Question

1. Modify the Auction class according to these exercises:
   • 4.48: close method
   • 4.49: getUnsold method
   • 4.51: Rewrite getLot method
   • 4.52: removeLot method
2. For help watch Textbook Video Note 4.2 which shows you how to use and test the auction project, as well as solving the getUnsold exercise.
3. Document with javadoc and use good style (Appendix J) as usual.
4. Test your code thoroughly as you go.
5. Create a jar file of your project.
   1. From BlueJ, choose Project->Create Jar File...
   2. Check the "Include source" check box

import java.util.ArrayList;

/**
* A simple model of an auction.
* The auction maintains a list of lots of arbitrary length.
*
* @author David J. Barnes and Michael Kölling.
* @version 2011.07.31
*/
public class Auction
{
// The list of Lots in this auction.
private ArrayList<Lot> lots;
// The number that will be given to the next lot entered
// into this auction.
private int nextLotNumber;

/**
* Create a new auction.
*/
public Auction()
{
lots = new ArrayList<Lot>();
nextLotNumber = 1;
}

/**
* Enter a new lot into the auction.
* @param description A description of the lot.
*/
public void enterLot(String description)
{
lots.add(new Lot(nextLotNumber, description));
nextLotNumber++;
}

/**
* Show the full list of lots in this auction.
*/
public void showLots()
{
for(Lot lot : lots) {
System.out.println(lot.toString());
}
}
  
/**
* Make a bid for a lot.
* A message is printed indicating whether the bid is
* successful or not.
*
* @param lotNumber The lot being bid for.
* @param bidder The person bidding for the lot.
* @param value The value of the bid.
*/
public void makeABid(int lotNumber, Person bidder, long value)
{
Lot selectedLot = getLot(lotNumber);
if(selectedLot != null) {
Bid bid = new Bid(bidder, value);
boolean successful = selectedLot.bidFor(bid);
if(successful) {
System.out.println("The bid for lot number " +
lotNumber + " was successful.");
}
else {
// Report which bid is higher.
Bid highestBid = selectedLot.getHighestBid();
System.out.println("Lot number: " + lotNumber +
" already has a bid of: " +
highestBid.getValue());
}
}
}

/**
* Return the lot with the given number. Return null
* if a lot with this number does not exist.
* @param lotNumber The number of the lot to return.
*/
public Lot getLot(int lotNumber)
{
if((lotNumber >= 1) && (lotNumber < nextLotNumber)) {
// The number seems to be reasonable.
Lot selectedLot = lots.get(lotNumber - 1);
// Include a confidence check to be sure we have the
// right lot.
if(selectedLot.getNumber() != lotNumber) {
System.out.println("Internal error: Lot number " +
selectedLot.getNumber() +
" was returned instead of " +
lotNumber);
// Don't return an invalid lot.
selectedLot = null;
}
return selectedLot;
}
else {
System.out.println("Lot number: " + lotNumber +
" does not exist.");
return null;
}
}
}

Lot coding is

/**

* A class to model an item (or set of items) in an
* auction: a lot.
*
* @author David J. Barnes and Michael Kölling.
* @version 2011.07.31
*/
public class Lot
{
// A unique identifying number.
private final int number;
// A description of the lot.
private String description;
// The current highest bid for this lot.
private Bid highestBid;

/**
* Construct a Lot, setting its number and description.
* @param number The lot number.
* @param description A description of this lot.
*/
public Lot(int number, String description)
{
this.number = number;
this.description = description;
this.highestBid = null;
}

/**
* Attempt to bid for this lot. A successful bid
* must have a value higher than any existing bid.
* @param bid A new bid.
* @return true if successful, false otherwise
*/
public boolean bidFor(Bid bid)
{
if(highestBid == null) {
// There is no previous bid.
highestBid = bid;
return true;
}
else if(bid.getValue() > highestBid.getValue()) {
// The bid is better than the previous one.
highestBid = bid;
return true;
}
else {
// The bid is not better.
return false;
}
}
  
/**
* @return A string representation of this lot's details.
*/
public String toString()
{
String details = number + ": " + description;
if(highestBid != null) {
details += " Bid: " +
highestBid.getValue();
}
else {
details += " (No bid)";
}
return details;
}

/**
* @return The lot's number.
*/
public int getNumber()
{
return number;
}

/**
* @return The lot's description.
*/
public String getDescription()
{
return description;
}

/**
* @return The highest bid for this lot.
* This could be null if there is
* no current bid.
*/
public Bid getHighestBid()
{
return highestBid;
}
}

Answer 1

Please let me know if you have any doubts or you want me to modify the answer. And if you find this answer useful then don't forget to rate my answer as thumps up. Thank you! :)

import java.util.ArrayList;
import java.util.Iterator;

public class Auction
{
    private ArrayList<Lot> lots;
    private int nextLotNumber;
    private Auction auction1;
    private Lot chindo;
    private Lot keyfi;
    private Lot taco;

    public Auction()
    {
        lots = new ArrayList<>();
        nextLotNumber = 1;
    }

    public void createScenario()
    {
        int n = 1;
        Person jack = new Person("John");
        Person jill = new Person("Bob");

        Lot abc = new Lot((n++), "Used Abc");
        Lot def = new Lot((n++), "Def");
        Lot ghijklm = new Lot((n++), "Ghi Jklm");

        auction1.enterLot("abc");
        auction1.enterLot("def");
        auction1.enterLot("ghijklm");

        auction1.makeABid(1, jack, 569);
        auction1.makeABid(3, jill, 4545);

        close();

