--- a/dwtx/core/commands/operations/AbstractOperation.d	Mon May 19 13:41:06 2008 +0200
+++ b/dwtx/core/commands/operations/AbstractOperation.d	Thu May 22 01:36:46 2008 +0200
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2005, 2006 IBM Corporation and others.
+ * Copyright (c) 2005, 2008 IBM Corporation and others.
  * 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
@@ -51,9 +51,11 @@
      * Construct an operation that has the specified label.
      *
      * @param label
-     *            the label to be used for the operation.
+     *            the label to be used for the operation. Should never be
+     *            <code>null</code>.
      */
     public this(String label) {
+        Assert.isNotNull(label);
         this.label = label;
         contexts = new ArraySeq!(IUndoContext);
     }
@@ -143,7 +145,8 @@
      * Set the label of the operation to the specified name.
      *
      * @param name
-     *            the string to be used for the label.
+     *            the string to be used for the label. Should never be
+     *            <code>null</code>.
      */
     public void setLabel(String name) {
         label = name;