When I try to use this code I do not generate objects and when printing it says that it is empty.
List<Question> questions = new ArrayList();
ChoicesQuestion q = new ChoicesQuestion();
ChoicesAnswer a = new ChoicesAnswer();
q.setText("La tierra es redonda?");
q.setChoices().add(new Choice("Verdadero", true));
q.setChoices().add(new Choice("Falso", false));
questions.add(q);
System.out.println(q.setChoices().isEmpty());
If you need to see the complete library here: link
The problem is in the class ChoicesQuestion specifically in the method setChoices since every time you call that method returns a ArrayList empty.
To make your code work, you should do the following:
In the property declaration (class ChoicesQuestion) initialize your list of options
private Collection<Choice> choices = new ArrayList();
Then use the getChoices() method to get that reference
public Collection<Choice> getChoices() {
return choices;
}
It would stay like this:
List<Question> questions = new ArrayList();
ChoicesQuestion q = new ChoicesQuestion();
ChoicesAnswer a = new ChoicesAnswer();
q.setText("La tierra es redonda?");
q.getChoices().add(new Choice("Verdadero", true));
q.getChoices().add(new Choice("Falso", false));
questions.add(q);
System.out.println(q.getChoices().isEmpty());
Simple Option
Change this line in your class ChoicesQuestions :
public Collection<Choice> setChoices() {
return choices;
}
I have initialized the collection in the constructor
public ChoicesQuestions () { this.choices = new ArrayList < > (); }
Rebooted Option
Just as you have it, you will create some confusion in the code, but it can be valid to shorten what you write a bit. (Personally I really like doing this in the set but I have found problems with debugging and reading)
I would change this line in your class ChoicesQuestions :
public Collection<Choice> setChoices() {
return new ArrayList<>();
}
for this one:
public Collection<Choice> setChoices(Choice choice) {
choices.add(choice);
return this;
}
Not without first initializing the collection.
private Collection<Choice> choices = new ArrayList<>();
This can also be done in the constructor for added security.
Then I would call in this way to add continuously:
q.setChoices(new Choice("Verdadero", verdadero))
.setChoices(new Choice("Falso", false));