Index: lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/INoticeboardService.java
===================================================================
diff -u -r0048b5d3c999c59bd1fb45b2b231fa97343801e7 -rdfb239e990a8c19e3c889759bcb733361cf64d6f
--- lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/INoticeboardService.java	(.../INoticeboardService.java)	(revision 0048b5d3c999c59bd1fb45b2b231fa97343801e7)
+++ lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/INoticeboardService.java	(.../INoticeboardService.java)	(revision dfb239e990a8c19e3c889759bcb733361cf64d6f)
@@ -24,6 +24,7 @@
 import org.lamsfoundation.lams.tool.noticeboard.NoticeboardContent;
 import org.lamsfoundation.lams.tool.noticeboard.NoticeboardSession;
 import org.lamsfoundation.lams.tool.noticeboard.NoticeboardUser;
+import java.util.List;
 
 
 /**
@@ -222,4 +223,29 @@
      * @param user The instance of NoticeboardUser to persist
      */
     public void addUser(Long nbSessionId, NoticeboardUser nbUser);
+    
+    /**
+     * <p>Retrieves a list of the session IDs from the given instance of NoticeboardContent</p> 
+     * @param content 
+     * @return list of session ids (Long)
+     */
+    public List getSessionIdsFromContent(NoticeboardContent content);
+    
+    /**
+     * <p>Returns the number of users in this session</p>
+     * @param session
+     * @return The number of users in the session
+     */
+    public int getNumberOfUsersInSession(NoticeboardSession session);
+    
+    /**
+     * <p>Finds the number of learners that have participated in this tool activity
+     * with the given toolContentId. It finds all the toolSessionIds relating to this
+     * toolContentId, and calculates the number of users in each tool session(group).
+     * Returns the total number of users across all sessions </p>
+     * @param toolContentId 
+     * @return the total number of users for this tool activity
+     */
+    public int calculateTotalNumberOfUsers(Long toolContentId);
+    
 }
Index: lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/NoticeboardServicePOJO.java
===================================================================
diff -u -r49efb9ff777234a7d8c543254ba8631ea2a0bd53 -rdfb239e990a8c19e3c889759bcb733361cf64d6f
--- lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/NoticeboardServicePOJO.java	(.../NoticeboardServicePOJO.java)	(revision 49efb9ff777234a7d8c543254ba8631ea2a0bd53)
+++ lams_tool_nb/src/java/org/lamsfoundation/lams/tool/noticeboard/service/NoticeboardServicePOJO.java	(.../NoticeboardServicePOJO.java)	(revision dfb239e990a8c19e3c889759bcb733361cf64d6f)
@@ -349,6 +349,21 @@
 		
 	}
 	
+	/** @see org.lamsfoundation.lams.tool.noticeboard.service.INoticeboardService#getSessionIdsFromContent(org.lamsfoundation.lams.tool.noticeboard.NoticeboardContent) */
+	public List getSessionIdsFromContent(NoticeboardContent content)
+	{
+	    List list = null;
+	    try
+	    {
+	        list = nbSessionDAO.getSessionsFromContent(content);
+	    }
+	    catch(DataAccessException e)
+	    {
+	        throw new NbApplicationException("EXCEPTION: An exception has occurred while trying to the list of session ids from content "
+					+ e.getMessage(), e);
+	    }
+	    return list;
+	}
 	
 	/* ==============================================================================
 	 * Methods for access to NoticeboardUser objects
@@ -483,6 +498,48 @@
 	    }
 	}
 	
+	/** @see org.lamsfoundation.lams.tool.noticeboard.service.INoticeboardService#getNumberOfUsersInSession(org.lamsfoundation.lams.tool.noticeboard.oticeboardSession) */
+	public int getNumberOfUsersInSession(NoticeboardSession session)
+	{
+	    int numberOfUsers;
+	    try
+	    {
+	        numberOfUsers = nbUserDAO.getNumberOfUsers(session);
+	    }
+	    catch (DataAccessException e)
+	    {
+	        throw new NbApplicationException("EXCEPTION: An exception has occurred while trying to get the number of users in the session: "
+					+ e.getMessage(), e);
+	    }
+	    return numberOfUsers;
+	}
+	
+	/** @see org.lamsfoundation.lams.tool.noticeboard.service.INoticeboardService#calculateTotalNumberOfUsers(java.lang.Long) */
+	public int calculateTotalNumberOfUsers(Long toolContentId)
+	{
+	    int totalNumberOfUsers = 0;
+	    try
+	    {
+	        nbContent = retrieveNoticeboard(toolContentId);
+	        List listOfSessionIds = getSessionIdsFromContent(nbContent);
+	        
+	        Iterator i = listOfSessionIds.iterator();
+	        
+	        while(i.hasNext())
+	        {
+	            Long sessionId = (Long)i.next();
+	            int usersInThisSession = getNumberOfUsersInSession(retrieveNoticeboardSession(sessionId));
+	            totalNumberOfUsers = totalNumberOfUsers + usersInThisSession;
+	        }
+	    }
+	    catch (DataAccessException e)
+	    {
+	        throw new NbApplicationException("EXCEPTION: An exception has occurred while calculating the total number of users in tool activity "
+					+ e.getMessage(), e);
+	    }
+	    return totalNumberOfUsers;
+	}
+	
 	/* ===============Methods implemented from ToolContentManager =============== */
 	
 	/** @see org.lamsfoundation.lams.tool.ToolContentManager#copyToolContent(java.lang.Long, java.lang.Long)*/