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