Index: idea_project/.idea/.name
===================================================================
diff -u -r399094fd7734e7d5bed9bd9a40ca4a463ff02b35 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- idea_project/.idea/.name	(.../.name)	(revision 399094fd7734e7d5bed9bd9a40ca4a463ff02b35)
+++ idea_project/.idea/.name	(.../.name)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -1 +1 @@
-LAMS
\ No newline at end of file
+LAMS 4.6
\ No newline at end of file
Index: idea_project/.idea/runConfigurations/WildFly.xml
===================================================================
diff -u -r10ada76a9a401c0fb4842e107613be3ffcc8430b -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- idea_project/.idea/runConfigurations/WildFly.xml	(.../WildFly.xml)	(revision 10ada76a9a401c0fb4842e107613be3ffcc8430b)
+++ idea_project/.idea/runConfigurations/WildFly.xml	(.../WildFly.xml)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -1,5 +1,5 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="WildFly" type="JBossConfiguration" factoryName="Local" APPLICATION_SERVER_NAME="JBoss/WildFly 14.0.1.Final" ALTERNATIVE_JRE_ENABLED="true" ALTERNATIVE_JRE_PATH="11">
+  <configuration default="false" name="WildFly" type="JBossConfiguration" factoryName="Local" APPLICATION_SERVER_NAME="WildFly 4.6 server" ALTERNATIVE_JRE_ENABLED="true" ALTERNATIVE_JRE_PATH="11">
     <option name="OPEN_IN_BROWSER" value="false" />
     <option name="UPDATING_POLICY" value="restart-server" />
     <deployment />
Index: lams_tool_doku/conf/language/lams/ApplicationResources.properties
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -99,12 +99,14 @@
 label.authoring.advance.gallery.walk.info2 = When enabled, after you start Gallery Walk in the lesson, the document created for each team is shared to all other teams. Teams then, can give each others feedback and rate each others' work.
 label.authoring.advance.gallery.walk.instructions =  Instructions for Gallery Walk (ie: Please review other groups' work and make sure you add your review/comments)
 label.authoring.advance.gallery.walk.read.only.tooltip = Students will not be able to comment or rate other teams' work.
-label.authoring.advance.gallery.walk.batch = Limit number of other teams being reviewed by each team
-label.authoring.advance.gallery.walk.batch.tooltip = Each team will review no less than the number of teams specified here. In some situations (ie: small number of teams), this number may be exceeded.
+label.authoring.advance.gallery.walk.cluster = Limit number of other teams being reviewed by each team
+label.authoring.advance.gallery.walk.cluster.tooltip = Each team will review no less than the number of teams specified here. In some situations (ie: small number of teams), this number may be exceeded.
+label.authoring.advance.gallery.walk.cluster.0 = (0 means each team will review all other teams)
 monitoring.summary.gallery.walk.start = Start Gallery Walk
 monitoring.summary.gallery.walk.start.confirm = Are you sure you want to finish collaboration phase and start Gallery Walk? You will not be able to return to collaboration phase.
 monitoring.summary.gallery.walk.finish = Finish Gallery Walk
 monitoring.summary.gallery.walk.finish.confirm = Are you sure you want to finish Gallery Walk? You will not be able to restart Gallery Walk.
+monitoring.summary.gallery.walk.cluster.members = Rated by
 label.gallery.walk = Gallery Walk
 label.gallery.walk.wait.finish = The Gallery Walk activity has not been set as completed by the teacher. If you have completed, please contact the teacher for assistance.
 label.rating = Rating
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dbupdates/patch20230504.sql
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dbupdates/patch20230504.sql	(.../patch20230504.sql)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dbupdates/patch20230504.sql	(.../patch20230504.sql)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -3,9 +3,20 @@
 SET FOREIGN_KEY_CHECKS=0;
 -- Put all sql statements below here
 
--- LDEV-5391 Add batches to gallery walk
-ALTER TABLE tl_ladoku11_dokumaran ADD COLUMN gallery_walk_batch_size TINYINT UNSIGNED NOT NULL DEFAULT '0' AFTER gallery_walk_read_only;
+-- LDEV-5391 Add clusters to gallery walk
+ALTER TABLE tl_ladoku11_dokumaran ADD COLUMN gallery_walk_cluster_size TINYINT UNSIGNED NOT NULL DEFAULT '0' AFTER gallery_walk_read_only;
 
