Index: lams_central/src/java/org/lamsfoundation/lams/web/outcome/OutcomeController.java
===================================================================
diff -u -r67db3e1b2ada0d59ff98c807a54282783797c5e6 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_central/src/java/org/lamsfoundation/lams/web/outcome/OutcomeController.java	(.../OutcomeController.java)	(revision 67db3e1b2ada0d59ff98c807a54282783797c5e6)
+++ lams_central/src/java/org/lamsfoundation/lams/web/outcome/OutcomeController.java	(.../OutcomeController.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -22,10 +22,7 @@
 
 package org.lamsfoundation.lams.web.outcome;
 
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.Date;
-import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -46,6 +43,7 @@
 import org.lamsfoundation.lams.outcome.OutcomeScale;
 import org.lamsfoundation.lams.outcome.OutcomeScaleItem;
 import org.lamsfoundation.lams.outcome.service.IOutcomeService;
+import org.lamsfoundation.lams.outcome.service.OutcomeService;
 import org.lamsfoundation.lams.security.ISecurityService;
 import org.lamsfoundation.lams.usermanagement.Role;
 import org.lamsfoundation.lams.usermanagement.User;
@@ -309,7 +307,7 @@
 
 	List<OutcomeMapping> outcomeMappings = outcomeService.getOutcomeMappings(lessonId, toolContentId, itemId,
 		qbQuestionId);
-	OutcomeController.filterQuestionMappings(outcomeMappings);
+	OutcomeService.filterQuestionMappings(outcomeMappings);
 
 	ArrayNode responseJSON = JsonNodeFactory.instance.arrayNode();
 	for (OutcomeMapping outcomeMapping : outcomeMappings) {
@@ -645,32 +643,4 @@
 	    errorMap.add("GLOBAL", messageService.getMessage("outcome.manage.add.error.code.blank"));
 	}
     }
-
-    /**
-     * There can be duplicates in mappings, if one comes from activity and the other comes from a QB question that the
-     * activity imported.
-     * We need to get rid of duplicates and sort the remaining mappings.
-     */
-    private static void filterQuestionMappings(List<OutcomeMapping> mappings) {
-	Iterator<OutcomeMapping> iterator = mappings.iterator();
-	while (iterator.hasNext()) {
-	    OutcomeMapping mapping = iterator.next();
-	    boolean duplicateFound = false;
-	    for (OutcomeMapping otherMapping : mappings) {
-		if (!mapping.getMappingId().equals(otherMapping.getMappingId())
-			&& mapping.getOutcome().getOutcomeId().equals(otherMapping.getOutcome().getOutcomeId())) {
-		    duplicateFound = true;
-		    break;
-		}
-	    }
-	    // remove the one coming from activity, not one coming from question
-	    if (duplicateFound && mapping.getQbQuestionId() == null) {
-		iterator.remove();
-	    }
-	}
-
-	Collections.sort(mappings,
-		Comparator.comparing(OutcomeMapping::getOutcome, Comparator.comparing(Outcome::getName)));
-    }
-
 }
\ No newline at end of file
Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java
===================================================================
diff -u -r0b1e74374b821758fdda7835d8d283bf84fa8db0 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java	(.../QbStatsController.java)	(revision 0b1e74374b821758fdda7835d8d283bf84fa8db0)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java	(.../QbStatsController.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -1,87 +1,108 @@
-/****************************************************************
- * Copyright (C) 2005 LAMS Foundation (http://lamsfoundation.org)
- * =============================================================
- * License Information: http://lamsfoundation.org/licensing/lams/2.0/
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2.0
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 * USA
- *
- * http://www.gnu.org/licenses/gpl.txt
- * ****************************************************************
- */
-
-package org.lamsfoundation.lams.web.qb;
-
-import java.util.Collection;
-
-import javax.servlet.http.HttpSession;
-
-import org.apache.log4j.Logger;
-import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
-import org.lamsfoundation.lams.qb.model.QbCollection;
-import org.lamsfoundation.lams.qb.service.IQbService;
-import org.lamsfoundation.lams.usermanagement.dto.UserDTO;
-import org.lamsfoundation.lams.util.Configuration;
-import org.lamsfoundation.lams.util.ConfigurationKeys;
-import org.lamsfoundation.lams.util.MessageService;
-import org.lamsfoundation.lams.web.session.SessionManager;
-import org.lamsfoundation.lams.web.util.AttributeNames;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.stereotype.Controller;
-import org.springframework.ui.Model;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestParam;
-
-@Controller
-@RequestMapping("/qb/stats")
-public class QbStatsController {
-    private static Logger log = Logger.getLogger(QbStatsController.class);
-
-    @Autowired
-    @Qualifier("centralMessageService")
-    private MessageService messageService;
-
-    @Autowired
-    private IQbService qbService;
-
-    @RequestMapping("/show")
-    public String showStats(@RequestParam long qbQuestionUid, Model model) throws Exception {
-	QbStatsDTO stats = qbService.getQuestionStats(qbQuestionUid);
-	model.addAttribute("stats", stats);
-
-	Collection<QbCollection> existingCollections = qbService.getQuestionCollectionsByUid(qbQuestionUid);
-	model.addAttribute("existingCollections", existingCollections);
-
-	Integer userId = getUserId();
-	Collection<QbCollection> availableCollections = qbService.getUserCollections(userId);
-	availableCollections.removeAll(existingCollections);
-	model.addAttribute("availableCollections", availableCollections);
-
-	boolean permanentRemove = existingCollections.size() <= 1;
-	model.addAttribute("permanentRemove", permanentRemove);
-	model.addAttribute("permanentRemovePossible",
-		permanentRemove ? qbService.removeQuestionPossibleByUid(qbQuestionUid) : false);
-
-	model.addAttribute("transferAllowed",
-		Configuration.getAsBoolean(ConfigurationKeys.QB_COLLECTIONS_TRANSFER_ALLOW));
-
-	return "qb/stats";
-    }
-
-    private Integer getUserId() {
-	HttpSession ss = SessionManager.getSession();
-	UserDTO user = (UserDTO) ss.getAttribute(AttributeNames.USER);
-	return user != null ? user.getUserID() : null;
-    }
+/****************************************************************
+ * Copyright (C) 2005 LAMS Foundation (http://lamsfoundation.org)
+ * =============================================================
+ * License Information: http://lamsfoundation.org/licensing/lams/2.0/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2.0
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 * USA
+ *
+ * http://www.gnu.org/licenses/gpl.txt
+ * ****************************************************************
+ */
+
+package org.lamsfoundation.lams.web.qb;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.servlet.http.HttpSession;
+
+import org.apache.log4j.Logger;
+import org.lamsfoundation.lams.outcome.OutcomeMapping;
+import org.lamsfoundation.lams.outcome.service.IOutcomeService;
+import org.lamsfoundation.lams.outcome.service.OutcomeService;
+import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
+import org.lamsfoundation.lams.qb.model.QbCollection;
+import org.lamsfoundation.lams.qb.service.IQbService;
+import org.lamsfoundation.lams.usermanagement.dto.UserDTO;
+import org.lamsfoundation.lams.util.Configuration;
+import org.lamsfoundation.lams.util.ConfigurationKeys;
+import org.lamsfoundation.lams.util.MessageService;
+import org.lamsfoundation.lams.web.session.SessionManager;
+import org.lamsfoundation.lams.web.util.AttributeNames;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@Controller
+@RequestMapping("/qb/stats")
+public class QbStatsController {
+    private static Logger log = Logger.getLogger(QbStatsController.class);
+
+    @Autowired
+    @Qualifier("centralMessageService")
+    private MessageService messageService;
+
+    @Autowired
+    private IQbService qbService;
+
+    @Autowired
+    private IOutcomeService outcomeService;
+
+    @RequestMapping("/show")
+    public String showStats(@RequestParam long qbQuestionUid, Model model) throws Exception {
+	QbStatsDTO stats = qbService.getQuestionStats(qbQuestionUid);
+	model.addAttribute("stats", stats);
+
+	Integer userId = getUserId();
+	int qbQuestionId = stats.getQuestion().getQuestionId();
+	boolean managementAllowed = qbService.isQuestionInUserCollection(qbQuestionId, userId);
+	model.addAttribute("managementAllowed", managementAllowed);
+
+	Collection<QbCollection> existingCollections = qbService.getQuestionCollectionsByUid(qbQuestionUid);
+	model.addAttribute("existingCollections", existingCollections);
+
+	if (managementAllowed) {
+	    Collection<QbCollection> availableCollections = qbService.getUserCollections(userId);
+	    availableCollections.removeAll(existingCollections);
+	    model.addAttribute("availableCollections", availableCollections);
+
+	    boolean permanentRemove = existingCollections.size() <= 1;
+	    model.addAttribute("permanentRemove", permanentRemove);
+	    model.addAttribute("permanentRemovePossible",
+		    permanentRemove ? qbService.removeQuestionPossibleByUid(qbQuestionUid) : false);
+
+	    model.addAttribute("transferAllowed",
+		    Configuration.getAsBoolean(ConfigurationKeys.QB_COLLECTIONS_TRANSFER_ALLOW));
+
+	} else {
+	    List<OutcomeMapping> outcomeMappings = outcomeService.getOutcomeMappings(null, null, null, qbQuestionId);
+	    OutcomeService.filterQuestionMappings(outcomeMappings);
+	    List<String> outcomes = outcomeMappings.stream()
+		    .collect(Collectors.mapping(m -> m.getOutcome().getName(), Collectors.toList()));
+	    model.addAttribute("outcomes", outcomes);
+	}
+
+	return "qb/stats";
+    }
+
+    private Integer getUserId() {
+	HttpSession ss = SessionManager.getSession();
+	UserDTO user = (UserDTO) ss.getAttribute(AttributeNames.USER);
+	return user != null ? user.getUserID() : null;
+    }
 }
\ No newline at end of file
Index: lams_central/web/qb/stats.jsp
===================================================================
diff -u -r4cea4e785c1ece3773109846b5bf78d25b0240d2 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_central/web/qb/stats.jsp	(.../stats.jsp)	(revision 4cea4e785c1ece3773109846b5bf78d25b0240d2)
+++ lams_central/web/qb/stats.jsp	(.../stats.jsp)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -58,8 +58,8 @@
 	<script type="text/javascript" src="<lams:LAMSURL/>includes/javascript/bootstrap.min.js"></script>
 	<script type="text/javascript" src="<lams:LAMSURL/>includes/javascript/thickbox.js"></script>
 	<script type="text/javascript">
-		var permanentRemove = ${permanentRemove},
-			permanentRemovePossible = ${permanentRemovePossible},
+		var permanentRemove = '${permanentRemove}' == 'true',
+			permanentRemovePossible = '${permanentRemovePossible}' == 'true',
 			optionsExist = ${not empty question.qbOptions};
 		
