1 files changed, 9 insertions, 7 deletions
diff --git a/src/main/java/com/c2kernel/collection/AggregationInstance.java b/src/main/java/com/c2kernel/collection/AggregationInstance.java
index e01fe12..2de6b7f 100644
--- a/src/main/java/com/c2kernel/collection/AggregationInstance.java
+++ b/src/main/java/com/c2kernel/collection/AggregationInstance.java
@@ -21,10 +21,12 @@
 package com.c2kernel.collection;
 
 /**
- * @version $Revision: 1.30 $ $Date: 2003/06/04 13:21:24 $
- * @author  $Author: abranson $
+ * Instance of an Aggregation. Unlike in the description, Items may only be 
+ * assigned to one slot.
  */
 
+import com.c2kernel.common.InvalidCollectionModification;
+import com.c2kernel.common.ObjectAlreadyExists;
 import com.c2kernel.graph.model.GraphPoint;
 import com.c2kernel.lookup.ItemPath;
 import com.c2kernel.utils.CastorHashMap;
@@ -45,20 +47,20 @@ public class AggregationInstance extends Aggregation
 
     @Override
 	public AggregationMember addMember(ItemPath itemPath, CastorHashMap props, String classProps)
-        throws MembershipException
+        throws InvalidCollectionModification, ObjectAlreadyExists
     {
         if( itemPath != null && exists(itemPath))
-            throw new MembershipException(itemPath+" already exists in this collection.");
+            throw new ObjectAlreadyExists(itemPath+" already exists in this collection.");
         else
             return super.addMember(itemPath, props, classProps);
     }
 
-    @Override
+	@Override
 	public AggregationMember addMember(ItemPath itemPath, CastorHashMap props, String classProps, GraphPoint location, int w, int h)
-        throws MembershipException
+        throws InvalidCollectionModification, ObjectAlreadyExists
     {
         if( itemPath != null && exists(itemPath))
-			throw new MembershipException(itemPath+" already exists in this collection.");
+			throw new ObjectAlreadyExists(itemPath+" already exists in this collection.");
         else
             return super.addMember(itemPath, props, classProps, location, w, h);
     }