Merge branch 'master' into bug4009

java/com.sap.sse.common/src/com/sap/sse/common/Util.java

@@ -397,9 +397,27 @@ public class Util {
      * made. This is the caller's obligation.
      */
     public static <K, V> void addToValueSet(Map<K, Set<V>> map, K key, V value) {
+        addToValueSet(map, key, value, new ValueSetConstructor<V>() {
+            @Override
+            public Set<V> createSet() {
+                return new HashSet<V>();
+            }
+        });
+    }
+
+    public static interface ValueSetConstructor<T> {
+        Set<T> createSet();
+    }
+    
+    /**
+     * Ensures that a {@link Set Set&lt;V&gt;} is contained in {@code map} for {@code key} and
+     * then adds {@code value} to that set. No synchronization / concurrency control effort is
+     * made. This is the caller's obligation.
+     */
+    public static <K, V> void addToValueSet(Map<K, Set<V>> map, K key, V value, ValueSetConstructor<V> setConstructor) {
         Set<V> set = map.get(key);
         if (set == null) {
-            set = new HashSet<V>();
+            set = setConstructor.createSet();
             map.put(key, set);
         }
         set.add(value);