@Override
 public void calledOperationFailed(Operation op) {
   if (op instanceof BTOperationDownload) {
     logger.process(
         this.getClass().toString(),
         new Object[] {op, new Long(Simulator.getCurrentTime()), new Boolean(false)});
   }
 }
 @Override
 public void calledOperationSucceeded(Operation opd) {
   if (opd instanceof BTOperationDownload) {
     BTOperationDownload op = (BTOperationDownload) opd;
     logger.process(
         this.getClass().toString(),
         new Object[] {op, new Long(op.getFinishedTime()), new Boolean(true)});
   }
 }