 		$(document).ready(function(){
@@ -453,8 +453,47 @@
 		</div>
 	</div>
 	
-	<lams:OutcomeAuthor qbQuestionId="${question.questionId}" />
-	
+	<c:choose>
+		<c:when test="${managementAllowed}">
+			<lams:OutcomeAuthor qbQuestionId="${question.questionId}" />
+		</c:when>
+		<c:otherwise>
+			<div class="panel panel-default">
+				<div class="panel-heading">
+					Learning outcomes
+				</div>
+				<div class="panel-body">
+					<c:choose>
+						<c:when test="${empty outcomes}">
+							This question does not have any learning outcomes
+						</c:when>
+						<c:otherwise>
+							<div class="container-fluid">			
+								<div class="row">
+									<div class="col-xs-0 col-md-2"></div>
+									<div class="col-xs-12 col-md-8 header-column">
+										Existing outcomes
+									</div>
+									<div class="col-xs-0 col-md-2"></div>
+								</div>
+								
+								<c:forEach var="outcome" items="${outcomes}">
+									<div class="row">
+										<div class="col-xs-0 col-md-2"></div>
+										<div class="col-xs-12 col-md-8 middle-cell">
+											<c:out value="${outcome}" />
+										</div>
+										<div class="col-xs-0 col-md-2">
+										</div>
+									</div>
+								</c:forEach>
+							</div>
+						</c:otherwise>
+					</c:choose>
+				</div>
+			</div>
+		</c:otherwise>
+	</c:choose>
 </lams:Page>
 
 <!-- For exporting QTI packages -->
Index: lams_common/src/java/org/lamsfoundation/lams/outcome/service/OutcomeService.java
===================================================================
diff -u -r67db3e1b2ada0d59ff98c807a54282783797c5e6 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_common/src/java/org/lamsfoundation/lams/outcome/service/OutcomeService.java	(.../OutcomeService.java)	(revision 67db3e1b2ada0d59ff98c807a54282783797c5e6)
+++ lams_common/src/java/org/lamsfoundation/lams/outcome/service/OutcomeService.java	(.../OutcomeService.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -1,8 +1,11 @@
 package org.lamsfoundation.lams.outcome.service;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.List;
@@ -292,6 +295,33 @@
 	return counter;
     }
 
+    /**
+     * There can be duplicates in mappings, if one comes from activity and the other comes from a QB question that the
+     * activity imported.
+     * We need to get rid of duplicates and sort the remaining mappings.
+     */
+    public static void filterQuestionMappings(List<OutcomeMapping> mappings) {
+	Iterator<OutcomeMapping> iterator = mappings.iterator();
+	while (iterator.hasNext()) {
+	    OutcomeMapping mapping = iterator.next();
+	    boolean duplicateFound = false;
+	    for (OutcomeMapping otherMapping : mappings) {
+		if (!mapping.getMappingId().equals(otherMapping.getMappingId())
+			&& mapping.getOutcome().getOutcomeId().equals(otherMapping.getOutcome().getOutcomeId())) {
+		    duplicateFound = true;
+		    break;
+		}
+	    }
+	    // remove the one coming from activity, not one coming from question
+	    if (duplicateFound && mapping.getQbQuestionId() == null) {
+		iterator.remove();
+	    }
+	}
+
+	Collections.sort(mappings,
+		Comparator.comparing(OutcomeMapping::getOutcome, Comparator.comparing(Outcome::getName)));
+    }
+
     private static UserDTO getUserDTO() {
 	HttpSession ss = SessionManager.getSession();
 	return (UserDTO) ss.getAttribute(AttributeNames.USER);
Index: lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java
===================================================================
diff -u -r67db3e1b2ada0d59ff98c807a54282783797c5e6 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java	(.../IQbDAO.java)	(revision 67db3e1b2ada0d59ff98c807a54282783797c5e6)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java	(.../IQbDAO.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -23,17 +23,17 @@
      * @return questions sharing the same questionId
      */
     List<QbQuestion> getQuestionsByQuestionId(Integer questionId);
-    
+
     List<QbQuestion> getQuestionsByToolContentId(long toolContentId);
-    
+
     // finds next question ID for Question Bank question
     int getMaxQuestionId();
 
     // finds next version for given question ID for Question Bank question
     int getMaxQuestionVersion(Integer qbQuestionId);
 
     List<ToolActivity> getQuestionActivities(long qbQuestionUid);
-    
+
     int getCountQuestionActivitiesByUid(long qbQuestionUid);
 
     int getCountQuestionActivitiesByQuestionId(int qbQuestionId);
@@ -68,4 +68,5 @@
 
     Set<Integer> getCollectionQuestionIdsExcluded(long collectionUid, Collection<Integer> qbQuestionIds);
 
+    boolean isQuestionInUserCollection(int userId, int qbQuestionId);
 }
\ No newline at end of file
Index: lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java
===================================================================
diff -u -r67db3e1b2ada0d59ff98c807a54282783797c5e6 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java	(.../QbDAO.java)	(revision 67db3e1b2ada0d59ff98c807a54282783797c5e6)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java	(.../QbDAO.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -85,6 +85,10 @@
     private static final String FIND_QUESTIONS_BY_TOOL_CONTENT_ID = "SELECT tq.qbQuestion FROM QbToolQuestion AS tq "
 	    + "WHERE tq.toolContentId = :toolContentId";
 
+    private static final String IS_QUESTION_IN_USER_COLLECTION = "SELECT DISTINCT 1 FROM lams_qb_collection_question AS cq "
+	    + "JOIN lams_qb_collection AS c ON cq.collection_uid = c.uid AND "
+	    + "(c.user_id = :userId OR c.user_id IS NULL) AND cq.qb_question_id = :qbQuestionId";
+
     @Override
     public QbQuestion getQuestionByUid(Long qbQuestionUid) {
 	return this.find(QbQuestion.class, qbQuestionUid);
@@ -338,6 +342,12 @@
 	return result;
     }
 
