Lombok: Difference between revisions
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* https://projectlombok.org | * https://projectlombok.org | ||
* Latest Version: https://projectlombok.org/download | |||
=Overview= | =Overview= | ||
Lombok is a Java annotation library that helps reduce boilerplate code. | Lombok is a Java annotation library that helps reduce boilerplate code. It uses annotation processing as a bootstrapping mechanism to include itself into the compilation process and modify the [[Formal_Languages_and_Translators#.28Abstract.29_Syntax_Tree|AST]] via internal compiler APIs. <span id='Not_a_Typical_Use'></span>This is not a typical use of [[Java Annotation Processor|annotation processing]], which usually generate new files and do not change existing ones. | ||
=Gradle Dependency= | =Gradle Dependency= | ||
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<syntaxhighlight lang='groovy'> | <syntaxhighlight lang='groovy'> | ||
dependencies { | dependencies { | ||
implementation | |||
implementation "org.projectlombok:lombok:1.18.2" | |||
} | } | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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Generates: | Generates: | ||
* Getters for all fields | * Getters for all fields. | ||
* Setters for all non-final fields | * Setters for all non-final fields. | ||
* A constructor with | * A constructor with required arguments: final fields and fields with constraints such as [[#.40NonNull|@NonNull]]. | ||
* A useful toString() method | * A useful toString() method. | ||
* hashCode() and equals() implementations that check all non-transient fields | * hashCode() and equals() implementations that check all non-transient fields. | ||
Equivalent to [[#@Getter|@Getter]] [[#@Setter|@Setter]], [[#@RequiredArgsConstructor|@RequiredArgsConstructor]] [[#@ToString|@ToString]] [[#@EqualsAndHashCode|@EqualsAndHashCode]] | Equivalent to [[#@Getter|@Getter]] [[#@Setter|@Setter]], [[#@RequiredArgsConstructor|@RequiredArgsConstructor]] [[#@ToString|@ToString]] [[#@EqualsAndHashCode|@EqualsAndHashCode]] | ||
==<span id='@Getter'></span><span id='@Setter'></span> | ==<span id='@Getter'></span><span id='@Setter'></span>@Getter/@Setter== | ||
{{External|[https://projectlombok.org/features/GetterSetter Lombok Documentation for Getter/Setter]}} | {{External|[https://projectlombok.org/features/GetterSetter Lombok Documentation for Getter/Setter]}} | ||
= | By default, the getters/setters such generated are public. To change the access level: | ||
<syntaxhighlight lang='java'> | |||
@Setter(AccessLevel.PACKAGE) | |||
public class ... { | |||
... | |||
} | |||
</syntaxhighlight> | |||
==Constructors== | |||
==@RequiredArgsConstructor== | {{External|[https://projectlombok.org/features/constructor Lombok Documentation for constructors]}} | ||
===@AllArgsConstructor=== | |||
===@RequiredArgsConstructor=== | |||
Generates a constructor with required arguments. Required arguments are final fields and fields with constraints such as [[#.40NonNull|@NonNull]]. | Generates a constructor with required arguments. Required arguments are final fields and fields with constraints such as [[#.40NonNull|@NonNull]]. | ||
==@NoArgsConstructor== | ===@NoArgsConstructor=== | ||
<syntaxhighlight lang='java'> | <syntaxhighlight lang='java'> | ||
Latest revision as of 02:16, 13 March 2019
External
- https://projectlombok.org
- Latest Version: https://projectlombok.org/download
Overview
Lombok is a Java annotation library that helps reduce boilerplate code. It uses annotation processing as a bootstrapping mechanism to include itself into the compilation process and modify the AST via internal compiler APIs. This is not a typical use of annotation processing, which usually generate new files and do not change existing ones.
Gradle Dependency
dependencies {
implementation "org.projectlombok:lombok:1.18.2"
}
Annotations
@Slf4j
The annotation generates a SLF4J Logger in the class. It has the same effect as if you were to explicitly add the following lines within the class:
private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(MyClass.class);
@Data
Generates:
- Getters for all fields.
- Setters for all non-final fields.
- A constructor with required arguments: final fields and fields with constraints such as @NonNull.
- A useful toString() method.
- hashCode() and equals() implementations that check all non-transient fields.
Equivalent to @Getter @Setter, @RequiredArgsConstructor @ToString @EqualsAndHashCode
@Getter/@Setter
By default, the getters/setters such generated are public. To change the access level:
@Setter(AccessLevel.PACKAGE)
public class ... {
...
}
Constructors
@AllArgsConstructor
@RequiredArgsConstructor
Generates a constructor with required arguments. Required arguments are final fields and fields with constraints such as @NonNull.
@NoArgsConstructor
@NoArgsConstructor(access=AccessLevel.PRIVATE, force=true)
Generates a no-argument constructor and make it private. This is usually applied to JPA @Entity classes. If the class has final properties that must be set, use "force=true", which results in the Lombok-generated constructor setting them to null. Note that when you use @NoArgsConstructor, an argument constructor, even if possible, will not get added, so if you need it, you will need to explicitly use @RequiredArgsConstructor.
@ToString
@EqualsAndHashCode
@NonNull
@Builder
Troubleshooting
lombok.javac.apt.LombokProcessor could not be initialized. Lombok will not run during this compilation
When using:
dependencies {
implementation('org.projectlombok:lombok')
}
we get:
warning: lombok.javac.apt.LombokProcessor could not be initialized. Lombok will not run during this compilation: java.lang.ClassCastException: org.gradle.api.internal.tasks.compile.processing.IncrementalFiler cannot be cast to com.sun.tools.javac.processing.JavacFiler
Fixed by explicitly specifying the Lombok version:
dependencies {
implementation('org.projectlombok:lombok:1.18.2')
}