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viana
Asked: 2020-10-06 11:24:00 +0800 CST 2020-10-06 11:24:00 +0800 CST

What is the purpose of the "data class"?

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In Kotlin you can create a class like this:

data class Dragon(private val nombre: String, val type: Int)

What is the main goal of the data classin Kotlin? When should we use?

kotlin

1 Answers

  1. Best Answer

    It was created for DTOs: Data Transfer Objects.

    Many times we create classes that serve only and purely to pass data such as the class Usuarioand creating them is a headache for something so simple:

    public class Usuario
{
  private String username;
  private String password;
  private int userId;

  public void setUserName(Strin username)
  {
    this.username = username;
  }

  public void setPassword(String password)
  {
    this.password = password;
  }

  public void setId(int id)
  {
    this.userId = id;
  }

  public String getUserName()
  {
    return username;
  }

  public String getPassword()
  {
    return this.password;
  }

  public String getId()
  {
    return this.userId;
  }
}

    Although IDEs like android studio help with the generation of getters/setters, it's too much code for something as simple as transporting data.

    Kotlin boils all that down to this:

    data class Usuario(val username: String, val password: String, val id: int)

    And it automatically generates the getters and setters without the need for so many rituals.

    As mentioned at the beginning, data classes are only for classes that serve information and that's it, without any logic involved.

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