Discussion on: "Builder Pattern" generator for Java

[riversun]

I supported the source code generation of the Builder pattern that can forcibly set the mandatory property in the correct order.

Here is an example code auto generated with my tool.(select Mandatory Properties)

package com.example;
import java.util.Optional;

public class Person {

  private final String name;// Required
  private final Integer age;// Required
  private final String gender;// Required
  private final Integer height;// Required
  private final Optional<String> eyeColor;// Optional(use Optional<String>)
  private final Optional<String> hairColor;// Optional(use Optional<String>)
  private final Optional<String> hobby;// Optional(use Optional<String>)

  Person(Builder.Builder1 builder) {
    this.name = builder.name; 
    this.age = builder.age; 
    this.gender = builder.gender; 
    this.height = builder.height; 
    this.eyeColor = builder.eyeColor; 
    this.hairColor = builder.hairColor; 
    this.hobby = builder.hobby; 
  }
  public static Builder builder() {
    return new Builder();
  }

  public static final class Builder {
    public Builder1 name(String name) {
      return new Builder1(name);
    }
    public static final class Builder1 {
      final String name;
      Integer age;
      String gender;
      Integer height;
      Optional<String> eyeColor;
      Optional<String> hairColor;
      Optional<String> hobby;

      private Builder1(String name) {
        this.name = name;
      }
      public Builder2 age(Integer age) {
        this.age = age;
        return new Builder2(Builder1.this);
      }
    }
    public static final class Builder2 {
      final Builder1 builder;

      private Builder2(Builder1 builder) {
        this.builder = builder;
      }
      public Builder3 gender(String gender) {
        this.builder.gender = gender;
        return new Builder3(this.builder);
      }
    }
    public static final class Builder3 {
      final Builder1 builder;

      private Builder3(Builder1 builder) {
        this.builder = builder;
      }
      public Builder4 height(Integer height) {
        this.builder.height = height;
        return new Builder4(this.builder);
      }
    }
    public static final class Builder4 {
      final Builder1 builder;

      private Builder4(Builder1 builder) {
        this.builder = builder;
      }
      public Builder4 eyeColor(String eyeColor){
        this.builder.eyeColor = Optional.of(eyeColor);
        return this;
      }
      public Builder4 hairColor(String hairColor){
        this.builder.hairColor = Optional.of(hairColor);
        return this;
      }
      public Builder4 hobby(String hobby){
        this.builder.hobby = Optional.of(hobby);
        return this;
      }
      public Person build() {
        return new Person(this.builder);
      }
    }
  }

  public String name() {
    return this.name;
  }
  public Integer age() {
    return this.age;
  }
  public String gender() {
    return this.gender;
  }
  public Integer height() {
    return this.height;
  }
  public Optional<String> eyeColor() {
    return this.eyeColor;
  }
  public Optional<String> hairColor() {
    return this.hairColor;
  }
  public Optional<String> hobby() {
    return this.hobby;
  }

  @Override
  public String toString() {
    return "Person(name=" + this.name + ", age=" + this.age + ", gender=" + this.gender + ", height=" + this.height + ", eyeColor=" + this.eyeColor + ", hairColor=" + this.hairColor + ", hobby=" + this.hobby + ")";
  }

  public void doSomething() {
      // do something
  }
}