diff --git a/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/DomainObjectFactory.java b/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/DomainObjectFactory.java
index b0540dec3c5..a61df1e749f 100755
--- a/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/DomainObjectFactory.java
+++ b/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/DomainObjectFactory.java
@@ -28,10 +28,19 @@ public interface DomainObjectFactory {
 
     RaceIdentifier loadRaceIdentifier(DBObject dbObject);
     
+    /**
+     * @return The group with the name <code>name</code>, or <code>null</code> if no such group exists.
+     */
     LeaderboardGroup loadLeaderboardGroup(String name);
     
+    /**
+     * @return All groups in the database.
+     */
     Iterable<LeaderboardGroup> getAllLeaderboardGroups();
     
+    /**
+     * @return All leaderboards in the database, which aren't contained by a leaderboard group
+     */
     Iterable<Leaderboard> getLeaderboardsNotInGroup();
 
 }
diff --git a/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/MongoObjectFactory.java b/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/MongoObjectFactory.java
index 9dec8f8f312..742620d580b 100755
--- a/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/MongoObjectFactory.java
+++ b/java/com.sap.sailing.domain.persistence/src/com/sap/sailing/domain/persistence/MongoObjectFactory.java
@@ -43,10 +43,20 @@ public interface MongoObjectFactory {
 
     void storeRaceIdentifier(RaceIdentifier raceIdentifier, DBObject dbObject);
     
+    /**
+     * Stores the group, if it doesn't exist or updates it.<br />
+     * Leaderboards in the group, which aren't stored in the database, will be stored.
+     */
     void storeLeaderboardGroup(LeaderboardGroup leaderboardGroup);
     
+    /**
+     * Removes the group with the name <code>groupName</code> from the database.
+     */
     void removeLeaderboardGroup(String groupName);
-    
+
+    /**
+     * Renames the group with the name <code>oldName</code>.
+     */
     void renameLeaderboardGroup(String oldName, String newName);
 
 }