+    @Override
+    public boolean isQuestionInUserCollection(int userId, int qbQuestionId) {
+	return getSession().createNativeQuery(IS_QUESTION_IN_USER_COLLECTION).setParameter("userId", userId)
+		.setParameter("qbQuestionId", qbQuestionId).getSingleResult() != null;
+    }
+
     private boolean questionInCollectionExists(long collectionUid, int qbQuestionId) {
 	return !getSession().createNativeQuery(EXISTS_COLLECTION_QUESTION).setParameter("collectionUid", collectionUid)
 		.setParameter("qbQuestionId", qbQuestionId).getResultList().isEmpty();
Index: lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java
===================================================================
diff -u -r0b1e74374b821758fdda7835d8d283bf84fa8db0 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java	(.../IQbService.java)	(revision 0b1e74374b821758fdda7835d8d283bf84fa8db0)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java	(.../IQbService.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -1,131 +1,133 @@
-package org.lamsfoundation.lams.qb.service;
-
-import java.util.Collection;
-import java.util.List;
-
-import org.lamsfoundation.lams.qb.dto.QbStatsActivityDTO;
-import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
-import org.lamsfoundation.lams.qb.model.QbCollection;
-import org.lamsfoundation.lams.qb.model.QbOption;
-import org.lamsfoundation.lams.qb.model.QbQuestion;
-import org.lamsfoundation.lams.qb.model.QbQuestionUnit;
-import org.lamsfoundation.lams.usermanagement.Organisation;
-
-public interface IQbService {
-
-    // statuses of comparing QB question coming from authoring with data existing in DB
-
-    // no change detected
-    static final int QUESTION_MODIFIED_NONE = 0;
-    // change is minor, so the original question will be modified
-    static final int QUESTION_MODIFIED_UPDATE = 1;
-    // it is a new version of the old question
-    static final int QUESTION_MODIFIED_VERSION_BUMP = 2;
-    // it is a new question
-    static final int QUESTION_MODIFIED_ID_BUMP = 3;
-
-    /**
-     * @param qbQuestionUid
-     * @return QbQuestion object with the specified uid
-     */
-    QbQuestion getQuestionByUid(Long qbQuestionUid);
-
-    /**
-     * @param questionId
-     * @return questions sharing the same questionId
-     */
-    List<QbQuestion> getQuestionsByQuestionId(Integer questionId);
-
-    /**
-     * @param optionUid
-     * @return QbOption by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
-     */
-    QbOption getOptionByUid(Long optionUid);
-
-    /**
-     * @param unitUid
-     * @return QbQuestionUnit by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
-     */
-    QbQuestionUnit getQuestionUnitByUid(Long unitUid);
-
-    // finds next question ID for Question Bank question
-    int getMaxQuestionId();
-
-    // finds next version for given question ID for Question Bank question
-    int getMaxQuestionVersion(Integer qbQuestionId);
-
-    QbStatsDTO getQuestionStats(long qbQuestionUid);
-
-    int countQuestionVersions(int qbQuestionId);
-
-    QbStatsActivityDTO getActivityStatsByContentId(Long toolContentId, Long qbQuestionUid);
-
-    QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid);
-
-    QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid, Collection<Long> correctOptionUids);
-
-    List<QbQuestion> getPagedQuestions(Integer questionType, int page, int size, String sortBy, String sortOrder,
-	    String searchString);
-
-    int getCountQuestions(Integer questionType, String searchString);
-
-    QbCollection getCollectionByUid(Long collectionUid);
-
-    QbCollection getPublicCollection();
-
-    QbCollection getUserPrivateCollection(int userId);
-
-    List<QbCollection> getUserCollections(int userId);
-
-    List<QbCollection> getUserOwnCollections(int userId);
-
-    List<QbQuestion> getCollectionQuestions(long collectionUid);
-
-    List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
-	    String orderDirection, String search);
-
-    int getCountCollectionQuestions(long collectionUid, String search);
-
-    List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid);
-
-    List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId);
-
-    QbCollection addCollection(int userId, String name);
-
-    void removeCollection(long collectionUid);
-
-    List<Organisation> getShareableWithOrganisations(long collectionUid, int userId);
-
-    Organisation shareCollection(long collectionUid, int organisationId);
-
-    void unshareCollection(long collectionUid, int organisationId);
-
-    void addQuestionToCollection(long collectionUid, int qbQuestionUid, boolean copy);
-
-    void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
-	    Collection<Integer> excludedQbQuestionIds, boolean copy);
-
-    boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid);
-
-    boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId);
-
-    Collection<Integer> removeQuestionFromCollection(long collectionUid, Collection<Integer> excludedQbQuestionIds);
-
-    boolean removeQuestionByUid(long qbQuestionUid);
-
-    boolean removeQuestionByQuestionId(int qbQuestionId);
-
-    boolean removeQuestionPossibleByUid(long qbQuestionUid);
-
-    boolean removeQuestionPossibleByQuestionId(int qbQuestionId);
-
-    QbCollection getCollection(long collectionUid);
-
-    int getCountQuestionActivitiesByUid(long qbQuestionUid);
-
-    int getCountQuestionActivitiesByQuestionId(int qbQuestionId);
-
-    void changeCollectionName(long collectionUid, String name);
-
-    void releaseFromCache(Object object);
-}
+package org.lamsfoundation.lams.qb.service;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.lamsfoundation.lams.qb.dto.QbStatsActivityDTO;
+import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
+import org.lamsfoundation.lams.qb.model.QbCollection;
+import org.lamsfoundation.lams.qb.model.QbOption;
+import org.lamsfoundation.lams.qb.model.QbQuestion;
+import org.lamsfoundation.lams.qb.model.QbQuestionUnit;
+import org.lamsfoundation.lams.usermanagement.Organisation;
+
+public interface IQbService {
+
+    // statuses of comparing QB question coming from authoring with data existing in DB
+
+    // no change detected
+    static final int QUESTION_MODIFIED_NONE = 0;
+    // change is minor, so the original question will be modified
+    static final int QUESTION_MODIFIED_UPDATE = 1;
+    // it is a new version of the old question
+    static final int QUESTION_MODIFIED_VERSION_BUMP = 2;
+    // it is a new question
+    static final int QUESTION_MODIFIED_ID_BUMP = 3;
+
+    /**
+     * @param qbQuestionUid
+     * @return QbQuestion object with the specified uid
+     */
+    QbQuestion getQuestionByUid(Long qbQuestionUid);
+
+    /**
+     * @param questionId
+     * @return questions sharing the same questionId
+     */
+    List<QbQuestion> getQuestionsByQuestionId(Integer questionId);
+
+    /**
+     * @param optionUid
+     * @return QbOption by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
+     */
+    QbOption getOptionByUid(Long optionUid);
+
+    /**
+     * @param unitUid
+     * @return QbQuestionUnit by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
+     */
+    QbQuestionUnit getQuestionUnitByUid(Long unitUid);
+
+    // finds next question ID for Question Bank question
+    int getMaxQuestionId();
+
+    // finds next version for given question ID for Question Bank question
+    int getMaxQuestionVersion(Integer qbQuestionId);
+
+    QbStatsDTO getQuestionStats(long qbQuestionUid);
+
+    int countQuestionVersions(int qbQuestionId);
+
+    QbStatsActivityDTO getActivityStatsByContentId(Long toolContentId, Long qbQuestionUid);
+
+    QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid);
+
+    QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid, Collection<Long> correctOptionUids);
+
+    List<QbQuestion> getPagedQuestions(Integer questionType, int page, int size, String sortBy, String sortOrder,
+	    String searchString);
+
+    int getCountQuestions(Integer questionType, String searchString);
+
+    QbCollection getCollectionByUid(Long collectionUid);
+
+    QbCollection getPublicCollection();
+
+    QbCollection getUserPrivateCollection(int userId);
+
+    List<QbCollection> getUserCollections(int userId);
+
+    List<QbCollection> getUserOwnCollections(int userId);
+
+    List<QbQuestion> getCollectionQuestions(long collectionUid);
+
+    List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
+	    String orderDirection, String search);
+
+    int getCountCollectionQuestions(long collectionUid, String search);
+
+    List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid);
+
+    List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId);
+
