com.google.errorprone.annotations.DoNotCall Maven / Gradle / Ivy
/*
* Copyright 2017 The Error Prone Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.errorprone.annotations;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.CLASS;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.util.List;
/**
* Indicates that the annotated method should not be called under any normal circumstances, yet is
* either impossible to remove, or should not ever be removed. Example:
*
* {@code
* public class ImmutableList implements List {
* @DoNotCall("guaranteed to throw an exception")
* @Override public add(E e) {
* throw new UnsupportedOperationException();
* }
* }
* }
*
* By the demands of the {@code List} interface, this method can never be removed. However, since it
* should always throw an exception, there can be no valid reason to call it except in the rarest of
* circumstances. Although this information can only benefit users who have a reference of type
* {@code ImmutableList} (not {@link List}), it's a good start.
*
* If the typical caller's best remedy is to "inline" the method, {@link InlineMe} is probably a
* better option; read there for more information. Using both annotations together is probably
* unnecessary.
*
*
Note on testing: A {@code @DoNotCall} method should still have unit tests.
*
*
{@code @DoNotCall} and deprecation
*
* Deprecation may feel inappropriate or misleading in cases where there is no intention to ever
* remove the method. It might create the impression of a "blemish" on your API; something that
* should be fixed. Moreover, it's generally hard to enforce deprecation warnings as strongly as a
* {@code @DoNotCall} violation should be.
*
*
But, when choosing the {@code @DoNotCall} option, consider adding {@link Deprecated} as well
* anyway, so that any tools that don't support {@code @DoNotCall} can still do something reasonable
* to discourage usage. This practice does have some cost; for example, suppression would require
* {@code @SuppressWarnings({"DoNotCall", "deprecation"})}.
*
*
Tool support
*
* Error Prone supports this annotation via its DoNotCall pattern.
*/
@Retention(CLASS)
@Target(METHOD)
public @interface DoNotCall {
/** An optional explanation of why the method should not be called. */
String value() default "";
}