+CREATE TABLE tl_ladoku11_gallery_walk_cluster (
+    source_session_uid BIGINT NOT NULL,
+    target_session_uid BIGINT NOT NULL,
+    PRIMARY KEY (source_session_uid, target_session_uid),
+    CONSTRAINT FK_tl_ladoku11_gallery_walk_cluster_1 FOREIGN KEY (source_session_uid)
+        REFERENCES tl_ladoku11_session(uid) ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT FK_tl_ladoku11_gallery_walk_cluster_2 FOREIGN KEY (target_session_uid)
+        REFERENCES tl_ladoku11_session(uid) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+
 -- Put all sql statements above here
 
 -- If there were no errors, commit and restore autocommit to on
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dto/SessionDTO.java
===================================================================
diff -u -r8d372a4476d25a498b5af8c04e82576edc7b0976 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dto/SessionDTO.java	(.../SessionDTO.java)	(revision 8d372a4476d25a498b5af8c04e82576edc7b0976)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/dto/SessionDTO.java	(.../SessionDTO.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -24,6 +24,9 @@
 
 import org.lamsfoundation.lams.rating.dto.ItemRatingDTO;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
+
 public class SessionDTO {
 
     private Long sessionId;
@@ -34,6 +37,7 @@
     private ItemRatingDTO itemRatingDto;
     private int numberOfLearners;
     private boolean sessionFinished;
+    private final Map<Long, String> galleryWalkClusterMembers = new LinkedHashMap<>();
 
     public Long getSessionId() {
 	return sessionId;
@@ -84,18 +88,22 @@
     }
 
     public int getNumberOfLearners() {
-        return numberOfLearners;
+	return numberOfLearners;
     }
 
     public void setNumberOfLearners(int numberOfLearners) {
-        this.numberOfLearners = numberOfLearners;
+	this.numberOfLearners = numberOfLearners;
     }
 
     public boolean isSessionFinished() {
-        return sessionFinished;
+	return sessionFinished;
     }
 
     public void setSessionFinished(boolean sesssionFinished) {
-        this.sessionFinished = sesssionFinished;
+	this.sessionFinished = sesssionFinished;
     }
+
+    public Map<Long, String> getGalleryWalkClusterMembers() {
+	return galleryWalkClusterMembers;
+    }
 }
\ No newline at end of file
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/Dokumaran.java
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/Dokumaran.java	(.../Dokumaran.java)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/Dokumaran.java	(.../Dokumaran.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -118,8 +118,8 @@
     @Column(name = "gallery_walk_read_only")
     private boolean galleryWalkReadOnly;
 
-    @Column(name = "gallery_walk_batch_size")
-    private int galleryWalkBatchSize;
+    @Column(name = "gallery_walk_cluster_size")
+    private int galleryWalkClusterSize;
 
     @Column(name = "gallery_walk_started")
     private boolean galleryWalkStarted;
@@ -481,12 +481,12 @@
 	this.galleryWalkReadOnly = galleryWalkReadOnly;
     }
 
-    public int getGalleryWalkBatchSize() {
-	return galleryWalkBatchSize;
+    public int getGalleryWalkClusterSize() {
+	return galleryWalkClusterSize;
     }
 
-    public void setGalleryWalkBatchSize(int galleryWalkBatchSize) {
-	this.galleryWalkBatchSize = galleryWalkBatchSize;
+    public void setGalleryWalkClusterSize(int galleryWalkClusterSize) {
+	this.galleryWalkClusterSize = galleryWalkClusterSize;
     }
 
     public boolean isGalleryWalkStarted() {
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/DokumaranSession.java
===================================================================
diff -u -r5ce80833bb0828de219fc5b59e9e73c365da8559 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/DokumaranSession.java	(.../DokumaranSession.java)	(revision 5ce80833bb0828de219fc5b59e9e73c365da8559)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/model/DokumaranSession.java	(.../DokumaranSession.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -23,20 +23,16 @@
 
 package org.lamsfoundation.lams.tool.dokumaran.model;
 
