Accessible childRowToOs(int childID) {
    if (childID == ACC.CHILDID_SELF) {
      return tableAccessible;
    }

    /* Check cache for childID, if found, return corresponding osChildID. */
    AccessibleTableRow childRef =
        (AccessibleTableRow) childRowToIdMap.get(Integer.valueOf(childID));

    if (childRef == null) {
      childRef = new AccessibleTableRow(tableAccessible, childID);
      childRowToIdMap.put(Integer.valueOf(childID), childRef);
    }

    return childRef;
  }