+    QbCollection addCollection(int userId, String name);
+
+    void removeCollection(long collectionUid);
+
+    List<Organisation> getShareableWithOrganisations(long collectionUid, int userId);
+
+    Organisation shareCollection(long collectionUid, int organisationId);
+
+    void unshareCollection(long collectionUid, int organisationId);
+
+    void addQuestionToCollection(long collectionUid, int qbQuestionUid, boolean copy);
+
+    void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
+	    Collection<Integer> excludedQbQuestionIds, boolean copy);
+
+    boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid);
+
+    boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId);
+
+    Collection<Integer> removeQuestionFromCollection(long collectionUid, Collection<Integer> excludedQbQuestionIds);
+
+    boolean removeQuestionByUid(long qbQuestionUid);
+
+    boolean removeQuestionByQuestionId(int qbQuestionId);
+
+    boolean removeQuestionPossibleByUid(long qbQuestionUid);
+
+    boolean removeQuestionPossibleByQuestionId(int qbQuestionId);
+
+    QbCollection getCollection(long collectionUid);
+
+    int getCountQuestionActivitiesByUid(long qbQuestionUid);
+
+    int getCountQuestionActivitiesByQuestionId(int qbQuestionId);
+
+    void changeCollectionName(long collectionUid, String name);
+
+    void releaseFromCache(Object object);
+
+    boolean isQuestionInUserCollection(int qbQuestionId, int userId);
+}
Index: lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java
===================================================================
diff -u -r0b1e74374b821758fdda7835d8d283bf84fa8db0 -r0f2b554d8e5dca78a8e936730490d03ecd0357ba
--- lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision 0b1e74374b821758fdda7835d8d283bf84fa8db0)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision 0f2b554d8e5dca78a8e936730490d03ecd0357ba)
@@ -1,567 +1,572 @@
-package org.lamsfoundation.lams.qb.service;
-
-import java.security.InvalidParameterException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Date;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.Set;
-
-import org.apache.log4j.Logger;
-import org.lamsfoundation.lams.gradebook.GradebookUserLesson;
-import org.lamsfoundation.lams.gradebook.service.IGradebookService;
-import org.lamsfoundation.lams.learningdesign.Activity;
-import org.lamsfoundation.lams.learningdesign.LearningDesign;
-import org.lamsfoundation.lams.learningdesign.ToolActivity;
-import org.lamsfoundation.lams.lesson.Lesson;
-import org.lamsfoundation.lams.qb.dao.IQbDAO;
-import org.lamsfoundation.lams.qb.dto.QbStatsActivityDTO;
-import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
-import org.lamsfoundation.lams.qb.model.QbCollection;
-import org.lamsfoundation.lams.qb.model.QbOption;
-import org.lamsfoundation.lams.qb.model.QbQuestion;
-import org.lamsfoundation.lams.qb.model.QbQuestionUnit;
-import org.lamsfoundation.lams.qb.model.QbToolQuestion;
-import org.lamsfoundation.lams.tool.service.ILamsCoreToolService;
-import org.lamsfoundation.lams.usermanagement.Organisation;
-import org.lamsfoundation.lams.usermanagement.Role;
-import org.lamsfoundation.lams.usermanagement.service.IUserManagementService;
-import org.lamsfoundation.lams.util.Configuration;
-import org.lamsfoundation.lams.util.ConfigurationKeys;
-import org.lamsfoundation.lams.util.WebUtil;
-
-import com.fasterxml.jackson.databind.node.ArrayNode;
-import com.fasterxml.jackson.databind.node.JsonNodeFactory;
-import com.fasterxml.jackson.databind.node.ObjectNode;
-
-public class QbService implements IQbService {
-    private static Logger log = Logger.getLogger(QbService.class);
-
-    private IQbDAO qbDAO;
-
-    private IGradebookService gradebookService;
-
-    private ILamsCoreToolService lamsCoreToolService;
-
-    private IUserManagementService userManagementService;
-
-    public static final Comparator<QbCollection> COLLECTION_NAME_COMPARATOR = Comparator
-	    .comparing(QbCollection::getName);
-
-    @Override
-    public QbQuestion getQuestionByUid(Long qbQuestionUid) {
-	return qbDAO.getQuestionByUid(qbQuestionUid);
-    }
-
-    @Override
-    public List<QbQuestion> getQuestionsByQuestionId(Integer questionId) {
-	return qbDAO.getQuestionsByQuestionId(questionId);
-    }
-
-    @Override
-    public QbOption getOptionByUid(Long optionUid) {
-	QbOption option = qbDAO.find(QbOption.class, optionUid);
-	qbDAO.releaseFromCache(option);
-	qbDAO.releaseFromCache(option.getQbQuestion());
-	return option;
-    }
-
-    @Override
-    public QbQuestionUnit getQuestionUnitByUid(Long unitUid) {
-	QbQuestionUnit unit = qbDAO.find(QbQuestionUnit.class, unitUid);
-	qbDAO.releaseFromCache(unit);
-	qbDAO.releaseFromCache(unit.getQbQuestion());
-	return unit;
-    }
-
-    @Override
-    public int getMaxQuestionId() {
-	return qbDAO.getMaxQuestionId();
-    }
-
-    @Override
-    public int getMaxQuestionVersion(Integer qbQuestionId) {
-	return qbDAO.getMaxQuestionVersion(qbQuestionId);
-    }
-
-    @Override
-    public List<QbQuestion> getPagedQuestions(Integer questionType, int page, int size, String sortBy, String sortOrder,
-	    String searchString) {
-	return qbDAO.getPagedQuestions(questionType, page, size, sortBy, sortOrder, searchString);
-    }
-
-    @Override
-    public int getCountQuestions(Integer questionType, String searchString) {
-	return qbDAO.getCountQuestions(questionType, searchString);
-    }
-
-    @Override
-    public QbStatsDTO getQuestionStats(long qbQuestionUid) {
-	QbStatsDTO stats = new QbStatsDTO();
-	QbQuestion qbQuestion = qbDAO.find(QbQuestion.class, qbQuestionUid);
-	List<QbOption> qbOptions = qbQuestion.getQbOptions();
-	stats.setQuestion(qbQuestion);
-	Map<String, Long> burningQuestions = qbDAO.getBurningQuestions(qbQuestionUid);
-	stats.setBurningQuestions(burningQuestions);
-
-	List<ToolActivity> activities = qbDAO.getQuestionActivities(qbQuestionUid);
-	List<QbStatsActivityDTO> activityDTOs = new LinkedList<>();
-
-	Set<Long> correctOptionUids = new HashSet<>();
-	for (QbOption option : qbOptions) {
-	    if (option.isCorrect()) {
-		correctOptionUids.add(option.getUid());
-	    }
-	}
-	// calculate correct answer average for each activity
-	for (ToolActivity activity : activities) {
-	    QbStatsActivityDTO activityDTO = getActivityStats(activity.getActivityId(), qbQuestionUid,
-		    correctOptionUids);
-	    activityDTOs.add(activityDTO);
-	}
-	stats.setActivities(activityDTOs);
-
-	stats.setVersions(qbDAO.getQuestionVersions(qbQuestionUid));
-	Map<Long, Long> answersRaw = qbDAO.getAnswerStatsForQuestion(qbQuestionUid);
-	stats.setAnswersRaw(answersRaw);
-
-	ArrayNode answersJSON = JsonNodeFactory.instance.arrayNode();
-	double total = 0;
-	for (Long answerCount : answersRaw.values()) {
-	    total += answerCount;
-	}
-	Map<Long, Integer> answerPercent = new HashMap<>();
-	for (int answerIndex = 0; answerIndex < qbOptions.size(); answerIndex++) {
-	    QbOption option = qbOptions.get(answerIndex);
-	    Long answerCount = answersRaw.get(option.getUid());
-	    int value = answerCount == null ? 0 : Long.valueOf(Math.round(answerCount / total * 100)).intValue();
-	    answerPercent.put(option.getUid(), value);
-
-	    ObjectNode answerJSON = JsonNodeFactory.instance.objectNode();
-	    String name = WebUtil.removeHTMLtags(option.getName());
-	    name = (answerIndex + 1) + ". " + (name.length() > 30 ? name.substring(0, 30) + "..." : name);
-	    answerJSON.put("name", name);
-	    answerJSON.put("value", value);
-	    answersJSON.add(answerJSON);
-	}
-	stats.setAnswersPercent(answerPercent);
-	stats.setAnswersJSON(answersJSON.toString());
-	return stats;
-    }
-
-    @Override
-    public int countQuestionVersions(int qbQuestionId) {
-	Map<String, Object> properties = new HashMap<>();
-	properties.put("questionId", qbQuestionId);
-	return Long.valueOf(qbDAO.countByProperties(QbQuestion.class, properties)).intValue();
-    }
-
-    @Override
-    public QbStatsActivityDTO getActivityStatsByContentId(Long toolContentId, Long qbQuestionUid) {
-	Activity activity = qbDAO.findByProperty(ToolActivity.class, "toolContentId", toolContentId).get(0);
-	return getActivityStats(activity.getActivityId(), qbQuestionUid);
-    }
-
-    @Override
-    public QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid) {
-	QbQuestion qbQuestion = qbDAO.find(QbQuestion.class, qbQuestionUid);
-	Set<Long> correctOptionUids = new HashSet<>();
-	for (QbOption option : qbQuestion.getQbOptions()) {
-	    if (option.isCorrect()) {
-		correctOptionUids.add(option.getUid());
-	    }
-	}
-	return getActivityStats(activityId, qbQuestionUid, correctOptionUids);
-    }
-
-    @Override
-    public QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid,
