Index: /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModelHelpers.java
===================================================================
--- /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModelHelpers.java	(revision 1399)
+++ /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModelHelpers.java	(revision 1399)
@@ -0,0 +1,121 @@
+//   Copyright 2012 Georg-August-Universität Göttingen, Germany
+//
+//   Licensed under the Apache License, Version 2.0 (the "License");
+//   you may not use this file except in compliance with the License.
+//   You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+
+package de.ugoe.cs.autoquest.eventcore.guimodel;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * <p>
+ * convenience methods for working with GUI elements. E.g. to determine, if two GUI elements have a
+ * common parent on their parent hierarchies.
+ * </p>
+ * 
+ * @author Patrick Harms, Ralph Krimmel
+ */
+public class GUIModelHelpers {
+
+    /**
+     * <p>
+     * return a common denominator for the provided list of GUI elements, i.e. a GUI element, that
+     * is part of the parent GUI hiearchy of all GUI elements in the list. If there is no common
+     * denominator, the method returns null.
+     * </p>
+     * 
+     * @param guiElements the GUI elements to get the common denominator of
+     */
+    public static IGUIElement getCommonDenominator(IGUIElement... guiElements) {
+        IGUIElement commonDenominator = null;
+
+        if (guiElements.length > 0) {
+            List<IGUIElement> commonDenominatorPath = new ArrayList<IGUIElement>();
+
+            // create a reference list using the first GUI element
+            IGUIElement guiElement = guiElements[0];
+            while (guiElement != null) {
+                commonDenominatorPath.add(0, guiElement);
+                guiElement = guiElement.getParent();
+            }
+
+            if (commonDenominatorPath.size() == 0) {
+                return null;
+            }
+
+            // for each other GUI element, check the reference list for the first element in the
+            // path, that is not common to the current one, and delete it as well as it subsequent
+            // siblings
+            List<IGUIElement> currentPath = new ArrayList<IGUIElement>();
+            for (int i = 1; i < guiElements.length; i++) {
+                currentPath.clear();
+                guiElement = guiElements[i];
+                while (guiElement != null) {
+                    currentPath.add(0, guiElement);
+                    guiElement = guiElement.getParent();
+                }
+
+                // determine the index of the first unequal path element
+                int index = 0;
+                while ((index < commonDenominatorPath.size()) && (index < currentPath.size()) &&
+                        commonDenominatorPath.get(index).equals(currentPath.get(index)))
+                {
+                    index++;
+                }
+
+                // remove all elements from the common denonimator path, that do
+                // not match
+                while (index < commonDenominatorPath.size()) {
+                    commonDenominatorPath.remove(index);
+                }
+            }
+
+            if (commonDenominatorPath.size() > 0) {
+                commonDenominator = commonDenominatorPath.get(commonDenominatorPath.size() - 1);
+            }
+        }
+        
+        return commonDenominator;
+    }
+
+    /**
+     * <p>
+     * determines the number of hops through the GUI element hierarchy to get from one GUI element
+     * to another.
+     * </p>
+     *
+     * @param first  the first GUI element, i.e., the start in the hierarchy
+     * @param second the second GUI element, i.e., the end in the hierarchy
+     * 
+     * @return the number of required hops to get from the first GUI element to the second,
+     *         INTEGER.MAX_INT if the GUI elements do not share a common parent
+     */
+    public static int getDistance(IGUIElement first, IGUIElement second) {
+        int hopcount = 0;
+        
+        IGUIElement commonDenominator = getCommonDenominator(first, second);
+
+        while (!(first.equals(commonDenominator))) {
+            first = first.getParent();
+            hopcount++;
+        }
+
+        while (!(second.equals(commonDenominator))) {
+            second = second.getParent();
+            hopcount++;
+        }
+
+        return hopcount;
+    }
+
+}