001/*
002 * Copyright 2017 The Error Prone Authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package com.google.errorprone.annotations;
017
018import static java.lang.annotation.ElementType.METHOD;
019import static java.lang.annotation.RetentionPolicy.SOURCE;
020
021import java.lang.annotation.Documented;
022import java.lang.annotation.Retention;
023import java.lang.annotation.Target;
024
025/**
026 * Indicates that any concrete method that overrides the annotated method, directly or indirectly,
027 * must invoke {@code super.theAnnotatedMethod(...)} at some point. This does not necessarily
028 * require an <i>unconditional</i> call; any matching call appearing directly within the method body
029 * (not inside an intervening class or lambda expression) is acceptable.
030 *
031 * <p>If the overriding method is itself overridable, applying this annotation to that method is
032 * technically redundant, but may be helpful to readers.
033 *
034 * <p><b>Preferred:</b> usually, a better solution is to make the method {@code final}, and have its
035 * implementation delegate to a second concrete method which <i>is</i> overridable (or to a function
036 * object which subclasses can specify). "Mandatory" statements remain in the final method while
037 * "optional" code moves out. This is the only way to make sure the statements will be executed
038 * unconditionally.
039 */
040@Documented
041@Target(METHOD)
042@Retention(SOURCE)
043public @interface OverridingMethodsMustInvokeSuper {}