1    /* 
2      A base-level class controlled by VerboseMetaobj. 
3    */ 
4     
5    package javassist.sample.reflect; 
6     
7    import javassist.reflect.Metalevel; 
8    import javassist.reflect.Metaobject; 
9     
10   public class Person { 
11       public String name; 
12       public static int birth = 3; 
13       public static final String defaultName = "John"; 
14    
15       public Person(String name, int birthYear) { 
16           if (name == null) 
17               this.name = defaultName; 
18           else 
19               this.name = name; 
20    
21           this.birth = birthYear; 
22       } 
23    
24       public String getName() { 
25           return name; 
26       } 
27    
28       public int getAge(int year) { 
29           return year - birth; 
30       } 
31    
32       public static void main(String[] args) { 
33           String name; 
34           if (args.length > 0) 
35               name = args[0]; 
36           else 
37               name = "Bill"; 
38    
39           Person p = new Person(name, 1960); 
40           System.out.println("name: " + p.getName()); 
41           System.out.println("object: " + p.toString()); 
42    
43           // change the metaobject of p. 
44           if (p instanceof Metalevel) { 
45               ((Metalevel) p)._setMetaobject(new Metaobject(p, null)); 
46               System.out.println("<< the metaobject was changed.>>"); 
47           } 
48    
49           System.out.println("age: " + p.getAge(1999)); 
50       } 
51   } 
52