Auction

1. Class Window

2. Instances

3. Source Code

import java.util.ArrayList;
/**
 * Auction Class.
 *
 * @author (Arino Jenynof)
 * @version (20181008)
 */
public class Auction
{
    private ArrayList<Lot> lots;
    private int nextLotNumber;
    
    public Auction()
    {
        lots = new ArrayList<Lot>();
        nextLotNumber = 1;
    }
    
    public void enterLot(String desc)
    {
        lots.add(new Lot(nextLotNumber, desc));
        nextLotNumber++;
    }
    
    public void showLot()
    {
        for (Lot lot : lots)
        {
            System.out.println(lot.toString());
        }
    }
    
    public void makeABid(int lotNum, Person bidder, long value)
    {
        Lot selectedLot = getLot(lotNum);
        if (selectedLot != null)
        {
            Bid bid = new Bid(bidder, value);
            boolean success = selectedLot.bidFor(bid);
            if (success)
            {
                System.out.println(bidder.getName() + "'s bid for lot number " + lotNum + " was successful");
            }
            else
            {
                Bid highestBid = selectedLot.getHighestBid();
                System.out.println("Lot number: " + lotNum + " already has a bid of " + highestBid.getValue() + ", " + bidder.getName() + "'s bid unsuccessful");
            }
        }
    }
    
    public Lot getLot(int lotNum)
    {
        if (lotNum >= 1 && lotNum < nextLotNumber)
        {
            Lot selectedLot = lots.get(lotNum - 1);
            if (selectedLot.getNumber() != lotNum)
            {
                System.out.println("Internal Error: Lot number " + selectedLot.getNumber() + " was returned instead of " + lotNum);
                selectedLot = null;
            }
            return selectedLot;
        }
        else
        {
            System.out.println("Lot number: " + lotNum + " doesn't exist");
            return null;
        }
    }
    
    public void stop()
    {
        System.out.println("Auction is finished!");
        for (Lot lot : lots)
        {
            if (lot.getHighestBid() != null)
            {
                System.out.println("Lot number: " + lot.getNumber() + " sold with price of " + lot.getHighestBid().getValue() + " to " + lot.getHighestBid().getBidder().getName());
            }
            else
            {
                System.out.println("Lot number: " + lot.getNumber() + " didn't sell");
            }
        }
    }
}

/**
 * Lot Class;
 *
 * @author (Arino Jenynof)
 * @version (20181008)
 */
public class Lot
{
    private int lotNumber;
    private Bid highestBid;
    private String desc;
    
    public Lot(int lotNumber, String desc)
    {
        highestBid = null;
        this.lotNumber = lotNumber;
        this.desc = desc;
    }
    
    public boolean bidFor(Bid bid)
    {
        if (highestBid == null)
        {
            highestBid = bid;
            return true;
        }
        else if (highestBid.getValue() < bid.getValue())
        {
            highestBid = bid;
            return true;
        }
        else
        {
            return false;
        }
    }
    
    public Bid getHighestBid()
    {
        return highestBid;
    }
    
    public int getNumber()
    {
        return lotNumber;
    }
    
    public String toString()
    {
        return "Lot number: " + lotNumber + " is " + desc;
    }
}

/**
 * Bid Class.
 *
 * @author (Arino Jenynof)
 * @version (20181008)
 */
public class Bid
{
    private long value;
    private Person bidder;
    
    public Bid(Person bidder, long value)
    {
        this.bidder = bidder;
        this.value = value;
    }
    
    public long getValue()
    {
        return value;
    }
    
    public Person getBidder()
    {
        return bidder;
    }
}

/**
 * Person Class.
 *
 * @author (Arino Jenynof)
 * @version (20101008)
 */
public class Person
{
    private String name;
    
    public Person(String name)
    {
        this.name = name;
    }
    
    public String getName()
    {
        return name;
    }
}

4. Output

Setelah memasukkan lot melalui method enterLot(), menjalankan method showLot() akan menunjukkan semua lot yang sudah dimasukkan

Menggunakan method makeABid() untuk melakukan pelelangan

stop() method untuk menghentikan pelelangan