--- a/flys-artifacts/ChangeLog	Tue Oct 18 15:22:33 2011 +0000
+++ b/flys-artifacts/ChangeLog	Tue Oct 18 15:26:14 2011 +0000
@@ -1,3 +1,11 @@
+2011-10-18  Felix Wolfsteller	<felix.wolfsteller@intevation.de>
+
+	Refactored WDifferencesState to deal with WKms of different
+	artifacts (in principle).
+
+	* src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java:
+	  Handle case where WKms come from StaticWKmsArtifact.
+
 2011-10-18  Felix Wolfsteller	<felix.wolfsteller@intevation.de>
 
 	Adjusted Datacage-Configuration to fetch "extra longitudinal...."

--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Tue Oct 18 15:22:33 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Tue Oct 18 15:26:14 2011 +0000
@@ -11,6 +11,7 @@
 import de.intevation.artifacts.CallContext;
 import de.intevation.artifacts.Artifact;
 import de.intevation.flys.artifacts.FLYSArtifact;
+import de.intevation.flys.artifacts.StaticWKmsArtifact;
 import de.intevation.flys.artifacts.WINFOArtifact;
 
 import de.intevation.flys.artifacts.math.WKmsOperation;
@@ -63,6 +64,44 @@
     }
 
 
+    protected WKms getWKms(String mingle, CallContext context) {
+        String[] def  = mingle.split(";");
+        String   uuid = def[0];
+        String   name = def[1];
+        int      idx  = Integer.parseInt(def[2]);
+
+        if (name.startsWith("staticwkms")) {
+            StaticWKmsArtifact staticWKms =
+                (StaticWKmsArtifact) FLYSUtils.getArtifact(
+                    uuid,
+                    context);
+            logger.debug("WDifferencesState obtain data from StaticWKms");
+            WKms wkms = staticWKms.getWKms(idx);
+            if (wkms == null)
+                logger.error("No WKms from artifact.");
+            return wkms;
+        }
+    
+        WINFOArtifact flys = (WINFOArtifact) FLYSUtils.getArtifact(
+            uuid,
+            context);
+
+        if (flys == null) {
+            logger.warn("One of the artifacts (1) for diff calculation could not be loaded");
+            return null;
+        }
+        else{
+            WQKms[] wqkms = (WQKms[]) flys.getWaterlevelData().
+                                              getData();
+            if (wqkms == null)
+            logger.warn("not  waterlevels in artifact");
+            else if (wqkms.length < idx)
+            logger.warn("not enough waterlevels in artifact");
+            return wqkms[idx];
+        }
+    }
+
+
     /**
      * Return CalculationResult with Array of WKms that are difference of
      * Waterlevels. Add respective facets (DifferencesCurveFacet, DataFacet).
@@ -75,13 +114,14 @@
         List<Facet>  facets,
         Object       old
     ) {
-        WINFOArtifact winfo = (WINFOArtifact)artifact;
+        WINFOArtifact winfo = (WINFOArtifact) artifact;
         String id = getID();
 
         // Load the Artifacts/facets that we want to subtract and display.
         // Expected format is:
         // [42537f1e-3522-42ef-8968-635b03d8e9c6;longitudinal_section.w;0]#[1231f2-....]
         String diffids = winfo.getDataAsString("diffids");
+        logger.debug("WDifferencesState has: " + diffids);
         String datas[] = diffids.split("#");
 
         // Validate the Data-Strings.
@@ -101,39 +141,18 @@
         for(int i = 0; i < datas.length; i+=2) {
             // e.g.:
             // 42537f1e-3522-42ef-8968-635b03d8e9c6;longitudinal_section.w;1
-            String[] def1  = StringUtil.unbracket(datas[i+0]).split(";");
-            String[] def2  = StringUtil.unbracket(datas[i+1]).split(";");
-            String   uuid1 = def1[0];
-            String   uuid2 = def2[0];
-            int      idx1  = Integer.parseInt(def1[2]);
-            int      idx2  = Integer.parseInt(def2[2]);
-    
-            WINFOArtifact flys1 = (WINFOArtifact) FLYSUtils.getArtifact(
-                uuid1,
-                context);
-            WINFOArtifact flys2 = (WINFOArtifact) FLYSUtils.getArtifact(
-                uuid2,
+            WKms minuendWKms = getWKms(StringUtil.unbracket(datas[i+0]),
                 context);
-    
-            if (flys1 == null) {
-                logger.warn("One of the artifacts (1) for diff calculation could not be loaded");
-            }
-            if (flys2 == null) {
-                logger.warn("One of the artifacts (2) for diff calculation could not be loaded");
-            }
-            // TODO: Issue of multiple results in calculation
+            WKms subtrahendWKms = getWKms(StringUtil.unbracket(datas[i+1]),
+                context);
+
             String facetName = "diff ()";
-    
-            if (flys1 != null && flys2 != null) {
-                WQKms[] minuend    = (WQKms[]) flys1.getWaterlevelData().
-                                                     getData();
-                WQKms[] subtrahend = (WQKms[]) flys2.getWaterlevelData().
-                                                     getData();
 
-                facetName = StringUtil.wWrap(minuend[idx1].getName()) 
-                    + " - " + StringUtil.wWrap(subtrahend[idx2].getName());
-                WKms wkms = WKmsOperation.SUBTRACTION.operate(minuend[idx1],
-                     subtrahend[idx2]);
+            if (minuendWKms != null && subtrahendWKms != null) {
+                facetName = StringUtil.wWrap(minuendWKms.getName()) 
+                    + " - " + StringUtil.wWrap(subtrahendWKms.getName());
+                WKms wkms = WKmsOperation.SUBTRACTION.operate(minuendWKms,
+                     subtrahendWKms);
                 wkms.setName(facetName);
                 wkmss.add(wkms);
                 logger.debug("WKMSSubtraction happened");
@@ -143,6 +162,7 @@
                 facets.add(new DifferenceCurveFacet(i/2, W_DIFFERENCES, facetName,
                     ComputeType.ADVANCE, id, hash));
                 facets.add(new DataFacet(CSV, "CSV data"));
+                logger.debug("Adding facets in WDifferencesState.");
             }
             else {
                 logger.debug("Not adding facets in WDifferencesState.");