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1 package samples.tracing;
2
3 import net.sf.cglib.proxy.MethodProxy;
4 import net.sf.cglib.proxy.MethodInterceptor;
5 import net.sf.cglib.proxy.Enhancer;
6
7
10 public class Trace implements MethodInterceptor {
11
12 public static class Target {
13 static int s_count = 0;
14
15 private int m_count;
16
17 public Target() {
18 m_count = s_count++;
19 }
20
21 public void step1() {
22 step2(new Target());
23 }
24
25 public void step2(Target arg) {
26 step3();
27 }
28
29 public void step3() {
30 }
31
32 public String  toString() {
33 return "I am Target " + m_count;
34 }
35 }
36
37 int ident = 1;
38 static Trace callback = new Trace();
39
40 public static Object newInstance(Class clazz) {
41 try {
42 Enhancer e = new Enhancer();
43 e.setSuperclass(clazz);
44 e.setCallback(callback);
45 return e.create();
46 } catch (Throwable e) {
47 e.printStackTrace();
48 throw new Error (e.getMessage());
49 }
50
51 }
52
53 public static void main(String [] args) {
54 Target target = (Target) newInstance(Target.class);
55 target.step1();
56 }
57
58
59 public Object intercept(Object obj, java.lang.reflect.Method method, Object [] args, MethodProxy proxy)
60 throws Throwable {
61 printIdent(ident);
62 System.out.println(method);
63 for (int i = 0; i < args.length; i++) {
64 printIdent(ident);
65 System.out.print("arg" + (i + 1) + ": ");
66 if (obj == args[i]) {
67 System.out.println("this");
68 } else {
69 System.out.println(args[i]);
70 }
71 }
72 ident++;
73
74 Object retValFromSuper = null;
75 try {
76 retValFromSuper = proxy.invokeSuper(obj, args);
77 ident--;
78 } catch (Throwable t) {
79 ident--;
80 printIdent(ident);
81 System.out.println("throw " + t);
82 System.out.println();
83 throw t.fillInStackTrace();
84 }
85
86 printIdent(ident);
87 System.out.print("return ");
88 if (obj == retValFromSuper) {
89 System.out.println("this");
90 } else {
91 System.out.println(retValFromSuper);
92 }
93
94 if (ident == 1) {
95 System.out.println();
96 }
97
98 return retValFromSuper;
99 }
100
101 void printIdent(int ident) {
102 while (--ident > 0) {
103 System.out.print(".......");
104 }
105 System.out.print(" ");
106 }
107
108 private Trace() {
109 }
110 } |
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