Index: /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/treeifc/DefaultTaskTraversingVisitor.java
===================================================================
--- /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/treeifc/DefaultTaskTraversingVisitor.java	(revision 1409)
+++ /trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/treeifc/DefaultTaskTraversingVisitor.java	(revision 1409)
@@ -0,0 +1,113 @@
+//   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.tasktrees.treeifc;
+
+/**
+ * <p>
+ * Default implementation for a task visitor performing a traversal of the task
+ * </p>
+ * 
+ * @author Patrick Harms
+ */
+public class DefaultTaskTraversingVisitor implements ITaskVisitor {
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(IEventTask)
+     */
+    @Override
+    public void visit(IEventTask eventTask) {
+        // do nothing
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(IIteration)
+     */
+    @Override
+    public void visit(IIteration iteration) {
+        visit((IMarkingTemporalRelationship) iteration);
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(IOptional)
+     */
+    @Override
+    public void visit(IOptional optional) {
+        visit((IMarkingTemporalRelationship) optional);
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(ISelection)
+     */
+    @Override
+    public void visit(ISelection selection) {
+        visit((IStructuringTemporalRelationship) selection);
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(ISequence)
+     */
+    @Override
+    public void visit(ISequence sequence) {
+        visit((IStructuringTemporalRelationship) sequence);
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor#visit(ITask)
+     */
+    @Override
+    public void visit(ITask task) {
+        if (task instanceof IEventTask) {
+            visit((IEventTask) task);
+        }
+        else if (task instanceof IIteration) {
+            visit((IIteration) task);
+        }
+        else if (task instanceof IOptional) {
+            visit((IOptional) task);
+        }
+        else if (task instanceof ISelection) {
+            visit((ISelection) task);
+        }
+        else if (task instanceof ISequence) {
+            visit((ISequence) task);
+        }
+    }
+
+    /**
+     * <p>
+     * common implementation for traversing a structuring temporal relationship 
+     * </p>
+     * 
+     * @param relationship the structuring temporal relationship to be traversed
+     */
+    public void visit(IStructuringTemporalRelationship relationship) {
+        for (ITask child : relationship.getChildren()) {
+            child.accept(this);
+        }
+    }
+
+    /**
+     * <p>
+     * common implementation for traversing a marking temporal relationship 
+     * </p>
+     * 
+     * @param relationship the marking temporal relationship to be traversed
+     */
+    public void visit(IMarkingTemporalRelationship relationship) {
+        if (relationship.getMarkedTask() != null) {
+            relationship.getMarkedTask().accept(this);
+        }
+    }
+}