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1 package org.hansel;
2
3 import java.io.ByteArrayInputStream  ;
4 import java.io.FileOutputStream ;
5 import java.lang.instrument.ClassDefinition ;
6 import java.lang.instrument.ClassFileTransformer ;
7 import java.lang.instrument.IllegalClassFormatException ;
8 import java.lang.instrument.Instrumentation ;
9 import java.lang.instrument.UnmodifiableClassException ;
10 import java.security.ProtectionDomain ;
11 import java.util.List ;
12 import java.util.Set ;
13 import java.util.Vector ;
14
15 import org.objectweb.asm.ClassReader;
16 import org.objectweb.asm.ClassWriter;
17 import org.objectweb.asm.tree.ClassNode;
18
19 public class Transformer implements ClassFileTransformer {
20 private Set <String > classNames;
21 private List <ClassEntry> redefinedClasses = new Vector <ClassEntry>();
22
23 public Transformer(Set <String > classNames) {
24 this.classNames = classNames;
25 }
26
27 public byte[] transform(ClassLoader loader,
28 String className,
29 Class <?> classBeingRedefined,
30 ProtectionDomain protectionDomain,
31 byte[] classfileBuffer)
32 throws IllegalClassFormatException {
33
34 if (!classNames.contains(className.replace('/', '.'))) {
35 return null;
36 }
37
38 try {
39 ClassReader cr = new ClassReader(new ByteArrayInputStream (classfileBuffer));
40 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES + ClassWriter.COMPUTE_MAXS);
41
42 ClassNode cn = new ClassNode();
43 cr.accept(cn, 0);
44
45 TransformingAdapter ta = new TransformingAdapter(cw, cn, loader);
46
47 cn.accept(ta);
48
49 redefinedClasses.add(new ClassEntry(className, loader,
51 classfileBuffer));
52 byte[] result = cw.toByteArray();
53
54 if (cn.name.endsWith("Example")) {
55 FileOutputStream out = new FileOutputStream ("test.class");
56 out.write(result);
57 out.close();
58 }
59
61 return result;
62 } catch (Throwable e) {
63 e.printStackTrace();
64 throw new IllegalClassFormatException (e.getMessage());
65 }
66 }
67
68 public void undo(Instrumentation instrumentation)
69 throws ClassNotFoundException , UnmodifiableClassException {
70
71 ClassDefinition [] oldClasses =
72 new ClassDefinition [redefinedClasses.size()];
73
74 for (int i=0; i<oldClasses.length; i++) {
75 oldClasses[i] =
76 redefinedClasses.get(i).toClassDefinition();
77 }
78
79 instrumentation.redefineClasses(oldClasses);
80 }
81
82 private static class ClassEntry {
83 private ClassLoader cl;
84 private byte[] classBuffer;
85 private String classname;
86
87 public ClassEntry(String classname, ClassLoader cl,
88 byte[] classBuffer) {
89 this.cl = cl;
90 this.classname = classname;
91 this.classBuffer = classBuffer;
92
93
101 }
102
103 public ClassDefinition toClassDefinition() throws ClassNotFoundException {
104 return new ClassDefinition (cl.loadClass(classname.replace('/', '.')),
105 classBuffer);
106 }
107 }
108 }
109 |
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