QuestionController: delete old answers of same owner when a new one arrives

app/controllers/QuestionController.java

 package controllers;
 
+import java.util.List;
+
 import models.QuestionAnswer;
 import models.Session;
 import play.libs.Json;
@@ -16,7 +18,7 @@ public class QuestionController extends Controller {
 
 	/**
 	 * Creates a new {@link QuestionAnswer} for a {@link Session} from the
-	 * request body
+	 * request body and deletes the old answers from the same owner
 	 * 
 	 * @param sid
 	 *            the ID of a Session
@@ -35,6 +37,13 @@ public class QuestionController extends Controller {
 		JsonNode json = request().body().asJson();
 		QuestionAnswer answer = Json.fromJson(json, QuestionAnswer.class);
 		if (!answer.owner.isEmpty()) {
+			// Delete old answer(s)
+			List<QuestionAnswer> oldAnswers = QuestionAnswer
+					.findFromOwner(answer.owner);
+			for (QuestionAnswer qa : oldAnswers) {
+				qa.delete();
+			}
+
 			QuestionAnswer inserted = new QuestionAnswer(session, answer.owner,
 					answer.answer);
 			session.addQuestionAnswer(inserted);

app/controllers/VoteController.java

@@ -110,6 +110,7 @@ public class VoteController extends Controller {
 					sAll.value = v.value;
 					break;
 				case REQUEST:
+					// TODO: consider only last 5minutes?
 					sRequests.value += v.value.compareTo(0);
 					break;
 				default:

app/models/QuestionAnswer.java

 package models;
 
 import java.util.Date;
+import java.util.List;
 
 import javax.persistence.Entity;
 import javax.persistence.Id;
@@ -52,6 +53,10 @@ public class QuestionAnswer extends Model {
 	public static Finder<Long, QuestionAnswer> find = new Finder<Long, QuestionAnswer>(
 			Long.class, QuestionAnswer.class);
 
+	public static List<QuestionAnswer> findFromOwner(String owner) {
+		return QuestionAnswer.find.where().eq("owner", owner).findList();
+	}
+
 	public QuestionAnswer(Session session, String owner, Answer answer) {
 		this.session = session;
 		this.owner = owner;