-import java.util.Date;
-
-import javax.persistence.Column;
-import javax.persistence.Entity;
-import javax.persistence.FetchType;
-import javax.persistence.GeneratedValue;
-import javax.persistence.GenerationType;
-import javax.persistence.Id;
-import javax.persistence.JoinColumn;
-import javax.persistence.ManyToOne;
-import javax.persistence.Table;
-
+import org.hibernate.annotations.SortComparator;
 import org.lamsfoundation.lams.etherpad.util.EtherpadUtil;
+import org.lamsfoundation.lams.tool.dokumaran.util.DokumaranSessionComparator;
 
+import javax.persistence.*;
+import java.util.Date;
+import java.util.Objects;
+import java.util.Set;
+import java.util.TreeSet;
+
 /**
  * Dokumaran session
  *
@@ -46,6 +42,8 @@
 @Table(name = "tl_ladoku11_session")
 public class DokumaranSession {
 
+    public static final DokumaranSessionComparator SESSION_NAME_COMPARATOR = new DokumaranSessionComparator();
+
     @Id
     @Column
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -81,9 +79,17 @@
     @Column(name = "etherpad_read_only_id")
     private String etherpadReadOnlyId;
 
+    @ManyToMany(fetch = FetchType.LAZY)
+    @JoinTable(name = "tl_ladoku11_gallery_walk_cluster", joinColumns = {
+	    @JoinColumn(name = "source_session_uid") }, inverseJoinColumns = {
+	    @JoinColumn(name = "target_session_uid") })
+    @SortComparator(DokumaranSessionComparator.class)
+    private Set<DokumaranSession> galleryWalkCluster = new TreeSet<>(SESSION_NAME_COMPARATOR);
+
     // **********************************************************
     // Get/Set methods
     // **********************************************************
+
     /**
      * @return Returns the learnerID.
      */
@@ -144,7 +150,7 @@
 
     /**
      * @param sessionName
-     *            The session name to set.
+     * 	The session name to set.
      */
     public void setSessionName(String sessionName) {
 	this.sessionName = sessionName;
@@ -167,7 +173,7 @@
 
     /**
      * @param etherpadReadOnlyId
-     *            The etherpadReadOnlyId to set.
+     * 	The etherpadReadOnlyId to set.
      */
     public void setEtherpadGroupId(String etherpadGroupId) {
 	this.etherpadGroupId = etherpadGroupId;
@@ -182,7 +188,7 @@
 
     /**
      * @param etherpadReadOnlyId
-     *            The etherpadReadOnlyId to set.
+     * 	The etherpadReadOnlyId to set.
      */
     public void setEtherpadReadOnlyId(String etherpadReadOnlyId) {
 	this.etherpadReadOnlyId = etherpadReadOnlyId;
@@ -191,4 +197,27 @@
     public String getPadId() {
 	return EtherpadUtil.getPadId(etherpadGroupId);
     }
+
+    public Set<DokumaranSession> getGalleryWalkCluster() {
+	return galleryWalkCluster;
+    }
+
+    public void setGalleryWalkCluster(Set<DokumaranSession> galleryWalkCluster) {
+	this.galleryWalkCluster = galleryWalkCluster;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+	if (this == o)
+	    return true;
+	if (o == null || getClass() != o.getClass())
+	    return false;
+	DokumaranSession that = (DokumaranSession) o;
+	return Objects.equals(uid, that.uid);
+    }
+
+    @Override
+    public int hashCode() {
+	return Objects.hash(uid);
+    }
 }
\ No newline at end of file
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/DokumaranService.java
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/DokumaranService.java	(.../DokumaranService.java)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/DokumaranService.java	(.../DokumaranService.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -34,7 +34,6 @@
 import org.lamsfoundation.lams.etherpad.service.IEtherpadService;
 import org.lamsfoundation.lams.etherpad.util.EtherpadUtil;
 import org.lamsfoundation.lams.learning.service.ILearnerService;
-import org.lamsfoundation.lams.learningdesign.Group;
 import org.lamsfoundation.lams.learningdesign.Grouping;
 import org.lamsfoundation.lams.learningdesign.ToolActivity;
 import org.lamsfoundation.lams.learningdesign.service.ExportToolContentException;
@@ -427,11 +426,12 @@
     }
 
