diff --git a/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/shared/api/v1/dto/SizeCriterion.java b/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/shared/api/v1/dto/SizeCriterion.java
index 5127b67af23b1e2c3f587f782936eefb9c555e87..c8cbcedc26e89f6f6bc5d506db05d1920ebc2a71 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/shared/api/v1/dto/SizeCriterion.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/shared/api/v1/dto/SizeCriterion.java
@@ -130,10 +130,8 @@ public class SizeCriterion implements IImageSetSelectionCriterion
             }
         };
 
-        void filter(int width, int height, List<IImageSetMetaData> imageMetaData,
-                List<IImageSetMetaData> filteredImageMetaData)
-        {
-        }
+        abstract void filter(int width, int height, List<IImageSetMetaData> imageMetaData,
+                List<IImageSetMetaData> filteredImageMetaData);
     }
 
     private static final Comparator<IImageSetMetaData> SIZE_COMPARATOR =