Index: /trunk/autoquest-core-usability-evaluation/src/main/java/de/ugoe/cs/autoquest/usability/util/NullTask.java
===================================================================
--- /trunk/autoquest-core-usability-evaluation/src/main/java/de/ugoe/cs/autoquest/usability/util/NullTask.java	(revision 1163)
+++ /trunk/autoquest-core-usability-evaluation/src/main/java/de/ugoe/cs/autoquest/usability/util/NullTask.java	(revision 1163)
@@ -0,0 +1,79 @@
+//   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.usability.util;
+
+import org.apache.commons.lang.StringUtils;
+
+import de.ugoe.cs.autoquest.tasktrees.treeifc.ITask;
+import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskVisitor;
+
+/**
+ * <p>
+ * TODO comment
+ * </p>
+ * 
+ * @author Alexander Deicke
+ */
+public class NullTask implements ITask {
+
+    /**  */
+    private static final long serialVersionUID = 1236779392413787860L;
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITask#getId()
+     */
+    @Override
+    public int getId() {
+        return -1;
+    }
+    
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode#getName()
+     */
+    public String getName() {
+        return StringUtils.EMPTY;
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode#getDescription()
+     */
+    public String getDescription() {
+        return StringUtils.EMPTY;
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode#equals(de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode)
+     */
+    public boolean equals(ITask task) {
+        return false;
+    }
+    
+    /* (non-Javadoc)
+     * @see java.lang.Object#clone()
+     */
+    @Override
+    public NullTask clone() {
+        return (NullTask) this;
+    }
+
+    /* (non-Javadoc)
+     * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode#accept(de.ugoe.cs.autoquest.tasktrees.treeifc.NodeVisitor)
+     */
+    public void accept(ITaskVisitor visitor) {
+        // do nothing
+    }
+    
+}
+