source: TraumaOntologies/src/main/java/tudelft/healthpsychology/traumaontologies/answerstate/ListOfAnswersState.java

package tudelft.healthpsychology.traumaontologies.answerstate;

import java.util.Collection;
import java.util.LinkedList;
import java.util.List;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;

import tudelft.healthpsychology.traumaontologies.questiontypes.TypedQuestion;
import tudelft.utilities.tree.Tree;

/**
 * A list of {@link AnswerState}s, to be answered one by one in given order.
 */
public class ListOfAnswersState implements AnswerState {
        private final List<AnswerState> answerStates;

        @JsonCreator
        public ListOfAnswersState(
                        @JsonProperty("answerStates") List<AnswerState> answerStates) {
                this.answerStates = answerStates;
        }

        @Override
        public TypedQuestion getOptions(
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                Integer i = active(tree);
                return i == null ? null : answerStates.get(i).getOptions(tree);
        }

        @Override
        public AnswerState with(String answer,
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                Integer i = active(tree);
                if (i == null)
                        throw new IllegalStateException("State is final");

                LinkedList<AnswerState> newAnswersStates = new LinkedList<AnswerState>(
                                answerStates);
                newAnswersStates.set(i, answerStates.get(i).with(answer, tree));
                return new ListOfAnswersState(newAnswersStates);
        }

        /**
         * @return index of the active answerstate in {@link #answerStates}, or null
         *         if no active state.
         */
        private Integer active(
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                for (int i = 0; i < answerStates.size(); i++) {
                        if (answerStates.get(i).getOptions(tree) != null) {
                                return i;
                        }
                }
                return null;
        }
}