@Documented @Retention(value=RUNTIME) @Target(value={TYPE,CONSTRUCTOR,METHOD}) public @interface Builder
@Builder
AST transformation is used to help write classes that can be created using fluent api calls.
The transform supports multiple building strategies to cover a range of cases and there are a number
of configuration options to customize the building process.
In addition, a number of annotation attributes let you customise the building process. Not all annotation attributes
are supported by all strategies. See the individual strategy documentation for more details.
If you're an AST hacker, you can also define your own strategy class.
The following strategies are bundled with Groovy:
SimpleStrategy
for creating chained settersExternalStrategy
where you annotate an explicit builder class while leaving some buildee class being built untouchedDefaultStrategy
which creates a nested helper class for instance creationInitializerStrategy
which creates a nested helper class for instance creation which when used with @CompileStatic
allows type-safe object creationnew Person(firstName: "Robert", lastName: "Lewandowski", age: 21)or the with statement:
new Person().with { firstName = "Robert" lastName = "Lewandowski" age = 21 }so you might not find value in using the builder transform at all. But if you need Java integration or in some cases improved type safety, the
@Builder
transform might prove very useful.SimpleStrategy
,
ExternalStrategy
,
DefaultStrategy
,
InitializerStrategy
Modifier and Type | Optional Element and Description |
---|---|
String |
builderClassName
For strategies which create a builder helper class, the class name to use for the helper class.
|
String |
builderMethodName
The method name to use for a builder factory method in the source class for easy access of the
builder helper class for strategies which create such a helper class.
|
Class<? extends BuilderASTTransformation.BuilderStrategy> |
builderStrategy
A class capturing the builder strategy
|
String |
buildMethodName
For strategies which create a builder helper class that creates the instance, the method name to call to create the instance.
|
String[] |
excludes
List of field and/or property names to exclude from generated builder methods.
|
Class |
forClass
A class for which builder methods should be created.
|
String[] |
includes
List of field and/or property names to include within the generated builder methods.
|
String |
prefix
The prefix to use when creating the setter methods.
|
public abstract Class forClass
public abstract Class<? extends BuilderASTTransformation.BuilderStrategy> builderStrategy
public abstract String prefix
public abstract String builderClassName
forClass
since in such cases the builder class is explicitly supplied.
Default is determined by the strategy, e.g. TargetClass + "Builder" or TargetClass + "Initializer".public abstract String buildMethodName
public abstract String builderMethodName
forClass
.
Default is determined by the strategy, e.g. builder or createInitializer.public abstract String[] excludes
public abstract String[] includes