augment the factory pattern in java
- by TP
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 looks something like this
class QuestionFactory {
public enum QuestionType {
TrueFalse,
MultipleChoice,
Essay
}
public static Question createQuestion(QuestionType quesType) {
switch (quesType) {
case TrueFalse:
return new TrueFalseQuestion();
case MultipleChoice:
return new MultipleChoiceQuestion();
case Essay:
return new EssayQuestion();
}
throw new IllegalArgumentException("Not recognized.");
}
}
This works ok for now. If I want to add another question type I will need to modify the factory class and I do not want to do that.
How can I set it up so that each question class registers itself with the Factory so that when I add a new question type, I do not have to change the code for the factory? I am a bit new to java and am not sure how to do this.