     @Override
-    public List<SessionDTO> getSummary(Long contentId, Long ratingUserId) {
+    public List<SessionDTO> getSummary(Long contentId, Long ratingUserUid) {
 	// get all sessions in a dokumaran and retrieve all dokumaran items under this session
 	// plus initial dokumaran items by author creating (resItemList)
 	List<DokumaranSession> sessionList = dokumaranSessionDao.getByContentId(contentId);
 	Dokumaran dokumaran = dokumaranDao.getByContentId(contentId);
+	DokumaranUser user = ratingUserUid == null ? null : dokumaranDao.find(DokumaranUser.class, ratingUserUid);
 
 	Map<Long, ItemRatingDTO> itemRatingDtoMap = null;
 	if (dokumaran.isGalleryWalkStarted()) {
@@ -451,13 +451,23 @@
 		    .collect(Collectors.mapping(DokumaranSession::getSessionId, Collectors.toSet()));
 
 	    List<ItemRatingDTO> itemRatingDtos = ratingService.getRatingCriteriaDtos(contentId, null, itemIds, true,
-		    ratingUserId);
+		    user == null ? null : user.getUserId());
 	    // Mapping of Item ID -> DTO
 	    itemRatingDtoMap = itemRatingDtos.stream()
 		    .collect(Collectors.toMap(ItemRatingDTO::getItemId, Function.identity()));
 	}
 
 	List<SessionDTO> groupList = new ArrayList<>();
+	if (user != null && dokumaran.getGalleryWalkClusterSize() > 0) {
+	    DokumaranSession session = user.getSession();
+	    if (!session.getGalleryWalkCluster().isEmpty()) {
+		sessionList = new ArrayList<>(session.getGalleryWalkCluster());
+		sessionList.add(session);
+	    }
+	}
+
+	Collections.sort(sessionList, DokumaranSession.SESSION_NAME_COMPARATOR);
+
 	for (DokumaranSession session : sessionList) {
 	    // one new group for one session.
 	    SessionDTO group = new SessionDTO();
@@ -478,6 +488,15 @@
 		group.setItemRatingDto(itemRatingDtoMap.get(session.getSessionId()));
 	    }
 
+	    if (!session.getGalleryWalkCluster().isEmpty()) {
+		List<DokumaranSession> cluster = new ArrayList<>(session.getGalleryWalkCluster());
+		Collections.sort(cluster, DokumaranSession.SESSION_NAME_COMPARATOR);
+		for (DokumaranSession clusterMember : cluster) {
+		    group.getGalleryWalkClusterMembers()
+			    .put(clusterMember.getSessionId(), clusterMember.getSessionName());
+		}
+	    }
+
 	    groupList.add(group);
 	}
 
@@ -602,6 +621,8 @@
 	dokumaran.setGalleryWalkStarted(true);
 	dokumaranDao.saveObject(dokumaran);
 
+	assignSessionsForGalleryWalk(toolContentId);
+
 	sendGalleryWalkRefreshRequest(dokumaran);
     }
 
@@ -644,7 +665,96 @@
 	learnerService.createCommandForLearners(dokumaran.getContentId(), userIds, jsonCommand.toString());
     }
 
