Now that the "method" mode is clear, putting a @Builder annotation on a constructor functions similarly; effectively, constructors are just static methods that have a special syntax to invoke them: Their 'return type' is the class they construct, and their type parameters are the same as the type parameters of the class itself.
- Finally, applying @Builder to a class is as if you added @AllArgsConstructor(access = AccessLevel.PACKAGE) to the class and applied the @Builder annotation to this all-args-constructor. This only works if you haven't written any explicit constructors yourself or created one with @NoArgsConstructor. If you do have an explicit constructor, put the @Builder annotation on the constructor instead of on the class. Note that if you put both `@Value` and `@Builder` on a class, the package-private constructor that `@Builder` wants to generate 'wins' and suppresses the constructor that `@Value` wants to make.
+ Finally, applying @Builder to a class is as if you added @AllArgsConstructor(access = AccessLevel.PACKAGE) to the class and applied the @Builder annotation to this all-args-constructor. This only works if you haven't written any explicit constructors yourself or allowed lombok to create one such as with @NoArgsConstructor. If you do have an explicit constructor, put the @Builder annotation on the constructor instead of on the class. Note that if you put both `@Value` and `@Builder` on a class, the package-private constructor that `@Builder` wants to generate 'wins' and suppresses the constructor that `@Value` wants to make.
If using @Builder to generate builders to produce instances of your own class (this is always the case unless adding @Builder to a method that doesn't return your own type), you can use @Builder(toBuilder = true) to also generate an instance method in your class called toBuilder(); it creates a new builder that starts out with all the values of this instance. You can put the @Builder.ObtainVia annotation on the parameters (in case of a constructor or method) or fields (in case of @Builder on a type) to indicate alternative means by which the value for that field/parameter is obtained from this instance. For example, you can specify a method to be invoked: @Builder.ObtainVia(method = "calculateFoo").