All together now: A shortcut for @ToString
, @EqualsAndHashCode
, @Getter
on all fields, @Setter
on all non-final fields, and @RequiredArgsConstructor
!
Overview
@Data
is a convenient shortcut annotation that bundles the features of @ToString
, @EqualsAndHashCode
, @Getter
/ @Setter
and @RequiredArgsConstructor
together: In other words, @Data
generates all the boilerplate that is normally associated with simple POJOs (Plain Old Java Objects) and beans: getters for all fields, setters for all non-final fields, and appropriate toString
, equals
and hashCode
implementations that involve the fields of the class, and a constructor that initializes all final fields, as well as all non-final fields with no initializer that have been marked with @NonNull
, in order to ensure the field is never null.@Data
is like having implicit @Getter
, @Setter
, @ToString
, @EqualsAndHashCode
and @RequiredArgsConstructor
annotations on the class (except that no constructor will be generated if any explicitly written constructors already exist). However, the parameters of these annotations (such as callSuper
, includeFieldNames
and exclude
) cannot be set with @Data
. If you need to set non-default values for any of these parameters, just add those annotations explicitly; @Data
is smart enough to defer to those annotations.
All generated getters and setters will be
public
. To override the access level, annotate the field or class with an explicit @Setter
and/or @Getter
annotation. You can also use this annotation (by combining it with AccessLevel.NONE
) to suppress generating a getter and/or setter altogether.
All fields marked as
transient
will not be considered for hashCode
and equals
. All static fields will be skipped entirely (not considered for any of the generated methods, and no setter/getter will be made for them).
If the class already contains a method with the same name and parameter count as any method that would normally be generated, that method is not generated, and no warning or error is emitted. For example, if you already have a method with signature
equals(AnyType param)
, no equals
method will be generated, even though technically it might be an entirely different method due to having different parameter types. The same rule applies to the constructor (any explicit constructor will prevent @Data
from generating one), as well as toString
, equals
, and all getters and setters. You can mark any constructor or method with @lombok.experimental.Tolerate
to hide them from lombok.@Data
can handle generics parameters for fields just fine. In order to reduce the boilerplate when constructing objects for classes with generics, you can use the staticConstructor
parameter to generate a private constructor, as well as a static method that returns a new instance. This way, javac will infer the variable name. Thus, by declaring like so: @Data(staticConstructor="of") class Foo<T> { private T x;}
you can create new instances of Foo
by writing: Foo.of(5);
instead of having to write: new Foo<Integer>(5);
.With Lombok
import lombok.AccessLevel; |
Vanilla Java
import java.util.Arrays; |
Supported configuration keys:
lombok.data.flagUsage
= [warning
|error
] (default: not set)- Lombok will flag any usage of
@Data
as a warning or error if configured.
Small print
See the small print of
@ToString
, @EqualsAndHashCode
, @Getter / @Setter
and @RequiredArgsConstructor.
Various well known annotations about nullity cause null checks to be inserted and will be copied to the relevant places (such as the method for getters, and the parameter for the constructor and setters). See Getter/Setter documentation's small print for more information.
By default, any variables that start with a $ symbol are excluded automatically. You can include them by specifying an explicit annotation (
@Getter
or @ToString
, for example) and using the 'of' parameter.Reference:
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