Step Builder Generator Plugin for JetBrains IntelliJ IDEA

What is it?

Based on the Builder creational design pattern, this plugin generates an internal Step Builder for a class. A Step Builder guides the users of your class through the creation process without creating objects with inconsistent internal state.

Where do I find the plugin when it is installed?

You can find an additional action in the "Generate..." menu.

How do I start?

Implement the easiest version of your class, e.g.:

public class Person {
    protected final String firstName;
    protected final String lastName;
    protected int age;
    protected boolean active;
}

Even though this class will not compile as is (final fields need to be initialized at once or in constructors), it is a good starting point for the Step Builder. The plugin uses all final fields as mandatory fields, creating explicit Step interfaces for them. All non-final fields are considered optional. A private constructor having parameters for all final fields is created (all other constructors will be removed), as well as getters for all fields. The starting point, a static method called "newInstance", is added to the class.

What's the benefit for the users of my class?

Users of your class will leverage the Step Builder whenever they need to create new instances. Example:

Person p = Person.newInstance()
                 .firstName("John")
                 .lastName("Doe")
                 .age(27)
                 .active(true)
                 .build();

Additional resources about the Builder pattern and the Step Builder:

Crisp's Blog - Another builder pattern for Java

Remove duplications and fix bad names: Step Builder pattern