index.md

title: Lombok author: name: "Thomas Queste" url: "tomsquest.com" email: "[email protected]" twitter: "@ThomasQueste" output: index.html style: index.css controls: false

Lombok

Goals

1. Reduce boilerplate
2. Reduce maintenance --

@Builder

Given:

@Builder
public class Line {
    private String adresseLigne1;
    private String codePostal;
    private String ville;
    private CountryCode country;
}

Usage:

Line line = Line.builder()
            .adresseLigne1("adresseLigne1")
            .codePostal("codePostal")
            .ville("ville")
            .countryCode(CountryCode.DE)
            .build();

--

@Value = Immutable

Given:

@Value
public class Point {
    private int x;
    private int y;
}

Usage:

Point p = new Point(x,y);
p.getX()
p.getY()
p.toString()

new Point(1.2).equals( new Point(3,4) ) // + hashcode

--

@Data = Java Bean

Given:

@Data
public class Point {
    private int x;
    private int y;
}

Usage:

Point p = new Point();
p.setX(1)
p.setY(2)
p.toString()
new Point(1.2).equals( new Point(3,4) ) // + hashcode

--

Setup

Maven, Gradle, And, Kobalt...

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.18</version>
    <scope>provided</scope>
</dependency>

Required IDE plugins for Intellij, Eclipse, Netbeans...

Delombok

Some stable features

• @Log: declare a logger
• val: final local variable + type inferred
• @NonNull: checks for nulls
• @Getter/@Setter
• @ToString
• @EqualsAndHashCode
• @NoArgsConstructor, @RequiredArgsConstructor, @AllArgsConstructor
  --

Some Experimental features

--

@Accessors

Fluent API for getters and setters, return this instead of void in setters

public Line country(CountryCode country) {
    this.country = country;
    return this;
}

line
  .country(FR)
  .name("FOO")

--

@Wither

Immutable 'setters' - methods that create a clone but with one changed field

public Line withCountry(CountryCode country) {
    return this.country == country ? this : new Line(idSocle, prenom, nom, country);
}

Line line2 = line1.withCountry(FR)

--

Caveats

• IDE Plugin needed
• Source annotation enabled
• Java 9 unsupported as of 2017.10
• Many opened issues & PR