+    /**
+     * If gallery walk is clustered, it assigns sessions to clusters.
+     */
     @Override
+    public void assignSessionsForGalleryWalk(long toolContentId) {
+	Dokumaran dokumaran = getDokumaranByContentId(toolContentId);
+	int clusterSize = dokumaran.getGalleryWalkClusterSize();
+	if (clusterSize == 0) {
+	    return;
+	}
+	boolean isGrouped = isGroupedActivity(toolContentId);
+	if (!isGrouped) {
+	    return;
+	}
+
+	// focus only on sessions that are not assigned to any cluster yet
+	List<DokumaranSession> allSessions = dokumaranSessionDao.getByContentId(toolContentId);
+	List<DokumaranSession> nonAssignedSessions = allSessions.stream()
+		.filter(session -> session.getGalleryWalkCluster().isEmpty()).collect(Collectors.toList());
+	if (nonAssignedSessions.isEmpty()) {
+	    return;
+	}
+
+	Random random = new Random();
+	List<DokumaranSession> nonFullClusterSessions = allSessions.stream()
+		.filter(session -> session.getGalleryWalkCluster().size() < clusterSize).collect(Collectors.toList());
+	// to each session from nonAssignedSessions assign random sessions from nonFullClusterSessions up to at least clusterSize
+	for (DokumaranSession nonAssignedSession : nonAssignedSessions) {
+	    nonFullClusterSessions.remove(nonAssignedSession);
+	    List<DokumaranSession> nonFullClusterSessionsCopy = nonFullClusterSessions.stream()
+		    .filter(session -> !session.getGalleryWalkCluster().contains(nonAssignedSession))
+		    .collect(Collectors.toList());
+
+	    // first try to find sessions which are not full yet
+	    while (nonAssignedSession.getGalleryWalkCluster().size() < clusterSize
+		    && !nonFullClusterSessionsCopy.isEmpty()) {
+		DokumaranSession targetSession = nonFullClusterSessionsCopy.get(
+			random.nextInt(nonFullClusterSessionsCopy.size()));
+
+		// create a new collection with all cluster members and assign it to each member
+		Set<DokumaranSession> cluster = new HashSet<>();
+		cluster.add(nonAssignedSession);
+		cluster.addAll(nonAssignedSession.getGalleryWalkCluster());
+		cluster.add(targetSession);
+		cluster.addAll(targetSession.getGalleryWalkCluster());
+
+		for (DokumaranSession clusterMember : cluster) {
+		    // do not participate in further cluster assignments for this nonAssignedSession
+		    nonFullClusterSessionsCopy.remove(clusterMember);
+		    clusterMember.getGalleryWalkCluster().addAll(cluster);
+		    // do not assign itself as a cluster member
+		    clusterMember.getGalleryWalkCluster().remove(clusterMember);
+		    if (clusterMember.getGalleryWalkCluster().size() >= clusterSize) {
+			// make is unavailable for further cluster assignments for any next nonAssignedSession
+			nonFullClusterSessions.remove(clusterMember);
+		    }
+		}
+	    }
+
+	    // if cluster is not full but we run out of sessions which are not full yet, assign to random cluster
+	    // this will make some clusters bigger than clusterSize
+	    if (nonAssignedSession.getGalleryWalkCluster().size() < clusterSize) {
+		// assign to random cluster
+		List<DokumaranSession> otherSessions = allSessions.stream()
+			.filter(session -> !session.equals(nonAssignedSession) && !session.getGalleryWalkCluster()
+				.contains(nonAssignedSession)).collect(Collectors.toList());
+		while (nonAssignedSession.getGalleryWalkCluster().size() < clusterSize && !otherSessions.isEmpty()) {
+		    DokumaranSession targetSession = otherSessions.get(random.nextInt(otherSessions.size()));
+
+		    Set<DokumaranSession> cluster = new HashSet<>();
+		    cluster.add(nonAssignedSession);
+		    cluster.addAll(nonAssignedSession.getGalleryWalkCluster());
+		    cluster.add(targetSession);
+		    cluster.addAll(targetSession.getGalleryWalkCluster());
+
+		    for (DokumaranSession clusterMember : cluster) {
+			otherSessions.remove(clusterMember);
+			clusterMember.getGalleryWalkCluster().addAll(cluster);
+			clusterMember.getGalleryWalkCluster().remove(clusterMember);
+		    }
+		}
+	    }
+	}
+
+	for (DokumaranSession session : allSessions) {
+	    dokumaranSessionDao.update(session);
+	}
+    }
+
+    @Override
     public boolean isGroupedActivity(long toolContentID) {
 	return toolService.isGroupedActivity(toolContentID);
     }
@@ -684,38 +794,6 @@
 	return contentId;
     }
 
