title: Creating constructor for an Auction that makes an object containing an ArrayList of previously unsold Lots
body: <p>Not sure if my title is worded okay, but
  I'm using BlueJ to learn a bit of Java, and I'm working on an Auction project (based off an example in chapter 4 of <em>Objects First With Java: A Practical Introduction Using BlueJ</em>, with some changes). What I'm trying to do is add a second constructor that takes an Auction as parameter, and if that Auction is currently closed, creates a new Auction with the unsold lots from it. If it it's still open or null, this constructor should work like my default constructor.</p>
  
  <p>Here's the start of my code with my default constructor:</p>
  
  <pre><code>...
  
  public class Auction
  {
      // The list of Lots in this auction.
      private ArrayList&lt;Lot&gt; lots;
      // The number that will be given to the next lot entered
      // into this auction.
      private int nextLotNumber;
      // Whether or not the auction is open for bidding.
      private boolean openForBid;
  
      /**
       * Create a new auction.
       */
      public Auction()
      {
          lots = new ArrayList&lt;Lot&gt;();
          nextLotNumber = 1;
          openForBid = true;
      }
  
      /**
       * Second Constructor
       */ 
      public Auction(Auction auction)
      {
          //If the auction is open..
              //Create a new Auction the same as above
          //else..
              //create a new auction with unsold lots from the specified auction
      }
  </code></pre>
  
  <p>I am working off of a skeleton for this Auction class with little instruction, but there is a method that should return an ArrayList of the lots which currently have no bids.</p>
  
  <pre><code>public ArrayList&lt;Lot&gt; getNoBids()
  </code></pre>
  
  <p>So I figure I need to call that on the Auction passed to the constructor, but I can't seem to wrap my head around putting this all together. Any help is appreciated as I am fairly new to Java and ArrayLists! Thanks.</p>