Index: trunk/src/org/openstreetmap/josm/io/OsmImporter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/OsmImporter.java	(revision 4686)
+++ trunk/src/org/openstreetmap/josm/io/OsmImporter.java	(revision 4687)
@@ -67,7 +67,11 @@
      */
     public void loadLayer(InputStream in, final File associatedFile, final String layerName, ProgressMonitor progressMonitor) throws IllegalDataException {
-        final DataSet dataSet = OsmReader.parseDataSet(in, progressMonitor);
+        final DataSet dataSet = parseDataSet(in, progressMonitor);
         layer = createLayer(dataSet, associatedFile, layerName);
         postLayerTask = createPostLayerTask(dataSet, associatedFile, layerName);
+    }
+    
+    protected DataSet parseDataSet(InputStream in, ProgressMonitor progressMonitor) throws IllegalDataException {
+        return OsmReader.parseDataSet(in, progressMonitor);
     }