--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WQSelect.java	Tue May 24 12:58:55 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WQSelect.java	Tue May 24 13:24:24 2011 +0000
@@ -271,23 +271,33 @@
     throws    IllegalArgumentException
     {
         logger.debug("WQSelect.validateRange");
+        FLYSArtifact flys = (FLYSArtifact) artifact;
 
-        String mode = (String) data.get(WQ_MODE).getValue();
+        StateData data = flys.getData(WQ_MODE);
+        String    mode = data != null ? (String) data.getValue() : null;
         logger.debug("WQ Mode: " + mode);
 
-        String fromStr = (String) data.get(WQ_FROM).getValue();
-        String toStr   = (String) data.get(WQ_TO).getValue();
-        String stepStr = (String) data.get(WQ_STEP).getValue();
+        if (mode == null || mode.length() == 0) {
+            throw new IllegalArgumentException("error_feed_invalid_wq_mode");
+        }
+
+        StateData dFrom = flys.getData(WQ_FROM);
+        StateData dTo   = flys.getData(WQ_TO);
+        StateData dStep = flys.getData(WQ_STEP);
+
+        String fromStr = dFrom != null ? (String) dFrom.getValue() : null;
+        String toStr   = dTo != null ? (String) dTo.getValue() : null;
+        String stepStr = dStep != null ? (String) dStep.getValue() : null;
 
         if (fromStr == null || toStr == null || stepStr == null) {
             throw new IllegalArgumentException("error_empty_state");
         }
 
-        double from = Double.parseDouble(fromStr);
-        double to   = Double.parseDouble(toStr);
-        double step = Double.parseDouble(stepStr);
+        try {
+            double from = Double.parseDouble(fromStr);
+            double to   = Double.parseDouble(toStr);
+            double step = Double.parseDouble(stepStr);
 
-        try {
             if (mode != null && mode.trim().toLowerCase().equals("w")) {
                 return validateW(artifact, context, from, to, step);
             }