ContentType content = OVFEnvelopeUtils.getTopLevelVirtualSystemContent(envelope);
if (content instanceof VirtualSystemCollectionType)
{
throw new EmptyEnvelopeException(
"Current OVF description document includes a VirtualSystemCollection, "
+ "abicloud only deal with single virtual system based OVFs");
}
VirtualSystemType vsystem = (VirtualSystemType) content;