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/*
* Copyright (C) 2013-2018 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;
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 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.
* Note that this constructor is only generated if you haven't written any constructors and also haven't
* added any explicit {@code @XArgsConstructor} annotations. In those cases, lombok will assume an all-args
* constructor is present and generate code that uses it; this means you'd get a compiler error if this
* constructor is not present.
* <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
* 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 / 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 method that was annotated with {@code @Builder}. The return type of this method will be the same
* as the relevant class, unless a 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="https://projectlombok.org/features/Builder">the project lombok features page for @Builder</a>.
* <br>
* <p>
* Before:
*
* <pre>
* @Builder
* class Example<T> {
* private T 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>
*
* @see Singular
*/
@Target({TYPE, METHOD, CONSTRUCTOR})
@Retention(SOURCE)
public @interface Builder {
/**
* The field annotated with {@code @Default} must have an initializing expression; that expression is taken as the default to be used if not explicitly set during building.
*/
@Target(FIELD)
@Retention(SOURCE)
public @interface Default {}
/** @return Name of the method that creates a new builder instance. Default: {@code builder}. */
String builderMethodName() default "builder";
/** @return Name of the 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}.
* <p>
* Default for {@code @Builder} on methods: {@code (ReturnTypeName)Builder}.
*
* @return Name of the builder class that will be generated (or if it already exists, will be filled with builder elements).
*/
String builderClassName() default "";
/**
* If true, generate an instance method to obtain a builder that is initialized with the values of this instance.
* Legal only if {@code @Builder} is used on a constructor, on the type itself, or on a static method that returns
* an instance of the declaring type.
*
* @return Whether to generate a {@code toBuilder()} method.
*/
boolean toBuilder() default false;
/**
* Put on a field (in case of {@code @Builder} on a type) or a parameter (for {@code @Builder} on a constructor or static method) to
* indicate how lombok should obtain a value for this field or parameter given an instance; this is only relevant if {@code toBuilder} is {@code true}.
*
* You do not need to supply an {@code @ObtainVia} annotation unless you wish to change the default behaviour: Use a field with the same name.
* <p>
* Note that one of {@code field} or {@code method} should be set, or an error is generated.
* <p>
* The default behaviour is to obtain a value by referencing the name of the parameter as a field on 'this'.
*/
@Target({FIELD, PARAMETER})
@Retention(SOURCE)
public @interface ObtainVia {
/**
* @return Tells lombok to obtain a value with the expression {@code this.value}.
*/
String field() default "";
/**
* @return Tells lombok to obtain a value with the expression {@code this.method()}.
*/
String method() default "";
/**
* @return Tells lombok to obtain a value with the expression {@code SelfType.method(this)}; requires {@code method} to be set.
*/
boolean isStatic() default false;
}
}
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