}
if (indexNameFrom == null || indexNameTo == null) {
throw new RuntimeException("no such index for class specified");
}
final ObjectIndex indexFrom = (ObjectIndex)m_jispIndexes.get(indexNameFrom);
final ObjectIndex indexTo = (ObjectIndex)m_jispIndexes.get(indexNameTo);
final Class indexTypeFrom = (Class)m_jispIndexTypes.get(indexNameFrom);
final Class indexTypeTo = (Class)m_jispIndexTypes.get(indexNameTo);
if (!(indexFrom instanceof BTreeIndex) || !(indexTo instanceof BTreeIndex)) {
throw new RuntimeException("from A to index must both be of type BTreeIndex");