-	    Collection<Long> correctOptionUids) {
-	ToolActivity activity = qbDAO.find(ToolActivity.class, activityId);
-	LearningDesign learningDesign = activity.getLearningDesign();
-	Lesson lesson = learningDesign.getLessons().iterator().next();
-	Long lessonId = lesson.getLessonId();
-	List<GradebookUserLesson> userLessonGrades = gradebookService.getGradebookUserLesson(lessonId);
-	int participantCount = userLessonGrades.size();
-
-	QbStatsActivityDTO activityDTO = new QbStatsActivityDTO();
-	activityDTO.setActivity(activity);
-	activityDTO.setParticipantCount(participantCount);
-
-	String monitorUrl = "/lams/" + lamsCoreToolService.getToolMonitoringURL(lessonId, activity)
-		+ "&contentFolderID=" + learningDesign.getContentFolderID();
-	activityDTO.setMonitorURL(monitorUrl);
-
-	// if there is only 1 participant, there is no point in calculating question indexes
-	if (participantCount >= Configuration.getAsInt(ConfigurationKeys.QB_STATS_MIN_PARTICIPANTS)) {
-	    // mapping of user ID -> option UID
-	    Map<Integer, Long> activityAnswers = qbDAO.getAnswersForActivity(activity.getActivityId(), qbQuestionUid);
-	    // see who answered correctly
-	    Set<Integer> correctUserIds = new HashSet<>();
-	    for (Entry<Integer, Long> answer : activityAnswers.entrySet()) {
-		Integer userId = answer.getKey();
-		Long optionUid = answer.getValue();
-		if (correctOptionUids.contains(optionUid)) {
-		    correctUserIds.add(userId);
-		}
-	    }
-
-	    int correctUserCount = correctUserIds.size();
-	    int incorrectUserCount = participantCount - correctUserCount;
-	    int topUsersCorrect = 0;
-	    int bottomUsersCorrect = 0;
-	    double allUserMarkSum = 0;
-	    double correctUserMarkSum = 0;
-	    double incorrectUserMarkSum = 0;
-
-	    // sort grades by highest mark
-	    Collections.sort(userLessonGrades, (a, b) -> a.getMark().compareTo(b.getMark()));
-	    // see how many learners should be in top/bottom 27% of the group
-	    int groupCount = (int) Math.ceil(
-		    Configuration.getAsInt(ConfigurationKeys.QB_STATS_MIN_PARTICIPANTS) / 100.0 * participantCount);
-
-	    // go through each grade and gather data for indexes
-	    for (int userIndex = 0; userIndex < participantCount; userIndex++) {
-		GradebookUserLesson grade = userLessonGrades.get(userIndex);
-		double mark = grade.getMark();
-		allUserMarkSum += mark;
-		boolean isCorrect = correctUserIds.contains(grade.getLearner().getUserId());
-		if (isCorrect) {
-		    correctUserMarkSum += mark;
-		    if (userIndex < groupCount) {
-			topUsersCorrect++;
-		    } else if (userIndex >= participantCount - groupCount) {
-			bottomUsersCorrect++;
-		    }
-		} else {
-		    incorrectUserMarkSum += mark;
-		}
-	    }
-
-	    // calculate standard deviation needed for point biserial
-	    double deviation = 0;
-	    double markAverage = allUserMarkSum / participantCount;
-	    for (int userIndex = 0; userIndex < participantCount; userIndex++) {
-		GradebookUserLesson grade = userLessonGrades.get(userIndex);
-		double mark = grade.getMark();
-		deviation += Math.pow(mark - markAverage, 2);
-	    }
-	    deviation = Math.sqrt(deviation / participantCount);
-
-	    activityDTO.setDifficultyIndex(participantCount == 0 ? null : (double) correctUserCount / participantCount);
-	    activityDTO.setDiscriminationIndex((double) (topUsersCorrect - bottomUsersCorrect) / groupCount);
-	    if (correctUserCount == 0 || incorrectUserCount == 0) {
-		activityDTO.setPointBiserial(0d);
-	    } else {
-		activityDTO.setPointBiserial(
-			(correctUserMarkSum / correctUserCount - incorrectUserMarkSum / incorrectUserCount) / deviation
-				* Math.sqrt(correctUserCount * incorrectUserCount / Math.pow(participantCount, 2)));
-	    }
-	}
-
-	return activityDTO;
-    }
-
-    @Override
-    public QbCollection getCollectionByUid(Long collectionUid) {
-	return qbDAO.find(QbCollection.class, collectionUid);
-    }
-
-    @Override
-    public QbCollection getPublicCollection() {
-	return qbDAO.find(QbCollection.class, 1L);
-    }
-
-    @Override
-    public QbCollection getUserPrivateCollection(int userId) {
-	Map<String, Object> map = new HashMap<>();
-	map.put("userId", userId);
-	map.put("personal", true);
-	List<QbCollection> result = qbDAO.findByProperties(QbCollection.class, map);
-	if (!result.isEmpty()) {
-	    return result.get(0);
-	}
-
-	// is an user does not have a private collection yet, create it
-	QbCollection collection = new QbCollection();
-	collection.setName("My questions");
-	collection.setUserId(userId);
-	collection.setPersonal(true);
-	qbDAO.insert(collection);
-	return collection;
-    }
-
-    @Override
-    public List<QbCollection> getUserOwnCollections(int userId) {
-	Map<String, Object> map = new HashMap<>();
-	map.put("userId", userId);
-	map.put("personal", false);
-	List<QbCollection> result = qbDAO.findByProperties(QbCollection.class, map);
-	Collections.sort(result, COLLECTION_NAME_COMPARATOR);
-	return result;
-    }
-
-    @Override
-    public List<QbQuestion> getCollectionQuestions(long collectionUid) {
-	return qbDAO.getCollectionQuestions(collectionUid);
-    }
-
-    @Override
-    public List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
-	    String orderDirection, String search) {
-	return qbDAO.getCollectionQuestions(collectionUid, offset, limit, orderBy, orderDirection, search);
-    }
-
-    @Override
-    public int getCountCollectionQuestions(long collectionUid, String search) {
-	return qbDAO.getCountCollectionQuestions(collectionUid, search);
-    }
-
-    @Override
-    public List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid) {
-	return qbDAO.getQuestionCollectionsByUid(qbQuestionUid);
-    }
-
-    @Override
-    public List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId) {
-	return qbDAO.getQuestionCollectionsByQuestionId(qbQuestionId);
-    }
-
-    @Override
-    public QbCollection addCollection(int userId, String name) {
-	QbCollection collection = new QbCollection();
-	collection.setName(name);
-	collection.setUserId(userId);
-	qbDAO.insert(collection);
-	return collection;
-    }
-
-    @Override
-    public void removeCollection(long collectionUid) {
-	if (getCountCollectionQuestions(collectionUid, null) > 0) {
-	    throw new InvalidParameterException("Can not remove a collection with questions");
-	}
-	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
-	if (collection.getUserId() == null || collection.isPersonal()) {
-	    throw new InvalidParameterException("Attempt to remove a private or the public question bank collection");
-	}
-	qbDAO.delete(collection);
-    }
-
-    @Override
-    public boolean removeQuestionByUid(long qbQuestionUid) {
-	boolean removeQuestionPossible = removeQuestionPossibleByUid(qbQuestionUid);
-	if (!removeQuestionPossible) {
-	    // if the question is used in a Learning Design, do not allow to remove it
-	    return false;
-	}
-	qbDAO.deleteById(QbQuestion.class, qbQuestionUid);
-	return true;
-    }
-
-    @Override
-    public boolean removeQuestionByQuestionId(int qbQuestionId) {
-	boolean removeQuestionPossible = removeQuestionPossibleByQuestionId(qbQuestionId);
-	if (!removeQuestionPossible) {
-	    // if the question is used in a Learning Design, do not allow to remove it
-	    return false;
-	}
-	Map<String, Object> properties = new HashMap<>();
-	properties.put("questionId", qbQuestionId);
-	qbDAO.deleteByProperties(QbQuestion.class, properties);
-	return true;
-    }
-
-    @Override
-    public boolean removeQuestionPossibleByUid(long qbQuestionUid) {
-	Map<String, Object> properties = new HashMap<>();
-	properties.put("qbQuestion.uid", qbQuestionUid);
-	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
-    }
-
-    @Override
-    public boolean removeQuestionPossibleByQuestionId(int qbQuestionId) {
-	Map<String, Object> properties = new HashMap<>();
-	properties.put("qbQuestion.questionId", qbQuestionId);
-	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
-    }
-
-    @Override
-    public Organisation shareCollection(long collectionUid, int organisationId) {
-	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
-	if (collection.getUserId() == null || collection.isPersonal()) {
-	    throw new InvalidParameterException("Attempt to share a private or the public question bank collection");
-	}
-	Organisation organisation = qbDAO.find(Organisation.class, organisationId);
-	collection.getOrganisations().add(organisation);
-	qbDAO.update(collection);
-	return organisation;
-    }
-
-    @Override
-    public void unshareCollection(long collectionUid, int organisationId) {
-	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
-	if (collection.getUserId() == null || collection.isPersonal()) {
