/** Adds a cheatsheet collection to this collection. */
 public void add(IAdaptable a) {
   if (a instanceof CheatSheetElement) {
     cheatsheets.add(a);
   } else {
     childCollections.add(a);
   }
 }
 /** For debugging purposes. */
 public String toString() {
   StringBuffer buf = new StringBuffer("CheatSheetCollection, "); // $NON-NLS-1$
   buf.append(childCollections.size());
   buf.append(" children, "); // $NON-NLS-1$
   buf.append(cheatsheets.size());
   buf.append(" cheatsheets"); // $NON-NLS-1$
   return buf.toString();
 }
 /** Returns true if this element has no children and no cheatsheets. */
 public boolean isEmpty() {
   return childCollections.size() == 0 && cheatsheets.size() == 0;
 }
 /** Returns this collection element's associated collection of cheatsheets. */
 public Object[] getCheatSheets() {
   return cheatsheets.getChildren();
 }