#import "../_features.html" as f> <@f.scaffold title="@SuperBuilder" logline="Bob now knows his ancestors: Builders with fields from superclasses, too. "> <@f.history>
@SuperBuilder
was introduced as experimental feature in lombok v1.18.2.
@SuperBuilder
's toBuilder
feature and limited support for customization was added with lombok v1.18.4.
The @SuperBuilder
annotation produces complex builder APIs for your classes.
In contrast to @Builder
, @SuperBuilder
also works with fields from superclasses.
However, it only works for types, and customization possibilities are limited.
Most importantly, it requires that all superclasses also have the @SuperBuilder
annotation.
@SuperBuilder
lets you automatically produce the code required to have your class be instantiable with code such as:
Person.builder().name("Adam Savage").city("San Francisco").job("Mythbusters").job("Unchained Reaction").build();
@SuperBuilder
can generate so-called 'singular' methods for collection parameters/fields. For details, see the @Singular
documentation in @Builder
.
@SuperBuilder
generates a private constructor on the class that takes a builder instance as a parameter. This constructor sets the fields of the new instance to the values from the builder.
@SuperBuilder
is not compatible with @Builder
.
You can use @SuperBuilder(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.
Using toBuilder
requires that all superclasses also have toBuilder = true
.
You can put the @Builder.ObtainVia
annotation on the fields 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")
.
To ensure type-safety, @SuperBuilder
generates two inner builder classes for each annotated class, one abstract and one concrete class named FoobarBuilder
and FoobarBuilderImpl
(where Foobar is the name of the annotated class).
Customizing the code generated by @SuperBuilder
is limited to adding new methods or annotations to the builder classes, and providing custom implementations of builder()
and build()
.
You have to make sure that the builder class declaration headers match those that would have been generated by lombok. Due to the heavy generics usage, we strongly advice to copy the builder class definition header from the uncustomized delomboked code.
The configurable aspects of builder are:
"build"
)
"builder"
)
toBuilder()
(default: no)
@SuperBuilder(buildMethodName = "execute", builderMethodName = "helloWorld", toBuilder = true)
lombok.superBuilder.flagUsage
= [warning
| error
] (default: not set)
@SuperBuilder
as a warning or error if configured.
lombok.singular.useGuava
= [true
| false
] (default: false)
true
, lombok will use guava's ImmutableXxx
builders and types to implement java.util
collection interfaces, instead of creating implementations based on Collections.unmodifiableXxx
. You must ensure that guava is actually available on the classpath and buildpath if you use this setting. Guava is used automatically if your field/parameter has one of the guava ImmutableXxx
types.
lombok.singular.auto
= [true
| false
] (default: true)
true
(which is the default), lombok automatically tries to singularize your identifier name by assuming that it is a common english plural. If false
, you must always explicitly specify the singular name, and lombok will generate an error if you don't (useful if you write your code in a language other than english).
The generated builder code heavily relies on generics to avoid class casting when using the builder.
For remarks on @Singular
, see the @Builder
documentation's small print.
Various well known annotations about nullity cause null checks to be inserted and will be copied to parameter of the builder's 'setter' method. See Getter/Setter documentation's small print for more information.
@f.smallPrint> @f.scaffold>