-	    throw new InvalidParameterException("Attempt to unshare a private or the public question bank collection");
-	}
-	Iterator<Organisation> orgIterator = collection.getOrganisations().iterator();
-	while (orgIterator.hasNext()) {
-	    if (orgIterator.next().getOrganisationId().equals(organisationId)) {
-		orgIterator.remove();
-		break;
-	    }
-	}
-	qbDAO.update(collection);
-    }
-
-    @Override
-    public void addQuestionToCollection(long collectionUid, int qbQuestionId, boolean copy) {
-	int addQbQuestionId = qbQuestionId;
-	if (copy) {
-	    List<QbQuestion> questions = getQuestionsByQuestionId(qbQuestionId);
-	    QbQuestion question = questions.get(0);
-	    QbQuestion newQuestion = question.clone();
-	    addQbQuestionId = getMaxQuestionId();
-	    newQuestion.setQuestionId(addQbQuestionId);
-	    newQuestion.setVersion(1);
-	    newQuestion.setCreateDate(new Date());
-	    newQuestion.clearID();
-	    qbDAO.insert(newQuestion);
-	}
-	qbDAO.addCollectionQuestion(collectionUid, addQbQuestionId);
-    }
-
-    @Override
-    public void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
-	    Collection<Integer> excludedQbQuestionIds, boolean copy) {
-	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(sourceCollectionUid,
-		excludedQbQuestionIds);
-	for (Integer questionId : includedIds) {
-	    addQuestionToCollection(targetCollectionUid, questionId, copy);
-	}
-    }
-
-    @Override
-    public boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid) {
-	QbQuestion question = getQuestionByUid(qbQuestionUid);
-	return removeQuestionFromCollectionByQuestionId(collectionUid, question.getQuestionId());
-    }
-
-    @Override
-    public boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId) {
-	Collection<QbCollection> collections = getQuestionCollectionsByQuestionId(qbQuestionId);
-	int size = collections.size();
-	if (size <= 1) {
-	    // if the question is in its last collection, try to remove it permanently
-	    return removeQuestionByQuestionId(qbQuestionId);
-	}
-	qbDAO.removeCollectionQuestion(collectionUid, qbQuestionId);
-	return true;
-    }
-
-    @Override
-    public Collection<Integer> removeQuestionFromCollection(long collectionUid,
-	    Collection<Integer> excludedQbQuestionIds) {
-	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(collectionUid, excludedQbQuestionIds);
-	Collection<Integer> retainedQuestionIds = new HashSet<>();
-	for (Integer questionId : includedIds) {
-	    boolean deleted = removeQuestionFromCollectionByQuestionId(collectionUid, questionId);
-	    if (!deleted) {
-		retainedQuestionIds.add(questionId);
-	    }
-	}
-	return retainedQuestionIds;
-    }
-
-    @Override
-    public List<Organisation> getShareableWithOrganisations(long collectionUid, int userId) {
-	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
-	if (collection.getUserId() == null || collection.isPersonal()) {
-	    return null;
-	}
-
-	List<Organisation> result = new ArrayList<>();
-	Map<Integer, Set<Integer>> roles = userManagementService.getRolesForUser(userId);
-	for (Entry<Integer, Set<Integer>> roleEntry : roles.entrySet()) {
-	    Integer organisationId = roleEntry.getKey();
-	    for (Organisation organisation : collection.getOrganisations()) {
-		if (organisation.getOrganisationId().equals(organisationId)) {
-		    organisationId = null;
-		    break;
-		}
-	    }
-	    if (organisationId != null && roleEntry.getValue().contains(Role.ROLE_AUTHOR)) {
-		Organisation organisation = qbDAO.find(Organisation.class, organisationId);
-		result.add(organisation);
-	    }
-	}
-
-	return result;
-    }
-
-    @Override
-    public void releaseFromCache(Object object) {
-	qbDAO.releaseFromCache(object);
-    }
-
-    @Override
-    public List<QbCollection> getUserCollections(int userId) {
-	List<QbCollection> collections = new LinkedList<>();
-
-	QbCollection privateCollection = getUserPrivateCollection(userId);
-	collections.add(privateCollection);
-
-	collections.addAll(getUserOwnCollections(userId));
-
-	QbCollection publicCollection = getPublicCollection();
-	collections.add(publicCollection);
-
-	return collections;
-    }
-
-    @Override
-    public QbCollection getCollection(long collectionUid) {
-	return qbDAO.find(QbCollection.class, collectionUid);
-    }
-
-    @Override
-    public int getCountQuestionActivitiesByUid(long qbQuestionUid) {
-	return qbDAO.getCountQuestionActivitiesByUid(qbQuestionUid);
-    }
-
-    @Override
-    public int getCountQuestionActivitiesByQuestionId(int qbQuestionId) {
-	return qbDAO.getCountQuestionActivitiesByQuestionId(qbQuestionId);
-    }
-
-    @Override
-    public void changeCollectionName(long collectionUid, String name) {
-	QbCollection collection = getCollection(collectionUid);
-	collection.setName(name);
-	qbDAO.update(collection);
-    }
-
-    public void setQbDAO(IQbDAO qbDAO) {
-	this.qbDAO = qbDAO;
-    }
-
-    public void setGradebookService(IGradebookService gradebookService) {
-	this.gradebookService = gradebookService;
-    }
-
-    public void setLamsCoreToolService(ILamsCoreToolService lamsCoreToolService) {
-	this.lamsCoreToolService = lamsCoreToolService;
-    }
-
-    public void setUserManagementService(IUserManagementService userManagementService) {
-	this.userManagementService = userManagementService;
-    }
+package org.lamsfoundation.lams.qb.service;
+
+import java.security.InvalidParameterException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.apache.log4j.Logger;
+import org.lamsfoundation.lams.gradebook.GradebookUserLesson;
+import org.lamsfoundation.lams.gradebook.service.IGradebookService;
+import org.lamsfoundation.lams.learningdesign.Activity;
+import org.lamsfoundation.lams.learningdesign.LearningDesign;
+import org.lamsfoundation.lams.learningdesign.ToolActivity;
+import org.lamsfoundation.lams.lesson.Lesson;
+import org.lamsfoundation.lams.qb.dao.IQbDAO;
+import org.lamsfoundation.lams.qb.dto.QbStatsActivityDTO;
+import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
+import org.lamsfoundation.lams.qb.model.QbCollection;
+import org.lamsfoundation.lams.qb.model.QbOption;
+import org.lamsfoundation.lams.qb.model.QbQuestion;
+import org.lamsfoundation.lams.qb.model.QbQuestionUnit;
+import org.lamsfoundation.lams.qb.model.QbToolQuestion;
+import org.lamsfoundation.lams.tool.service.ILamsCoreToolService;
+import org.lamsfoundation.lams.usermanagement.Organisation;
+import org.lamsfoundation.lams.usermanagement.Role;
+import org.lamsfoundation.lams.usermanagement.service.IUserManagementService;
+import org.lamsfoundation.lams.util.Configuration;
+import org.lamsfoundation.lams.util.ConfigurationKeys;
+import org.lamsfoundation.lams.util.WebUtil;
+
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+public class QbService implements IQbService {
+    private static Logger log = Logger.getLogger(QbService.class);
+
+    private IQbDAO qbDAO;
+
+    private IGradebookService gradebookService;
+
+    private ILamsCoreToolService lamsCoreToolService;
+
+    private IUserManagementService userManagementService;
+
+    public static final Comparator<QbCollection> COLLECTION_NAME_COMPARATOR = Comparator
+	    .comparing(QbCollection::getName);
+
+    @Override
+    public QbQuestion getQuestionByUid(Long qbQuestionUid) {
+	return qbDAO.getQuestionByUid(qbQuestionUid);
+    }
+
+    @Override
+    public List<QbQuestion> getQuestionsByQuestionId(Integer questionId) {
+	return qbDAO.getQuestionsByQuestionId(questionId);
+    }
+
+    @Override
+    public QbOption getOptionByUid(Long optionUid) {
+	QbOption option = qbDAO.find(QbOption.class, optionUid);
+	qbDAO.releaseFromCache(option);
+	qbDAO.releaseFromCache(option.getQbQuestion());
+	return option;
+    }
+
+    @Override
+    public QbQuestionUnit getQuestionUnitByUid(Long unitUid) {
+	QbQuestionUnit unit = qbDAO.find(QbQuestionUnit.class, unitUid);
+	qbDAO.releaseFromCache(unit);
+	qbDAO.releaseFromCache(unit.getQbQuestion());
+	return unit;
+    }
+
+    @Override
+    public int getMaxQuestionId() {
+	return qbDAO.getMaxQuestionId();
+    }
+
+    @Override
+    public int getMaxQuestionVersion(Integer qbQuestionId) {
+	return qbDAO.getMaxQuestionVersion(qbQuestionId);
+    }
+
+    @Override
+    public List<QbQuestion> getPagedQuestions(Integer questionType, int page, int size, String sortBy, String sortOrder,
+	    String searchString) {
+	return qbDAO.getPagedQuestions(questionType, page, size, sortBy, sortOrder, searchString);
+    }
+
+    @Override
+    public int getCountQuestions(Integer questionType, String searchString) {
+	return qbDAO.getCountQuestions(questionType, searchString);
+    }
+
+    @Override
+    public QbStatsDTO getQuestionStats(long qbQuestionUid) {
+	QbStatsDTO stats = new QbStatsDTO();
