--- a/flys-client/src/main/java/de/intevation/flys/client/server/StepForwardServiceImpl.java	Fri Apr 08 08:45:15 2011 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/server/StepForwardServiceImpl.java	Fri Apr 08 08:51:28 2011 +0000
@@ -11,6 +11,7 @@
 import de.intevation.artifacts.httpclient.http.HttpClientImpl;
 import de.intevation.artifacts.httpclient.http.response.DocumentResponseHandler;
 
+import de.intevation.flys.client.shared.exceptions.ServerException;
 import de.intevation.flys.client.shared.model.Artifact;
 import de.intevation.flys.client.shared.model.ArtifactDescription;
 import de.intevation.flys.client.shared.model.Data;
@@ -28,11 +29,15 @@
 extends      AdvanceServiceImpl
 implements   StepForwardService
 {
-    /** XPath that points to the result text of a feed or advance operation.*/
-    public static final String XPATH_RESULT = "/art:result/text()";
+    /** XPath that points to the result type of a feed or advance operation.*/
+    public static final String XPATH_RESULT = "/art:result/@art:type";
 
     /** A constant that marks errors.*/
-    public static final String OPERATION_FAILURE = "FAILED";
+    public static final String OPERATION_FAILURE = "FAILURE";
+
+    /** The error message key that is thrown if an error occured while feeding
+     * new data.*/
+    public static final String ERROR_FEED_DATA = "error_feed_data";
 
 
     /**
@@ -45,13 +50,14 @@
      *
      * @return the modified artifact.
      */
-    public Artifact go(String serverUrl, Artifact artifact, Data[] data) {
+    public Artifact go(String serverUrl, Artifact artifact, Data[] data)
+    throws ServerException
+    {
         Artifact afterFeed = feed(serverUrl, artifact, data);
 
         if (afterFeed == null) {
             System.err.println("StepForwardService.feed() - FAILED");
-            // XXX Better handling here!
-            return null;
+            throw new ServerException(ERROR_FEED_DATA);
         }
 
         ArtifactDescription desc = afterFeed.getArtifactDescription();
@@ -78,7 +84,9 @@
      *
      * @return a new artifact parsed from the description of FEED.
      */
-    protected Artifact feed(String serverUrl, Artifact artifact, Data[] data) {
+    protected Artifact feed(String serverUrl, Artifact artifact, Data[] data)
+    throws    ServerException
+    {
         Document feed = ClientProtocolUtils.newFeedDocument(
             artifact.getUuid(),
             artifact.getHash(),
@@ -96,7 +104,7 @@
 
             if (description == null) {
                 System.err.println("StepForwardService.feed() - FAILED");
-                return artifact;
+                throw new ServerException(ERROR_FEED_DATA);
             }
 
             String result = XMLUtils.xpathString(
@@ -108,14 +116,16 @@
                 System.out.println("StepForwardService.feed() - SUCCESS");
                 return (Artifact) new FLYSArtifactCreator().create(description);
             }
+            else if (result != null && result.equals(OPERATION_FAILURE)) {
+                throw new ServerException(ERROR_FEED_DATA);
+            }
         }
         catch (ConnectionException ce) {
             System.err.println(ce.getLocalizedMessage());
         }
 
         System.err.println("StepForwardService.feed() - FAILED");
-
-        return artifact;
+        throw new ServerException(ERROR_FEED_DATA);
     }