Lombok Constructors

easy constructors with lombok

05 May 2017    250 words    1 minutes reading     Post a comment

In the post Lombok Getters and Setters, we talked about the use of Lombok to provide quick and easy getters and setters.

In this post, I will cover another great feature from Lombok, that provides quick and easy constructors. For this post, I will use Lombok v1.16.16.

In Lombok, we have 3 different annotations to deal with constructors:

  • NoArgsConstructor: mostly used to create a constructor with different access modification, preventing it from being accessed from other classes;
  • AllArgsConstructor: will create constructor receiving all non-static fields;
  • RequiredArgsConstructor: will create constructor receiving non-static final fields.

We are mostly interested in the second and third items, that are more commonly used.

AllArgsConstructor

The @AllArgsConstructor annotation creates the constructor with all the fields as parameters. In this example, it’s exemplified in the static block.

It’s also possible to change the constructor’s access modifier. In the following example, it’s providing protected access modifier, that will prevent accesses from classes that are not inheriting from the specified class.

RequiredArgsConstructor

The @RequiredArgsConstructor works the same way as @AllArgsConstructor. However, it only considers the fields that are non-static and final. It guarantees that the fields covered will not be changed after construction, once it requires them to be final.

Conclusion

Once more, we use Lombok to reduce boilerplate code in our applications. We can make use of these features to increase the readability of our classes.