-    private List<List<DokumaranSession>> getSessionsForGalleryWalk(long toolContentId) {
-	List<List<DokumaranSession>> result = new ArrayList<>();
-
-	Dokumaran dokumaran = getDokumaranByContentId(toolContentId);
-	List<DokumaranSession> allSessions = dokumaranSessionDao.getByContentId(toolContentId);
-	int batchSize = dokumaran.getGalleryWalkBatchSize();
-	Grouping grouping = getGrouping(toolContentId);
-	if (batchSize == 0 || grouping == null) {
-	    result.add(allSessions);
-	    return result;
-	}
-	// for authors batch size is how many *other* groups given group will rate,
-	// but here we need to calculate how many groups will be in batch
-	batchSize++;
-
-	List<String> groupNames = grouping.getGroups().stream().map(Group::getGroupName).sorted().collect(Collectors.toList());
-	List<List<String>> groupNameBatches = new ArrayList<>();
-	Random random = new Random(toolContentId);
-	// create random batches of group names, each minimum size of batchSize
-	while (!groupNames.isEmpty()) {
-	    int batchSizeForThisBatch = Math.min(batchSize, groupNames.size());
-	    List<String> groupNameBatch = new ArrayList<>();
-	    for (int i = 0; i < batchSizeForThisBatch; i++) {
-		int randomIndex = random.nextInt(groupNames.size());
-		groupNameBatch.add(groupNames.remove(randomIndex));
-	    }
-	    groupNameBatches.add(groupNameBatch);
-	}
-
-
-	return result;
-    }
     // *******************************************************************************
     // ToolContentManager, ToolSessionManager methods
     // *******************************************************************************
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/IDokumaranService.java
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/IDokumaranService.java	(.../IDokumaranService.java)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/service/IDokumaranService.java	(.../IDokumaranService.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -185,7 +185,7 @@
     /**
      * Return monitoring summary list. The return value is list of dokumaran summaries for each groups.
      */
-    List<SessionDTO> getSummary(Long contentId, Long ratingUserId);
+    List<SessionDTO> getSummary(Long contentId, Long ratingUserUid);
 
     /**
      * Create refection entry into notebook tool.
@@ -237,7 +237,7 @@
 
     void enableGalleryWalkLearnerEdit(long toolContentId) throws IOException;
 
-    // List<List<DokumaranSession>> getGalleryWalkSessionBatches(long toolContentId);
+    void assignSessionsForGalleryWalk(long toolContentId);
 
     void changeLeaderForGroup(long toolSessionId, long leaderUserId);
 
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/util/DokumaranSessionComparator.java
===================================================================
diff -u
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/util/DokumaranSessionComparator.java	(revision 0)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/util/DokumaranSessionComparator.java	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -0,0 +1,25 @@
+package org.lamsfoundation.lams.tool.dokumaran.util;
+
+import org.lamsfoundation.lams.tool.dokumaran.model.DokumaranSession;
+
+import java.util.Comparator;
+
+public class DokumaranSessionComparator implements Comparator<DokumaranSession> {
+    @Override
+    public int compare(DokumaranSession o1, DokumaranSession o2) {
+	if (o1 != null && o2 != null) {
+	    String name1 = o1.getSessionName().replaceAll("\\D+", "");
+	    String name2 = o2.getSessionName().replaceAll("\\D+", "");
+	    if (name1.length() == 0 || name2.length() == 0) {
+		return name1.compareTo(name2);
+	    }
+	    Long num1 = Long.parseLong(name1);
+	    Long num2 = Long.parseLong(name2);
+	    return num1.compareTo(num2);
+	} else if (o1 != null) {
+	    return 1;
+	} else {
+	    return -1;
+	}
+    }
+}
\ No newline at end of file
Index: lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/web/controller/LearningController.java
===================================================================
diff -u -rc707049495e78958e693f8161cb8e71e7f5d6b69 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/web/controller/LearningController.java	(.../LearningController.java)	(revision c707049495e78958e693f8161cb8e71e7f5d6b69)
+++ lams_tool_doku/src/java/org/lamsfoundation/lams/tool/dokumaran/web/controller/LearningController.java	(.../LearningController.java)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -23,19 +23,8 @@
 
 package org.lamsfoundation.lams.tool.dokumaran.web.controller;
 
-import java.io.IOException;
-import java.net.URISyntaxException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Date;
-import java.util.List;
-import java.util.Set;
-import java.util.TimeZone;
-
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import javax.servlet.http.HttpSession;
-
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import org.apache.commons.lang.StringUtils;
 import org.apache.log4j.Logger;
 import org.lamsfoundation.lams.etherpad.EtherpadException;
@@ -68,8 +57,12 @@
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
 
