cardhand.java

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/* CardHand.java - an example to show the differences among
 * reference copy, shallow copy, and deep copy.
 * Copyright (c) 2001, Bruce E. Wampler
 */
public class CardHand implements Cloneable
{
    private Card c1;            // A CardHand has 2 cards
    private Card c2;
    
    public CardHand(Card cd1, Card cd2)
    {
        c1 = cd1; c2 = cd2;
    }
    
    public String toString()
    {
        return "c1:" + c1 + ","+" c2:" + c2;
    }

// **** UNCOMMENT the clone method for SHALLOW and DEEP COPY
//      // override Object.clone()
//      public Object clone() throws CloneNotSupportedException
//      {
//          // To clone, first shallow clone whole object.
//          CardHand c = (CardHand) super.clone();
// // **** UNCOMMENT next THREE line for DEEP COPY ONLY
// //         // now clone the deep parts
// //         c.c1 = (Card) c1.clone();
// //         c.c2 = (Card) c2.clone();
//          return c;
//      }
    
    static void main(String args[])
                throws CloneNotSupportedException
    {
        Card newCard = new Card(Card.HEART,7);
        CardHand origHand =
           new CardHand(new Card(Card.SPADE, 1),
                        new Card(Card.SPADE, 13));

// **** UNCOMMENT next 3 lines for copy by reference ****
        CardHand saveHand = origHand;
        System.out.println("\n**** REFERENCE COPY ****\n\n"
                + "BEFORE: saveHand = origHand; :\n"

// **** UNCOMMENT next 3 lines for SHALLOW COPY ****
//        CardHand saveHand = (CardHand) origHand.clone();
//        System.out.println("\n**** SHALLOW COPY ****\n\n"
//                + "BEFORE: saveHand = origHand.clone(); :\n"

// **** UNCOMMENT next 3 lines for DEEP COPY version ****
//        CardHand saveHand = (CardHand) origHand.clone();
//        System.out.println("\n**** DEEP COPY ****\n\n"
//                + "BEFORE: saveHand = origHand.clone(); :\n"

                + "\n           origHand is " + origHand
                + "\n           saveHand is " + saveHand
                + "\n           newCard  is " + newCard + "\n");
                
        origHand.c1 = newCard;
        origHand.c2.setCard(Card.DIAMOND,4);
        newCard.setCard(Card.CLUB, 2);

        System.out.println(
                  "AFTER: origHand.c1 = newCard;\n"
                + "       origHand.c2.setCard(DIAMOND,4);\n"
                + "       newCard.setCard(CLUB,2); :\n"
                + "\n           origHand is " + origHand
                + "\n           saveHand is " + saveHand
                + "\n           newCard  is " + newCard + "\n");
    }
}