com.google.auto.value.AutoValue Maven / Gradle / Ivy
/*
* Copyright (C) 2012 Google, Inc.
*
* 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.auto.value;
import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Specifies that AutoValue should
* generate an implementation class for the annotated abstract class, implementing the standard
* {@link Object} methods like {@link Object#equals equals} to have conventional value semantics. A
* simple example:
*
*
*
* @AutoValue
* abstract class Person {
* static Person create(String name, int id) {
* return new AutoValue_Person(name, id);
* }
*
* abstract String name();
* abstract int id();
* }
*
* @see AutoValue User's Guide
* @author Éamonn McManus
* @author Kevin Bourrillion
*/
@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface AutoValue {
/**
* Specifies that AutoValue should generate an implementation of the annotated class or interface,
* to serve as a builder for the value-type class it is nested within. As a simple example,
* here is an alternative way to write the {@code Person} class mentioned in the {@link AutoValue}
* example:
*
*
*
* @AutoValue
* abstract class Person {
* static Builder builder() {
* return new AutoValue_Person.Builder();
* }
*
* abstract String name();
* abstract int id();
*
* @AutoValue.Builder
* interface Builder {
* Builder name(String x);
* Builder id(int x);
* Person build();
* }
* }
*
* @author Éamonn McManus
*/
@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface Builder {}
/**
* Specifies that AutoValue should copy any annotations from the annotated element to the
* generated class. This annotation supports classes and methods.
*
* The following annotations are excluded:
*
*
* - AutoValue and its nested annotations;
*
- any annotation appearing in the {@link AutoValue.CopyAnnotations#exclude} field;
*
- any class annotation which is itself annotated with the {@link
* java.lang.annotation.Inherited} meta-annotation.
*
*
* For historical reasons, annotations are always copied from an {@code @AutoValue} property
* method to its implementation, unless {@code @CopyAnnotations} is present and explicitly
* {@linkplain CopyAnnotations#exclude excludes} that annotation. But annotations are not copied
* from the {@code @AutoValue} class itself to its implementation unless {@code @CopyAnnotations}
* is present.
*
*
When the type of an {@code @AutoValue} property method has annotations, those are
* part of the type, so they are always copied to the implementation of the method.
* {@code @CopyAnnotations} has no effect here. For example, suppose {@code @Confidential} is a
* {@link java.lang.annotation.ElementType#TYPE_USE TYPE_USE} annotation:
*
*
*
* @AutoValue
* abstract class Person {
* static Person create(@Confidential String name, int id) {
* return new AutoValue_Person(name, id);
* }
*
* abstract @Confidential String name();
* abstract int id();
* }
*
* Then the implementation of the {@code name()} method will also have return type
* {@code @Confidential String}.
*
* @author Carmi Grushko
*/
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.TYPE, ElementType.METHOD})
public @interface CopyAnnotations {
Class[] exclude() default {};
}
}