JSTL: How to get previous and next iteration elements of Map?

<c:forEach items="${ctsDictionary}" var="cts" varStatus="status">

 <tr>
    <td align="center">
         PREV: <c:out value='${ctsDictionary[status.index-1].value.clock_no}'/>           CURR: <c:out value='${cts.value.clock_no}'/> 
          NEXT: <c:out value='${ctsDictionary[status.index+1].value.clock_no}'/>                    </td>
                </tr>   

            </c:forEach>