Create tutorial_52.java

Author: simply-coded

code/tutorial_52.java

@@ -0,0 +1,99 @@
+//
+//
+public class Driver {
+    
+    public static void main(String[] args) {        
+        String[] friends = {"jim","kate","bill","mark","devin","alice","melvin","jeremy","bob"};                  
+        String space = " ";
+        
+        // example 1 - normal show method
+        Messenger messager1 = new MyMessenger(friends);
+        messager1.show();
+
+        // example 2 - create a class to override the show method
+        Messenger messager2 = new BetterMessenger(friends);
+        messager2.show();
+
+        // example 3 - create an anonymous class to override the show method
+        Messenger messager3 = new MyMessenger(friends) {
+            public void show() {
+                for (String name : contactList) {
+                    System.out.print(name + " ");
+                }
+                System.out.println();
+            }
+        };
+        messager3.show();
+
+        // example 4 - create an anonymous class to implement the entire interface
+        final String sp = space;
+        final String[] names = friends;
+        Messenger messager = new Messenger() {              
+
+            public void send(String message) {
+                for (String name : names) {
+                    System.out.println(name + ": " + message);
+                }
+            }
+
+            public void show() {
+                for (String name : names) {
+                    System.out.print(name + sp);
+                }
+                System.out.println();
+            }
+        };
+        messager.show();    
+        
+        // changing space variable now works because we created the sp variable.
+        space = "  ";        
+    }
+
+}
+//
+//
+class MyMessenger implements Messenger {
+
+    protected String[] contactList;
+
+    public MyMessenger(String[] names) {
+        contactList = names;
+    }
+ 
+    public void send(String message) {
+        for (String name : contactList) {
+            System.out.println(name + ": " + message);
+        }
+    }
+
+    public void show() {
+        for (String name : contactList) {
+            System.out.println(name);
+        }
+    }
+
+}
+//
+//
+class BetterMessenger extends MyMessenger {
+
+    public BetterMessenger (String[] names) {
+        super(names);
+    }
+
+    @Override
+    public void show() {
+        for (String name : contactList) {
+            System.out.print(name + " ");
+        }
+        System.out.println();
+    }
+}
+//
+//
+interface Messenger {
+
+    void send(String message);
+    void show();    
+
+}