/**
  * Receives a new MarketTransaction. We look to see whether an order we have placed has cleared.
  */
 public synchronized void handleMessage(MarketTransaction tx) {
   // reset price escalation when a trade fully clears.
   Order lastTry = lastOrder.get(tx.getTimeslotIndex());
   if (lastTry == null) // should not happen
   log.error("order corresponding to market tx " + tx + " is null");
   else if (tx.getMWh() == lastTry.getMWh()) // fully cleared
   lastOrder.put(tx.getTimeslotIndex(), null);
 }