Support Polymorphism

[simschla]

I would love to have support for polymorphism in Builderberg.

Simple example:

public abstract class Vehicle {
    private final String make;
    // [...]
}

public class Car extends Vehicle {
    private final int seatingCapacity;
    // [...]
}

public class Truck extends Vehicle {
    private final int payloadCapacity;
    // [...]
}

As a suggestion, this is how resulting builders could look like:

public abstract class Vehicle {
    // [...]

    // protected instead of public?
    // non-final?
    protected static class Builder {
        // [ all fields of type Vehicle ]
    }
}

public class Car extends Vehicle {
    // [...]

    public static final class Builder extends Vehicle.Builder {
        // [ all fields of type Car ]

        // PLUS:
        // Overrides for all methods of Vehicle.Builder (in order to allow strongly-typed fluent usage) - delegating to Vehicle.Builder but casting return value to Car.Builder)
    }
}