javaadvent_sample3.java

public static class Builder implements WannabeApplicative<Message> {

    private String _text;
    private Integer _number;

    public Builder text(String text){
        _text=text;
        return this;
    }

    public Builder number(Integer number){
        _number=number;
        return this;
    }

    @Override
    public Message apply() {
        return new Message(_text,_number);
    }
}