+	QbQuestion qbQuestion = qbDAO.find(QbQuestion.class, qbQuestionUid);
+	List<QbOption> qbOptions = qbQuestion.getQbOptions();
+	stats.setQuestion(qbQuestion);
+	Map<String, Long> burningQuestions = qbDAO.getBurningQuestions(qbQuestionUid);
+	stats.setBurningQuestions(burningQuestions);
+
+	List<ToolActivity> activities = qbDAO.getQuestionActivities(qbQuestionUid);
+	List<QbStatsActivityDTO> activityDTOs = new LinkedList<>();
+
+	Set<Long> correctOptionUids = new HashSet<>();
+	for (QbOption option : qbOptions) {
+	    if (option.isCorrect()) {
+		correctOptionUids.add(option.getUid());
+	    }
+	}
+	// calculate correct answer average for each activity
+	for (ToolActivity activity : activities) {
+	    QbStatsActivityDTO activityDTO = getActivityStats(activity.getActivityId(), qbQuestionUid,
+		    correctOptionUids);
+	    activityDTOs.add(activityDTO);
+	}
+	stats.setActivities(activityDTOs);
+
+	stats.setVersions(qbDAO.getQuestionVersions(qbQuestionUid));
+	Map<Long, Long> answersRaw = qbDAO.getAnswerStatsForQuestion(qbQuestionUid);
+	stats.setAnswersRaw(answersRaw);
+
+	ArrayNode answersJSON = JsonNodeFactory.instance.arrayNode();
+	double total = 0;
+	for (Long answerCount : answersRaw.values()) {
+	    total += answerCount;
+	}
+	Map<Long, Integer> answerPercent = new HashMap<>();
+	for (int answerIndex = 0; answerIndex < qbOptions.size(); answerIndex++) {
+	    QbOption option = qbOptions.get(answerIndex);
+	    Long answerCount = answersRaw.get(option.getUid());
+	    int value = answerCount == null ? 0 : Long.valueOf(Math.round(answerCount / total * 100)).intValue();
+	    answerPercent.put(option.getUid(), value);
+
+	    ObjectNode answerJSON = JsonNodeFactory.instance.objectNode();
+	    String name = WebUtil.removeHTMLtags(option.getName());
+	    name = (answerIndex + 1) + ". " + (name.length() > 30 ? name.substring(0, 30) + "..." : name);
+	    answerJSON.put("name", name);
+	    answerJSON.put("value", value);
+	    answersJSON.add(answerJSON);
+	}
+	stats.setAnswersPercent(answerPercent);
+	stats.setAnswersJSON(answersJSON.toString());
+	return stats;
+    }
+
+    @Override
+    public int countQuestionVersions(int qbQuestionId) {
+	Map<String, Object> properties = new HashMap<>();
+	properties.put("questionId", qbQuestionId);
+	return Long.valueOf(qbDAO.countByProperties(QbQuestion.class, properties)).intValue();
+    }
+
+    @Override
+    public QbStatsActivityDTO getActivityStatsByContentId(Long toolContentId, Long qbQuestionUid) {
+	Activity activity = qbDAO.findByProperty(ToolActivity.class, "toolContentId", toolContentId).get(0);
+	return getActivityStats(activity.getActivityId(), qbQuestionUid);
+    }
+
+    @Override
+    public QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid) {
+	QbQuestion qbQuestion = qbDAO.find(QbQuestion.class, qbQuestionUid);
+	Set<Long> correctOptionUids = new HashSet<>();
+	for (QbOption option : qbQuestion.getQbOptions()) {
+	    if (option.isCorrect()) {
+		correctOptionUids.add(option.getUid());
+	    }
+	}
+	return getActivityStats(activityId, qbQuestionUid, correctOptionUids);
+    }
+
+    @Override
+    public QbStatsActivityDTO getActivityStats(Long activityId, Long qbQuestionUid,
+	    Collection<Long> correctOptionUids) {
+	ToolActivity activity = qbDAO.find(ToolActivity.class, activityId);
+	LearningDesign learningDesign = activity.getLearningDesign();
+	Lesson lesson = learningDesign.getLessons().iterator().next();
+	Long lessonId = lesson.getLessonId();
+	List<GradebookUserLesson> userLessonGrades = gradebookService.getGradebookUserLesson(lessonId);
+	int participantCount = userLessonGrades.size();
+
+	QbStatsActivityDTO activityDTO = new QbStatsActivityDTO();
+	activityDTO.setActivity(activity);
+	activityDTO.setParticipantCount(participantCount);
+
+	String monitorUrl = "/lams/" + lamsCoreToolService.getToolMonitoringURL(lessonId, activity)
+		+ "&contentFolderID=" + learningDesign.getContentFolderID();
+	activityDTO.setMonitorURL(monitorUrl);
+
+	// if there is only 1 participant, there is no point in calculating question indexes
+	if (participantCount >= Configuration.getAsInt(ConfigurationKeys.QB_STATS_MIN_PARTICIPANTS)) {
+	    // mapping of user ID -> option UID
+	    Map<Integer, Long> activityAnswers = qbDAO.getAnswersForActivity(activity.getActivityId(), qbQuestionUid);
+	    // see who answered correctly
+	    Set<Integer> correctUserIds = new HashSet<>();
+	    for (Entry<Integer, Long> answer : activityAnswers.entrySet()) {
+		Integer userId = answer.getKey();
+		Long optionUid = answer.getValue();
+		if (correctOptionUids.contains(optionUid)) {
+		    correctUserIds.add(userId);
+		}
+	    }
+
+	    int correctUserCount = correctUserIds.size();
+	    int incorrectUserCount = participantCount - correctUserCount;
+	    int topUsersCorrect = 0;
+	    int bottomUsersCorrect = 0;
+	    double allUserMarkSum = 0;
+	    double correctUserMarkSum = 0;
+	    double incorrectUserMarkSum = 0;
+
+	    // sort grades by highest mark
+	    Collections.sort(userLessonGrades, (a, b) -> a.getMark().compareTo(b.getMark()));
+	    // see how many learners should be in top/bottom 27% of the group
+	    int groupCount = (int) Math.ceil(
+		    Configuration.getAsInt(ConfigurationKeys.QB_STATS_MIN_PARTICIPANTS) / 100.0 * participantCount);
+
+	    // go through each grade and gather data for indexes
+	    for (int userIndex = 0; userIndex < participantCount; userIndex++) {
+		GradebookUserLesson grade = userLessonGrades.get(userIndex);
+		double mark = grade.getMark();
+		allUserMarkSum += mark;
+		boolean isCorrect = correctUserIds.contains(grade.getLearner().getUserId());
+		if (isCorrect) {
+		    correctUserMarkSum += mark;
+		    if (userIndex < groupCount) {
+			topUsersCorrect++;
+		    } else if (userIndex >= participantCount - groupCount) {
+			bottomUsersCorrect++;
+		    }
+		} else {
+		    incorrectUserMarkSum += mark;
+		}
+	    }
+
+	    // calculate standard deviation needed for point biserial
+	    double deviation = 0;
+	    double markAverage = allUserMarkSum / participantCount;
+	    for (int userIndex = 0; userIndex < participantCount; userIndex++) {
+		GradebookUserLesson grade = userLessonGrades.get(userIndex);
+		double mark = grade.getMark();
+		deviation += Math.pow(mark - markAverage, 2);
+	    }
+	    deviation = Math.sqrt(deviation / participantCount);
+
+	    activityDTO.setDifficultyIndex(participantCount == 0 ? null : (double) correctUserCount / participantCount);
+	    activityDTO.setDiscriminationIndex((double) (topUsersCorrect - bottomUsersCorrect) / groupCount);
+	    if (correctUserCount == 0 || incorrectUserCount == 0) {
+		activityDTO.setPointBiserial(0d);
+	    } else {
+		activityDTO.setPointBiserial(
+			(correctUserMarkSum / correctUserCount - incorrectUserMarkSum / incorrectUserCount) / deviation
+				* Math.sqrt(correctUserCount * incorrectUserCount / Math.pow(participantCount, 2)));
+	    }
+	}
+
+	return activityDTO;
+    }
+
+    @Override
+    public QbCollection getCollectionByUid(Long collectionUid) {
+	return qbDAO.find(QbCollection.class, collectionUid);
+    }
+
+    @Override
+    public QbCollection getPublicCollection() {
+	return qbDAO.find(QbCollection.class, 1L);
+    }
+
+    @Override
+    public QbCollection getUserPrivateCollection(int userId) {
+	Map<String, Object> map = new HashMap<>();
+	map.put("userId", userId);
+	map.put("personal", true);
+	List<QbCollection> result = qbDAO.findByProperties(QbCollection.class, map);
+	if (!result.isEmpty()) {
+	    return result.get(0);
+	}
+
+	// is an user does not have a private collection yet, create it
+	QbCollection collection = new QbCollection();
+	collection.setName("My questions");
+	collection.setUserId(userId);
+	collection.setPersonal(true);
+	qbDAO.insert(collection);
+	return collection;
+    }
+
+    @Override
+    public List<QbCollection> getUserOwnCollections(int userId) {
+	Map<String, Object> map = new HashMap<>();
+	map.put("userId", userId);
+	map.put("personal", false);
+	List<QbCollection> result = qbDAO.findByProperties(QbCollection.class, map);
+	Collections.sort(result, COLLECTION_NAME_COMPARATOR);
+	return result;
+    }
+
+    @Override
+    public List<QbQuestion> getCollectionQuestions(long collectionUid) {
+	return qbDAO.getCollectionQuestions(collectionUid);
+    }
+
+    @Override
+    public List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
+	    String orderDirection, String search) {
+	return qbDAO.getCollectionQuestions(collectionUid, offset, limit, orderBy, orderDirection, search);
+    }
+
+    @Override
+    public int getCountCollectionQuestions(long collectionUid, String search) {
+	return qbDAO.getCountCollectionQuestions(collectionUid, search);
