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diff --git a/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/SelectionUtils.java b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/SelectionUtils.java
new file mode 100644
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+++ b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/SelectionUtils.java
@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management
+ * in Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.utils.datastructures;
+
+import java.util.Collection;
+import java.util.ConcurrentModificationException;
+
+public class SelectionUtils {
+
+    public static <T> T getSingle(Collection<T> collection) {
+        if(collection.size() != 1)
+            throw new RuntimeException("Size of the collection is not one.");
+        for(T obj : collection)
+            return obj;
+        throw new ConcurrentModificationException("collection was emptied before iteration");
+    }
+    
+    public static <T> T getAtMostOne(Collection<T> collection) {
+        if(collection.size() > 1)
+            throw new RuntimeException("Size of the collection is greater than one.");
+        for(T obj : collection)
+            return obj;
+        return null;
+    }
+
+}