  *   class Outer {
32*f585d8a3SJacky Wang  *     static class Inner {
33*f585d8a3SJacky Wang  *       {@literal @}MyAnnotation Foo foo;
34*f585d8a3SJacky Wang  *     }
35*f585d8a3SJacky Wang  *   }
36*f585d8a3SJacky Wang  * </code></pre>
37*f585d8a3SJacky Wang  *
38*f585d8a3SJacky Wang  * <p>If {@code MyAnnotation} generates an entry point, it should be annotated as follows:
39*f585d8a3SJacky Wang  *
40*f585d8a3SJacky Wang  * <pre><code>
41*f585d8a3SJacky Wang  *   {@literal @}OriginatingElement(topLevelClass = Outer.class)
42*f585d8a3SJacky Wang  *   {@literal @}EntryPoint
43*f585d8a3SJacky Wang  *   {@literal @}InstallIn(SingletonComponent.class) {
44*f585d8a3SJacky Wang  *       ...
45*f585d8a3SJacky Wang  *   }
46*f585d8a3SJacky Wang  * </code></pre>
47*f585d8a3SJacky Wang  */
48*f585d8a3SJacky Wang // TODO(bcorso): Consider just advising/enforcing that all top-level classes use this annotation.
49*f585d8a3SJacky Wang public @interface OriginatingElement {
50*f585d8a3SJacky Wang   /** Returns the top-level class enclosing the originating element. */
topLevelClass()51*f585d8a3SJacky Wang   Class<?> topLevelClass();
52*f585d8a3SJacky Wang }
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