+    }
+
+    @Override
+    public List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid) {
+	return qbDAO.getQuestionCollectionsByUid(qbQuestionUid);
+    }
+
+    @Override
+    public List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId) {
+	return qbDAO.getQuestionCollectionsByQuestionId(qbQuestionId);
+    }
+
+    @Override
+    public QbCollection addCollection(int userId, String name) {
+	QbCollection collection = new QbCollection();
+	collection.setName(name);
+	collection.setUserId(userId);
+	qbDAO.insert(collection);
+	return collection;
+    }
+
+    @Override
+    public void removeCollection(long collectionUid) {
+	if (getCountCollectionQuestions(collectionUid, null) > 0) {
+	    throw new InvalidParameterException("Can not remove a collection with questions");
+	}
+	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
+	if (collection.getUserId() == null || collection.isPersonal()) {
+	    throw new InvalidParameterException("Attempt to remove a private or the public question bank collection");
+	}
+	qbDAO.delete(collection);
+    }
+
+    @Override
+    public boolean removeQuestionByUid(long qbQuestionUid) {
+	boolean removeQuestionPossible = removeQuestionPossibleByUid(qbQuestionUid);
+	if (!removeQuestionPossible) {
+	    // if the question is used in a Learning Design, do not allow to remove it
+	    return false;
+	}
+	qbDAO.deleteById(QbQuestion.class, qbQuestionUid);
+	return true;
+    }
+
+    @Override
+    public boolean removeQuestionByQuestionId(int qbQuestionId) {
+	boolean removeQuestionPossible = removeQuestionPossibleByQuestionId(qbQuestionId);
+	if (!removeQuestionPossible) {
+	    // if the question is used in a Learning Design, do not allow to remove it
+	    return false;
+	}
+	Map<String, Object> properties = new HashMap<>();
+	properties.put("questionId", qbQuestionId);
+	qbDAO.deleteByProperties(QbQuestion.class, properties);
+	return true;
+    }
+
+    @Override
+    public boolean removeQuestionPossibleByUid(long qbQuestionUid) {
+	Map<String, Object> properties = new HashMap<>();
+	properties.put("qbQuestion.uid", qbQuestionUid);
+	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
+    }
+
+    @Override
+    public boolean removeQuestionPossibleByQuestionId(int qbQuestionId) {
+	Map<String, Object> properties = new HashMap<>();
+	properties.put("qbQuestion.questionId", qbQuestionId);
+	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
+    }
+
+    @Override
+    public Organisation shareCollection(long collectionUid, int organisationId) {
+	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
+	if (collection.getUserId() == null || collection.isPersonal()) {
+	    throw new InvalidParameterException("Attempt to share a private or the public question bank collection");
+	}
+	Organisation organisation = qbDAO.find(Organisation.class, organisationId);
+	collection.getOrganisations().add(organisation);
+	qbDAO.update(collection);
+	return organisation;
+    }
+
+    @Override
+    public void unshareCollection(long collectionUid, int organisationId) {
+	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
+	if (collection.getUserId() == null || collection.isPersonal()) {
+	    throw new InvalidParameterException("Attempt to unshare a private or the public question bank collection");
+	}
+	Iterator<Organisation> orgIterator = collection.getOrganisations().iterator();
+	while (orgIterator.hasNext()) {
+	    if (orgIterator.next().getOrganisationId().equals(organisationId)) {
+		orgIterator.remove();
+		break;
+	    }
+	}
+	qbDAO.update(collection);
+    }
+
+    @Override
+    public void addQuestionToCollection(long collectionUid, int qbQuestionId, boolean copy) {
+	int addQbQuestionId = qbQuestionId;
+	if (copy) {
+	    List<QbQuestion> questions = getQuestionsByQuestionId(qbQuestionId);
+	    QbQuestion question = questions.get(0);
+	    QbQuestion newQuestion = question.clone();
+	    addQbQuestionId = getMaxQuestionId();
+	    newQuestion.setQuestionId(addQbQuestionId);
+	    newQuestion.setVersion(1);
+	    newQuestion.setCreateDate(new Date());
+	    newQuestion.clearID();
+	    qbDAO.insert(newQuestion);
+	}
+	qbDAO.addCollectionQuestion(collectionUid, addQbQuestionId);
+    }
+
+    @Override
+    public void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
+	    Collection<Integer> excludedQbQuestionIds, boolean copy) {
+	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(sourceCollectionUid,
+		excludedQbQuestionIds);
+	for (Integer questionId : includedIds) {
+	    addQuestionToCollection(targetCollectionUid, questionId, copy);
+	}
+    }
+
+    @Override
+    public boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid) {
+	QbQuestion question = getQuestionByUid(qbQuestionUid);
+	return removeQuestionFromCollectionByQuestionId(collectionUid, question.getQuestionId());
+    }
+
+    @Override
+    public boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId) {
+	Collection<QbCollection> collections = getQuestionCollectionsByQuestionId(qbQuestionId);
+	int size = collections.size();
+	if (size <= 1) {
+	    // if the question is in its last collection, try to remove it permanently
+	    return removeQuestionByQuestionId(qbQuestionId);
+	}
+	qbDAO.removeCollectionQuestion(collectionUid, qbQuestionId);
+	return true;
+    }
+
+    @Override
+    public Collection<Integer> removeQuestionFromCollection(long collectionUid,
+	    Collection<Integer> excludedQbQuestionIds) {
+	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(collectionUid, excludedQbQuestionIds);
+	Collection<Integer> retainedQuestionIds = new HashSet<>();
+	for (Integer questionId : includedIds) {
+	    boolean deleted = removeQuestionFromCollectionByQuestionId(collectionUid, questionId);
+	    if (!deleted) {
+		retainedQuestionIds.add(questionId);
+	    }
+	}
+	return retainedQuestionIds;
+    }
+
+    @Override
+    public List<Organisation> getShareableWithOrganisations(long collectionUid, int userId) {
+	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
+	if (collection.getUserId() == null || collection.isPersonal()) {
+	    return null;
+	}
+
+	List<Organisation> result = new ArrayList<>();
+	Map<Integer, Set<Integer>> roles = userManagementService.getRolesForUser(userId);
+	for (Entry<Integer, Set<Integer>> roleEntry : roles.entrySet()) {
+	    Integer organisationId = roleEntry.getKey();
+	    for (Organisation organisation : collection.getOrganisations()) {
+		if (organisation.getOrganisationId().equals(organisationId)) {
+		    organisationId = null;
+		    break;
+		}
+	    }
+	    if (organisationId != null && roleEntry.getValue().contains(Role.ROLE_AUTHOR)) {
+		Organisation organisation = qbDAO.find(Organisation.class, organisationId);
+		result.add(organisation);
+	    }
+	}
+
+	return result;
+    }
+
+    @Override
+    public void releaseFromCache(Object object) {
+	qbDAO.releaseFromCache(object);
+    }
+
+    @Override
+    public List<QbCollection> getUserCollections(int userId) {
+	List<QbCollection> collections = new LinkedList<>();
+
+	QbCollection privateCollection = getUserPrivateCollection(userId);
+	collections.add(privateCollection);
+
+	collections.addAll(getUserOwnCollections(userId));
+
+	QbCollection publicCollection = getPublicCollection();
+	collections.add(publicCollection);
+
+	return collections;
+    }
+
+    @Override
+    public QbCollection getCollection(long collectionUid) {
+	return qbDAO.find(QbCollection.class, collectionUid);
+    }
+
+    @Override
+    public int getCountQuestionActivitiesByUid(long qbQuestionUid) {
+	return qbDAO.getCountQuestionActivitiesByUid(qbQuestionUid);
+    }
+
+    @Override
+    public int getCountQuestionActivitiesByQuestionId(int qbQuestionId) {
+	return qbDAO.getCountQuestionActivitiesByQuestionId(qbQuestionId);
+    }
+
+    @Override
+    public void changeCollectionName(long collectionUid, String name) {
+	QbCollection collection = getCollection(collectionUid);
+	collection.setName(name);
+	qbDAO.update(collection);
+    }
+
+    @Override
+    public boolean isQuestionInUserCollection(int qbQuestionId, int userId) {
+	return qbDAO.isQuestionInUserCollection(userId, qbQuestionId);
+    }
+
+    public void setQbDAO(IQbDAO qbDAO) {
+	this.qbDAO = qbDAO;
+    }
+
+    public void setGradebookService(IGradebookService gradebookService) {
+	this.gradebookService = gradebookService;
+    }
+
+    public void setLamsCoreToolService(ILamsCoreToolService lamsCoreToolService) {
+	this.lamsCoreToolService = lamsCoreToolService;
+    }
+
+    public void setUserManagementService(IUserManagementService userManagementService) {
+	this.userManagementService = userManagementService;
+    }
 }
\ No newline at end of file