-import com.fasterxml.jackson.databind.node.JsonNodeFactory;
-import com.fasterxml.jackson.databind.node.ObjectNode;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.*;
 
 /**
  * @author Steve.Ni
@@ -93,10 +86,8 @@
      * This method will avoid read database again and lost un-saved resouce item lost when user "refresh page",
      *
      * @throws EtherpadException
-     *
      * @throws DokumaranConfigurationException
      * @throws URISyntaxException
-     *
      */
     @RequestMapping("/start")
     private String start(HttpServletRequest request, HttpServletResponse response)
@@ -156,8 +147,8 @@
 	}
 
 	boolean isUserLeader = (user != null) && dokumaranService.isUserLeader(leaders, user.getUserId());
-	boolean hasEditRight = !dokumaran.isUseSelectLeaderToolOuput()
-		|| dokumaran.isUseSelectLeaderToolOuput() && isUserLeader;
+	boolean hasEditRight =
+		!dokumaran.isUseSelectLeaderToolOuput() || dokumaran.isUseSelectLeaderToolOuput() && isUserLeader;
 	sessionMap.put(DokumaranConstants.ATTR_HAS_EDIT_RIGHT, hasEditRight);
 	sessionMap.put(AttributeNames.PARAM_TOOL_SESSION_ID, toolSessionId);
 	sessionMap.put(DokumaranConstants.ATTR_REFLECTION_ON, dokumaran.isReflectOnActivity());
@@ -203,13 +194,17 @@
 	}
 
 	if (dokumaran.isGalleryWalkStarted()) {
+	    if (dokumaran.getGalleryWalkClusterSize() > 0 && session.getGalleryWalkCluster().isEmpty()) {
+		dokumaranService.assignSessionsForGalleryWalk(dokumaran.getContentId());
+	    }
+
 	    List<SessionDTO> groupList = null;
 	    try {
-		groupList = dokumaranService.getSummary(dokumaran.getContentId(), user.getUserId());
+		groupList = dokumaranService.getSummary(dokumaran.getContentId(), user.getUid());
 	    } catch (HibernateOptimisticLockingFailureException e) {
 		log.warn("Ignoring error caused probably by creating Gallery Walk criteria", e);
 		// simply run the transaction again
-		groupList = dokumaranService.getSummary(dokumaran.getContentId(), user.getUserId());
+		groupList = dokumaranService.getSummary(dokumaran.getContentId(), user.getUid());
 	    }
 	    request.setAttribute(DokumaranConstants.ATTR_SUMMARY_LIST, groupList);
 
@@ -424,4 +419,4 @@
 	}
 	return dokumaranUser;
     }
-}
+}
\ No newline at end of file
Index: lams_tool_doku/web/pages/authoring/advance.jsp
===================================================================
diff -u -rf7eadd2d25a238ea0a2b20b502f93f0f4a4855d9 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/web/pages/authoring/advance.jsp	(.../advance.jsp)	(revision f7eadd2d25a238ea0a2b20b502f93f0f4a4855d9)
+++ lams_tool_doku/web/pages/authoring/advance.jsp	(.../advance.jsp)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -13,7 +13,7 @@
 				$('#gallery-walk-options').slideDown();
 			} else {
 				$('#gallery-walk-options').slideUp()
-				.find('#gallery-walk-read-only').prop('checked', false);
+						.find('#gallery-walk-read-only').prop('checked', false);
 			}
 		}).change();
 
@@ -108,13 +108,15 @@
 			   data-toggle="tooltip" title="<fmt:message key='label.authoring.advance.gallery.walk.read.only.tooltip' />"></i>
 		</div>
 
