void verifyUniqueXids(List<OFMessage> msgs){
  if (seenXids == null)   seenXids=new HashSet<Integer>();
  for (  OFMessage m : msgs) {
    int xid=m.getXid();
    assertTrue("Xid in messags is 0",xid != 0);
    assertFalse("Xid " + xid + " has already been used",seenXids.contains(xid));
    seenXids.add(xid);
  }
}

void verifyUniqueXids ( List < OFMessage > msgs ) { if ( seenXids == null ) seenXids = new HashSet < Integer > ( ) ; for ( OFMessage m : msgs ) { int xid = m . getXid ( ) ; assertTrue ( "Xid in messags is 0" , xid != 0 ) ; assertFalse ( "Xid " + xid + " has already been used" , seenXids . contains ( xid ) ) ; seenXids . add ( xid ) ; } }
make sure that the transaction ids in the given messages are not 0 and differ between each other . while it ' s not a defect per se if the xids are we want to ensure we use different ones for each message we send .
