--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Tue Sep 27 07:41:21 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Tue Sep 27 09:35:18 2011 +0000
@@ -1,26 +1,28 @@
 package de.intevation.flys.artifacts.states;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import org.apache.log4j.Logger;
 
-import de.intevation.artifacts.CallContext;
+import de.intevation.artifactdatabase.state.Facet;
+import de.intevation.artifactdatabase.data.StateData;
 
-import de.intevation.artifactdatabase.state.Facet;
-
+import de.intevation.artifacts.CallContext;
 import de.intevation.artifacts.Artifact;
 import de.intevation.flys.artifacts.FLYSArtifact;
 import de.intevation.flys.artifacts.WINFOArtifact;
 
 import de.intevation.flys.artifacts.math.WKmsOperation;
 
+import de.intevation.flys.artifacts.model.CalculationResult;
+import de.intevation.flys.artifacts.model.DataFacet;
+import de.intevation.flys.artifacts.model.DifferenceCurveFacet;
 import de.intevation.flys.artifacts.model.FacetTypes;
+import de.intevation.flys.artifacts.model.WaterlevelFacet;
 import de.intevation.flys.artifacts.model.WKms;
 import de.intevation.flys.artifacts.model.WQKms;
 
-import de.intevation.flys.artifacts.model.DataFacet;
-import de.intevation.artifactdatabase.data.StateData;
-
 import de.intevation.flys.utils.FLYSUtils;
 
 
@@ -61,7 +63,9 @@
     }
 
 
-
+    /**
+     * Return List of WKms that are difference of pairs.
+     */
     @Override
     public Object computeAdvance(
         FLYSArtifact artifact,
@@ -90,7 +94,7 @@
             ;
         }
 
-        WKms wkms = null;
+        List<WKms> wkmss = new ArrayList<WKms>();
 
         for(int i = 0; i < datas.length /2; i++) {
             String uuid1 = WaterlevelSelectState.strip(datas[i+0]).split(";")[0];
@@ -110,27 +114,33 @@
                 logger.warn("One of the artifacts (2) for diff calculation could not be loaded");
             }
             // TODO: Issue of multiple results in calculation
-            //WKms wkms = null;
             String facetName = "diff ()";
     
             if (flys1 != null && flys2 != null) {
                 // TODO Also check size.
                 // TODO Also need index of wqkms.
-                WQKms[] minuend = (WQKms[]) flys1.getWaterlevelData().getData();
-                WQKms[] subtrahend = (WQKms[]) flys2.getWaterlevelData().getData();
+                WQKms[] minuend    = (WQKms[]) flys1.getWaterlevelData().
+                                                     getData();
+                WQKms[] subtrahend = (WQKms[]) flys2.getWaterlevelData().
+                                                     getData();
 
                 if (datas.length > 2) {
                     logger.error("Cannot keep more than one calculation.");
                 }
-                wkms = WKmsOperation.SUBTRACTION.operate(minuend[0], subtrahend[0]);
-                facetName = "W ("+minuend[0].getName() + ") - W (" + subtrahend[0].getName()+")";
+                facetName = "W (" + minuend[0].getName() + ") - W (" + subtrahend[0].getName() + ")";
+                WKms wkms = WKmsOperation.SUBTRACTION.operate(minuend[0], subtrahend[0]);
+                wkms.setName(facetName);
+                wkmss.add(wkms);
                 logger.debug("WKMSSubtraction happened");
             }
     
             if (facets != null) {
                 // TODO: pass computetype and state id.
                 //, ComputeType.ADVANCE, getID(), hash));
-                facets.add(new DataFacet(W_DIFFERENCES, facetName));
+                //facets.add(new DataFacet(W_DIFFERENCES, facetName));
+                facets.add(new DifferenceCurveFacet(i, W_DIFFERENCES, facetName,
+                    ComputeType.ADVANCE, id, hash));
+                //facets.add(new WaterlevelFacet
                 facets.add(new DataFacet(CSV, "CSV data"));
             }
             else {
@@ -138,7 +148,10 @@
             }
         }
 
-        return wkms;
+        CalculationResult result = new CalculationResult();
+        WKms[] diffs = wkmss.toArray(new WKms[wkmss.size()]);
+        result.setData(diffs);
+        return result;
     }
 }
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