-		<div class="form-group">
-			<label for="galleryWalkBatchSize">
-				<fmt:message key="label.authoring.advance.gallery.walk.batch" />&nbsp;
+		<div class="form-inline form-group">
+			<label for="galleryWalkClusterSize">
+				<fmt:message key="label.authoring.advance.gallery.walk.cluster" />&nbsp;
 				<i class="fa fa-question-circle" aria-hidden="true" data-toggle="tooltip" data-placement="top" title=""
-				   data-original-title="<fmt:message key="label.authoring.advance.gallery.walk.batch.instructions"/>"></i>
+				   data-original-title="<fmt:message key="label.authoring.advance.gallery.walk.cluster.tooltip"/>"></i>
 			</label>
-			<form:input path="dokumaran.galleryWalkBatchSize" type="number" min="0" max="9" size="2" id="galleryWalkBatchSize" cssClass="form-control input-sm"/>
+			<form:input path="dokumaran.galleryWalkClusterSize" type="number" min="0" max="9" size="2" id="galleryWalkClusterSize"
+						cssClass="form-control input-sm"/>
+			<br><small class="text-muted"><fmt:message key="label.authoring.advance.gallery.walk.cluster.0" /></small>
 		</div>
 
 		<div class="form-group">
Index: lams_tool_doku/web/pages/monitoring/summary.jsp
===================================================================
diff -u -rfc79f9fc1b671f5e2d182b387be8c3987ba73fb3 -rdbb83a20e36def6c8cb9763e542714cef162e0a2
--- lams_tool_doku/web/pages/monitoring/summary.jsp	(.../summary.jsp)	(revision fc79f9fc1b671f5e2d182b387be8c3987ba73fb3)
+++ lams_tool_doku/web/pages/monitoring/summary.jsp	(.../summary.jsp)	(revision dbb83a20e36def6c8cb9763e542714cef162e0a2)
@@ -258,8 +258,8 @@
 					type: 'post',
 					success : function (){
 						$this.closest('.marks-container').find('.copy-mark-button')
-						.data('mark', mark).show()
-						.find('.copy-mark-value').text(mark);
+								.data('mark', mark).show()
+								.find('.copy-mark-value').text(mark);
 					},
 					error: function (request, status, error) {
 						alert('<fmt:message key="messsage.monitoring.learner.marks.update.fail" />');
@@ -317,11 +317,11 @@
 					}
 				}
 			})
-			.bind('pagerInitialized pagerComplete', function(event, options){
-				if ( options.totalRows == 0 ) {
-					$.tablesorter.showError($(this), '<fmt:message key="messsage.monitoring.learner.marks.no.data"/>');
-				}
-			});
+					.bind('pagerInitialized pagerComplete', function(event, options){
+						if ( options.totalRows == 0 ) {
+							$.tablesorter.showError($(this), '<fmt:message key="messsage.monitoring.learner.marks.no.data"/>');
+						}
+					});
 		});
 
 
@@ -419,9 +419,9 @@
 
 	function showChangeLeaderModal(toolSessionId) {
 		$('#doku-monitoring-summary-${sessionMap.toolContentID} #change-leader-modals').empty()
-		.load('<c:url value="/monitoring/displayChangeLeaderForGroupDialogFromActivity.do" />',{
-			toolSessionID : toolSessionId
-		});
+				.load('<c:url value="/monitoring/displayChangeLeaderForGroupDialogFromActivity.do" />',{
+					toolSessionID : toolSessionId
+				});
 	}
 
 	function onChangeLeaderCallback(response, leaderUserId, toolSessionId){
@@ -613,6 +613,17 @@
 
 				</c:when>
 				<c:otherwise>
+					<c:if test="${not empty groupSummary.galleryWalkClusterMembers}">
+						<c:set var="clusterMemberLinks" value="" />
+						<c:forEach var="clusterMember" items="${groupSummary.galleryWalkClusterMembers}" varStatus="status">
+							<c:set var="clusterMemberLinks">${clusterMemberLinks}${status.first ? "" : ",&nbsp;"}
+								<a href="#heading${clusterMember.key}"><c:out value="${clusterMember.value}" /></a></c:set>
+						</c:forEach>
+						<span class="loffset5">
+							<fmt:message key="monitoring.summary.gallery.walk.cluster.members" />&nbsp;${clusterMemberLinks}
+						</span>
+					</c:if>
+
 					<c:if test="${dokumaran.galleryWalkStarted and not dokumaran.galleryWalkReadOnly}">
 						<lams:Rating itemRatingDto="${groupSummary.itemRatingDto}" isItemAuthoredByUser="true" />
 					</c:if>