1   // Example 5.2 joi/examples/OverridingDemo.java                         
2   //                                                            
3   //                                                            
4   // Copyright 2003 Bill Campbell and Ethan Bolker                         
5                                                               
6   // Small program to illustrate overriding and toString()
7   // 
8   // Here's what the output looks like:
9   //
10  // %> java Overriding jessica benjamin
11  // Terminal t = new Terminal();
12  // nobj = new NamedObject( args[0] );
13  // nobj.toString():           jessica
14  // nobj:                      jessica
15  // nobj.toStringfromObject(): NamedObject@206fdf64
16  // nobj = new NamedObject( args[1] );
17  // nobj.toString():           benjamin
18  // nobj:                      benjamin
19  // nobj.toStringfromObject(): NamedObject@2103df64 
20  // 
21  // toString():                Terminal@201bdf64
22  // t:                         Terminal@201bdf64
23  
24  public class OverridingDemo
25  {
26      public static void main( String[] args )   
27      {
28          Terminal t = new Terminal();
29          NamedObject nobj;
30  
31          t.println("Terminal t = new Terminal();");
32          t.println("nobj = new NamedObject( args[0] );");
33          nobj = new NamedObject( args[0] );
34          t.println( "nobj.toString():           " + nobj.toString() );
35          t.println( "nobj:                      " + nobj );
36          t.println( "nobj.toStringfromObject(): " + 
37                     nobj.toStringfromObject());
38  
39          t.println("nobj = new NamedObject( args[1] );");
40          nobj = new NamedObject( args[1] );
41          t.println( "nobj.toString():           " + nobj.toString() );
42          t.println( "nobj:                      " + nobj );
43          t.println( "nobj.toStringfromObject(): " + 
44                     nobj.toStringfromObject());
45  
46          t.println( "\ntoString():                " + t.toString() );
47          t.println( "t:                         " + t );
48      } 
49  }
50  
51  // A simple class whose instances have one field 
52  // and several toString methods. Visible only inside
53  // the OverridingDemo class.
54  
55  // you can put two classes in one file as long as only one of them
56  // is public
57  
58  class NamedObject // extends Object, by default 
59  {  
60      private String name;
61          
62      // constructor does the obvious thing
63  
64      public NamedObject( String name ) 
65      {
66          this.name = name;
67      }
68  
69      // override toString in class Object     
70  
71      public String toString()
72      {
73          return name;
74      }
75          
76      // access to the overridden method using super
77  
78      public String toStringfromObject() 
79      {
80          return super.toString();
81      }
82  }
83