    }

    public ArrayList<Lot> getUnsold()
    {
        ArrayList<Lot> unsold = new ArrayList<Lot>();
        for(Lot lot: lots){
            Bid bid = lot.getHighestBid();

            if(bid == null){
                unsold.add(lot);
            }
        }
        return unsold;
    }

   public void close()
    {
        ArrayList noBid = new ArrayList<Lot>();
        System.out.println("The results of the auction are as follows:");

        System.out.println("-----------------------------------------------------");
        for(Lot lot : lots){
            Bid bid = lot.getHighestBid();
            if(bid != null){
                System.out.println("Item Number: " + lot.getNumber());
                System.out.println("Item Description: " + lot.getDescription());
                System.out.println("We have a winner!");
                System.out.println("Bidder: " + bid.getBidder());
                System.out.println("-----------------------------------------------------");
            }
        }
        System.out.println("The following items received no bids:");
        System.out.println(getUnsold());
    }

  

    public void enterLot(String description)
    {
        lots.add(new Lot(nextLotNumber, description));
        nextLotNumber++;
    }

    public void showLots()
    {
        for(Lot lot : lots) {
            System.out.println(lot.toString());
        }
    }

    public void makeABid(int lotNumber, Person bidder, long value)
    {
        Lot selectedLot = getLot(lotNumber);
        if(selectedLot != null) {
            boolean successful = selectedLot.bidFor(new Bid(bidder,value));
            if(successful) {
                System.out.println("The bid for lot number " +
                        lotNumber + " was successful.");
            }
            else {
                Bid highestBid = selectedLot.getHighestBid();
                System.out.println("Lot number: " + lotNumber +
                        " already has a bid of: " +
                        highestBid.getValue());
            }
        }
    }

  
    public Lot removeLot(int lotToRemove)
    {
        int index = 0;
        int rmvLot = lotToRemove;
        boolean found = false;

        if(lotToRemove >= lots.size()){
            return null;
        }
        else{
            while(index <= lots.size() && index <= (lotToRemove - 1) && found == false){
                Lot lot = lots.get(index);

                if((lots.get(index) == lots.get(rmvLot -1))){
                    found = true;
                }
                else{
                    index += 1;
                }
            }
        }
        return lots.get(index);
    }

    public Lot getLot(int lotNumber)
    {
        if((lotNumber >= 1) && (lotNumber < nextLotNumber)) {
            return lots.get((lotNumber-1));
        }
        else {
            System.out.println("Lot number: " + lotNumber +
                    " does not exist.");
            return null;
        }
    }
}
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
public class Lot
{
    private final int number;
    private String description;
    private Bid highestBid;

    public Lot(int number, String description)
    {
        this.number = number;
        this.description = description;
        this.highestBid = null;
    }

    public boolean bidFor(Bid bid)
    {
        if(highestBid == null) {
            highestBid = bid;
            return true;
        }
        else if(bid.getValue() > highestBid.getValue()) {
            highestBid = bid;
            return true;
        }
        else {

            return false;
        }
    }

    public String toString()
    {
        String details = number + ": " + description;
        if(highestBid != null) {
            details += "    Bid: " +
                    highestBid.getValue();
        }
        else {
            details += "    (No bid)";
        }
        return details;
    }

    public int getNumber()
    {
        return number;
    }

    public String getDescription()
    {
        return description;
    }

    public Bid getHighestBid()
    {
        return highestBid;
    }
}

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
public class Bid
{
    private final Person bidder;
    private final long value;

    public Bid(Person bidder, long value)
    {
        this.bidder = bidder;
        this.value = value;
    }

    public Person getBidder()
    {
        return bidder;
    }

    public long getValue()
    {
        return value;
    }
}
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
public class Person
{
    private final String name;

    public Person(String name)
    {
        this.name = name;
    }

    public String getName()
    {
        return name;
    }
}

Auction [-/ldeaProjects Auction] - .src/Auction.java [Auction] Auction-src Auction e IAuction javaLot java Bid java XPerson,java Project import java.util.ArrayList import Java.util.Iterator ▼『Auction idea public class Auction Auction private ArrayListcLot> lots private int nextlotNumber; private Auction auctionl: private Lot chindo: private Lot keyfi private Lot taco: Bid Lot Person Auction.iml lth External Libraries b Scratches and Consoles public AuctionC) lots new ArrayListo) 15 public void createscenario) 20 int n 1; Person jack = new Person( name: "John"); Person jill- new Person name: "Bob) 23 Lot abc-new Lot((n++), description "Used Abc"); Lot def new Lot((n), description Lot ghijkimnew Lot((n), descriptions "Ghi Jk3m) 25 "Def): 26 28 auction1.enterLot( description: "abc); auction1.enterLot description: "def) auctionl.enterLot description: "gbddklm") 29 32 auction1.makeABid lotNumber: 1, jack, value: 569) auctionl.makeABid lotNumber: 3,jill, value: 4545) 35 close); 36 38 public ArrayListcLot> getUnsold() 41 ArrayList<cLot> unsold-new ArrayList<lot>) for(Lot Lot: Lots) Bid bidlot.getHighestBid); if(bid-nullf unsold.add( Lot) 521 LF: UTF-8: a