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/*
* Copyright (C) 2013 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.experimental;
import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* The builder annotation creates a so-called 'builder' aspect to the class that is annotated or the class
* that contains a member which is annotated with {@code @Builder}.
* <p>
* If a member is annotated, it must be either a constructor or a static method. If a class is annotated,
* then a private constructor is generated with all fields as arguments
* (as if {@code @AllArgsConstructor(AccessLevel.PRIVATE)} is present
* on the class), and it is as if this constructor has been annotated with {@code @Builder} instead.
* <p>
* The effect of {@code @Builder} is that an inner class is generated named <code><strong>T</strong>Builder</code>,
* with a private constructor. Instances of <code><strong>T</strong>Builder</code> are made with the static
* method named {@code builder()} which is also generated for you in the class itself (not in the builder class).
* <p>
* The <code><strong>T</strong>Builder</code> class contains 1 method for each parameter of the annotated
* constructor / static method (each field, when annotating a class), which returns the builder itself.
* The builder also has a <code>build()</code> method which returns a completed instance of the original type,
* created by passing all parameters as set via the various other methods in the builder to the constructor
* or static method that was annotated with {@code @Builder}. The return type of this method will be the same
* as the relevant class, unless a static method has been annotated, in which case it'll be equal to the
* return type of that method.
* <p>
* Complete documentation is found at <a href="http://projectlombok.org/features/experimental/Builder.html">the project lombok features page for @Builder</a>.
* <p>
* <p>
* Before:
*
* <pre>
* @Builder
* class Example {
* private int foo;
* private final String bar;
* }
* </pre>
*
* After:
*
* <pre>
* class Example<T> {
* private T foo;
* private final String bar;
*
* private Example(T foo, String bar) {
* this.foo = foo;
* this.bar = bar;
* }
*
* public static <T> ExampleBuilder<T> builder() {
* return new ExampleBuilder<T>();
* }
*
* public static class ExampleBuilder<T> {
* private T foo;
* private String bar;
*
* private ExampleBuilder() {}
*
* public ExampleBuilder foo(T foo) {
* this.foo = foo;
* return this;
* }
*
* public ExampleBuilder bar(String bar) {
* this.bar = bar;
* return this;
* }
*
* @java.lang.Override public String toString() {
* return "ExampleBuilder(foo = " + foo + ", bar = " + bar + ")";
* }
*
* public Example build() {
* return new Example(foo, bar);
* }
* }
* }
* </pre>
*/
@Target({TYPE, METHOD, CONSTRUCTOR})
@Retention(SOURCE)
public @interface Builder {
/** Name of the static method that creates a new builder instance. Default: {@code builder}. */
String builderMethodName() default "builder";
/** Name of the instance method in the builder class that creates an instance of your {@code @Builder}-annotated class. */
String buildMethodName() default "build";
/** Name of the builder class.
* Default for {@code @Builder} on types and constructors: {@code (TypeName)Builder}.
* Default for {@code @Builder} on static methods: {@code (ReturnTypeName)Builder}.
*/
String builderClassName() default "";
}
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