AuctionSniper.java

package auctionsniper;

import auctionsniper.UserRequestListener.Item;
import auctionsniper.util.Announcer;

public class AuctionSniper implements AuctionEventListener {
  private final Announcer<SniperListener> listeners = Announcer.to(SniperListener.class);
  private final Auction auction;
  private SniperSnapshot snapshot;
  private final Item item; 
    
  public AuctionSniper(Item item, Auction auction) {
    this.item = item;
    this.auction = auction;
    this.snapshot = SniperSnapshot.joining(item.identifier);
  }

  public void addSniperListener(SniperListener listener) {
    listeners.addListener(listener);
  }
  
  public void auctionClosed() {
    snapshot = snapshot.closed();
    notifyChange();
  }

  public void auctionFailed() {
    snapshot = snapshot.failed(); 
    notifyChange();
  }
  
  public void currentPrice(int price, int increment, PriceSource priceSource) {
    switch(priceSource) {
    case FromSniper:
      snapshot = snapshot.winning(price); 
      break;
    case FromOtherBidder:
      int bid = price + increment;
      if (item.allowsBid(bid)) {
        auction.bid(bid);
        snapshot = snapshot.bidding(price, bid);
      } else {
        snapshot = snapshot.losing(price);
      }
      break;
    }
    notifyChange();
  }

  public SniperSnapshot getSnapshot() {
    return snapshot;
  }
  
  private void notifyChange() {
    listeners.announce().sniperStateChanged(snapshot);
  }

}