--- a/flys-artifacts/ChangeLog	Mon Sep 26 13:10:40 2011 +0000
+++ b/flys-artifacts/ChangeLog	Mon Sep 26 13:17:55 2011 +0000
@@ -1,3 +1,14 @@
+2011-09-26  Felix Wolfsteller <felix.wolfsteller@intevation.de>
+
+ Add positional-conflict-awareness when merging Facets for a
+ FLYSArtifactCollection. First come first serve.
+
+	* src/main/java/de/intevation/flys/collections/AttributeWriter.java:
+	  (writeFacets): First, sort incoming facets into 2 groups:
+	  "genuinely new" and "already there", then for each new check
+	  whether the position is already taken. If so, push "up" (position++)
+	  until no conflict exists anymore.
+
 2011-09-26  Ingo Weinzierl <ingo@intevation.de>
 
 	flys/issue296 (Karte: Bezeichnungen verbessern)
@@ -11,7 +22,7 @@
 	  src/main/resources/messages_de.properties: Added strings for the wsplgen
 	  and barriers WMS layers.
 
-2011-09-23  Felix Wolfsteller <felix.wolfsteller@intevation.de>
+2011-09-26  Felix Wolfsteller <felix.wolfsteller@intevation.de>
 
  Fix (revert) access to position in ManagedDomFacet.
 

--- a/flys-artifacts/src/main/java/de/intevation/flys/collections/AttributeWriter.java	Mon Sep 26 13:10:40 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/collections/AttributeWriter.java	Mon Sep 26 13:17:55 2011 +0000
@@ -1,5 +1,6 @@
 package de.intevation.flys.collections;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
@@ -129,11 +130,42 @@
 
         // Add all new Facets either in their old state or (if really
         // new) as they are.
+        List<ManagedFacet> currentFacets      = new ArrayList<ManagedFacet>();
+        List<ManagedFacet> genuinelyNewFacets = new ArrayList<ManagedFacet>();
         for (int i = 0; i < num; i++) {
             ManagedFacet facet = (ManagedFacet) newFacets.get(i);
 
             ManagedFacet picked = pickFacet(facet, oldFacets);
-            Node         node   = picked.toXML(doc);
+            if (facet.equals(picked)) {
+                genuinelyNewFacets.add(picked);
+            }
+            else {
+                currentFacets.add(picked);
+            }
+        }
+
+        // For each genuinely new Facet check positional conflicts.
+        for (ManagedFacet newMF: genuinelyNewFacets) {
+            boolean conflicts = true;
+            // Loop until all conflicts resolved.
+            while (conflicts) {
+                conflicts = false;
+                for (ManagedFacet oldMF: currentFacets) {
+                    if (newMF.getPosition() == oldMF.getPosition()) {
+                        conflicts = true;
+                        logger.debug("Positional conflict while merging " +
+                            "facets, pushing newest facet 1 up ("+newMF.getPosition()+")");
+                        newMF.setPosition(newMF.getPosition() + 1);
+                        break;
+                    }
+                }
+            }
+            currentFacets.add(newMF);
+        }
+
+        // Now add all facets.
+        for (ManagedFacet oldMF: currentFacets) {
+            Node node = oldMF.toXML(doc);
             if (node != null) {
                 output.appendChild(node);
             }