* @param array input array. All elements of argument array must be
* instances of {@link Step}
* @return an array of {@link Step}s
*/
private Step[] toStepArray(Object[] array) {
Step stepArray[] = null;
if (array != null) {
stepArray = new Step[array.length];
for (int i = 0; i < stepArray.length; i++) {
stepArray[i] = (Step) array[i];
}