updated to generic

uebung07/src/oop/ch05/mensa/AccountCard.java

@@ -5,15 +5,15 @@ import oop.ch05.secured.SecuredContent;
 import oop.ch05.secured.SecurityClient;
 
 public class AccountCard extends MensaCard {
-  private final SecuredContent account;
+  private final SecuredContent<String> account;
 
   public AccountCard(String key, String account, int password) {
     super(key, Color.white);
-    this.account = new SecuredContent(password, account);
+    this.account = new SecuredContent<>(password, account);
   }
 
   public String getAccount() {
-    return (String) account.getContent();
+    return account.getContent();
   }
 
   public void setAccount(SecurityClient client, String account) throws AuthorizationException {

uebung07/src/oop/ch05/mensa/CashCard.java

@@ -4,17 +4,17 @@ import oop.ch05.secured.AuthorizationException;
 import oop.ch05.secured.SecuredContent;
 
 public class CashCard extends MensaCard {
-  private final SecuredContent balance;
+  private final SecuredContent<Integer> balance;
 
   public CashCard(String key, Color color, int password) {
     super(key, color);
-    balance = new SecuredContent(password, 0);
+    balance = new SecuredContent<>(password, 0);
     if (color != Color.blue && color != Color.green)
       throw new IllegalArgumentException("Invalid CashCard color " + color);
   }
 
   public int getBalance() {
-    return (Integer) balance.getContent();
+    return balance.getContent();
   }
 
   void deposit(VendingMachine client, int cents)

uebung07/src/oop/ch05/secured/SecuredContent.java

@@ -7,13 +7,14 @@ import java.util.Random;
  * by a challenge-response approach. The content may be read at any time, but
  * only authorized clients are allowed to modify the contents.
  *
+ * @param <E> the type of the actual secured content
  * @author Mark Minas
  */
-public class SecuredContent {
+public class SecuredContent<E> {
   /**
    * The actual, secured content
    */
-  private Object content;
+  private E content;
   /**
    * A random number generator used for generating challenges.
    */
@@ -30,7 +31,7 @@ public class SecuredContent {
    *                 challenge.
    * @param content  the contained content
    */
-  public SecuredContent(int password, Object content) {
+  public SecuredContent(int password, E content) {
     this.password = password;
     this.content = content;
   }
@@ -39,7 +40,7 @@ public class SecuredContent {
    * Returns the contained contents. There is no authorization necessary for
    * reading the contents.
    */
-  public Object getContent() {
+  public E getContent() {
     return content;
   }
 
@@ -52,12 +53,12 @@ public class SecuredContent {
    * @param content The new contained contents
    * @throws AuthorizationException if the specified client cannot authorize himself
    */
-  public void setContent(SecurityClient client, Object content)
+  public void setContent(SecurityClient client, E content)
       throws AuthorizationException {
     final int challenge = nextChallenge();
     if (client.challengeResponse(challenge) != requiredResponse(challenge))
       throw new AuthorizationException(client
-                                       + " is not authorized to access contents.");
+                                           + " is not authorized to access contents.");
     this.content = content;
   }