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Immutable value-type code generation for Java 1.6+.
There is a newer version: 1.11.0
/*
 * 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.SOURCE)
  @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.
   * 
   *
   * 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.SOURCE)
  @Target({ElementType.TYPE, ElementType.METHOD})
  public @interface CopyAnnotations {
    Class[] exclude() default {};
  }
}