augment the factory pattern in java

Question

I am trying to use a factory pattern to create a QuestionTypeFactory where the instantiated classes will be like MultipleChoice, TrueFalseQuestion etc.

The factory code

Answer 1

One possibility:

public enum QuestionType {
    TrueFalse(TrueFalseQuestion.class),
    MultipleChoice(MultipleChoiceQuestion.class),
    Essay(EssayQuestion.class)

    private final Class implementationType;
    QuestionType(Class implementationType) {
       this.implementationType = implementationType;
    }

    public Question createQuestion() { 
       return implementationType.newInstance(); 
    }
}

Of course, this gets rid of the factory and assumes all your questions have no-args constructors, but as far as I can tell, it covers all the cases of the code sketch above. If construction for the particularly classes is more complicated, you can always setup something like:

public enum QuestionType {
    TrueFalse { public Question createQuestion() { /* construction logic goes here */ } }
    public abstract Question createQuestion();
}