Lab10 Hints and Tips

Part 1

• In step 4a-c on page 10-3, your code might look like:

  PurchaseLog pl = new PurchaseLog();
  
  GasPurchase p = new GasPurchase ( 12.12, "1/1/2001" );
  pl.addPurchase ( p );
  
  p = new GasPurchase ( 20.01, "2/1/2001" );
  pl.addPurchase ( p );
  
  System.out.println ( "Total: " + pl.getTotalAmount() );
  	      

• In Step 4d on page 10-3, your code might look like (exception handling omitted):

  ObjectOutputStream oos =
      new ObjectOutputStream (
          new FileOutputStream ( xxxxxx ) );
  oos.writeObject ( xxxxx );
  oos.close();	      
  	      

• In Step 6a-c on page 10-3, your code might look like (exception handling omitted):

  PurchaseLog pl = null;
  
  ObjectInputStream ois =
      new ObjectInputStream (
          new FileInputStream ( xxxxxx ) );
  pl = (PurchaseLog)ois.readObject ();
  ois.close();
  
  System.out.println ( "Purchases: " + pl );
  System.out.println ( "Total: " + pl.getTotalAmount() );	      
  	      

Part 2

• In Step 2b on page 10-5, your code might look like (exception handling omitted):

  XMLEncoder e =
  	new XMLEncoder(
  		new BufferedOutputStream(new FileOutputStream(xxxxx)));
  
  e.writeObject(xxxxxx);
  e.close();
  	      

• In Step 5 on page 10-5, the code to reconstitute the object might look like (exception handling omitted):

  XMLDecoder d =
  	new XMLDecoder(
  		new BufferedInputStream(new FileInputStream(xxxxxx)));
  
  PurchaseLog pl = (PurchaseLog)d.readObject();
  System.out.println(pl.getTotalAmount());
  System.out.println(pl);
  d.close();