--- a/flys-client/src/main/java/de/intevation/flys/client/client/ui/CollectionView.java	Fri Mar 18 13:45:34 2011 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/client/ui/CollectionView.java	Mon Mar 21 08:28:02 2011 +0000
@@ -29,13 +29,18 @@
 import de.intevation.flys.client.client.FLYSMessages;
 import de.intevation.flys.client.client.event.HasCollectionChangeHandlers;
 import de.intevation.flys.client.client.event.HasParameterChangeHandler;
+import de.intevation.flys.client.client.event.HasStepBackHandlers;
 import de.intevation.flys.client.client.event.HasStepForwardHandlers;
 import de.intevation.flys.client.client.event.CollectionChangeEvent;
 import de.intevation.flys.client.client.event.CollectionChangeHandler;
 import de.intevation.flys.client.client.event.ParameterChangeEvent;
 import de.intevation.flys.client.client.event.ParameterChangeHandler;
+import de.intevation.flys.client.client.event.StepBackEvent;
+import de.intevation.flys.client.client.event.StepBackHandler;
 import de.intevation.flys.client.client.event.StepForwardEvent;
 import de.intevation.flys.client.client.event.StepForwardHandler;
+import de.intevation.flys.client.client.services.AdvanceService;
+import de.intevation.flys.client.client.services.AdvanceServiceAsync;
 import de.intevation.flys.client.client.services.ArtifactService;
 import de.intevation.flys.client.client.services.ArtifactServiceAsync;
 import de.intevation.flys.client.client.services.StepForwardService;
@@ -52,7 +57,7 @@
 extends      Window
 implements   CollectionChangeHandler, HasCollectionChangeHandlers,
              HasParameterChangeHandler, ParameterChangeHandler,
-             StepForwardHandler
+             StepForwardHandler, StepBackHandler
 {
     /** The ArtifactService used to communicate with the Artifact server. */
     protected ArtifactServiceAsync artifactService =
@@ -62,6 +67,10 @@
     protected StepForwardServiceAsync forwardService =
         GWT.create(StepForwardService.class);
 
+    /** The StepForwardService used to put data into an existing artifact. */
+    protected AdvanceServiceAsync advanceService =
+        GWT.create(AdvanceService.class);
+
     /** The ArtifactService used to communicate with the Artifact server. */
     protected CreateCollectionServiceAsync createCollectionService =
         GWT.create(CreateCollectionService.class);
@@ -111,7 +120,7 @@
 
         this.tabs              = new TabSet();
         this.parameterTab      = new Tab(messages.winfo());
-        this.parameterList     = new ParameterList();
+        this.parameterList     = new ParameterList(this);
         this.handlers          = new ArrayList<CollectionChangeHandler>();
         this.parameterHandlers = new ArrayList<ParameterChangeHandler>();
         this.layout            = new VLayout();
@@ -357,6 +366,32 @@
 
 
     /**
+     * This method is used to call the ADVANCE service to go back to a previous
+     * state.
+     *
+     * @param e The StepBackEvent that holds the identifier of the target state.
+     */
+    public void onStepBack(StepBackEvent e) {
+        final String target    = e.getTarget();
+        final String serverUrl = Config.getInstance().getServerUrl();
+
+        advanceService.advance(serverUrl, artifact, target,
+            new AsyncCallback<Artifact>() {
+                public void onFailure(Throwable caught) {
+                    GWT.log("Could not go back to '" + target + "'");
+                    GWT.log(caught.getMessage());
+                }
+
+                public void onSuccess(Artifact artifact) {
+                    GWT.log("Successfully step back to '" + target + "'");
+                    setArtifact(artifact);
+                }
+            }
+        );
+    }
+
+
+    /**
      * This method is called if the user clicks on the 'next' button to advance
      * to the next state.
      *
@@ -394,8 +429,8 @@
             String uiProvider   = currentData.getUIProvider();
             UIProvider provider = UIProviderFactory.getProvider(uiProvider);
 
-            HasStepForwardHandlers handler = (HasStepForwardHandlers) provider;
-            handler.addStepForwardHandler(this);
+            ((HasStepForwardHandlers) provider).addStepForwardHandler(this);
+            ((HasStepBackHandlers) provider).addStepBackHandler(this);
 
             parameterList.setCurrentData(currentData, provider);
         }