1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
package javassist.tools;
import javassist.CannotCompileException;
import javassist.CtBehavior;
import java.util.HashMap;
import java.util.UUID;
/**
* Creates bytecode that when executed calls back to the instance's result method.
*
* Inserts callbacks in <code>CtBehaviour</code>
*
*/
public abstract class Callback {
public static HashMap<String, Callback> callbacks = new HashMap<String, Callback>();
private final String sourceCode;
/**
* Constructs a new <code>Callback</code> object.
*
* @param src The source code representing the inserted callback bytecode.
* Can be one or many single statements or blocks each returning one object.
* If many single statements or blocks are used they must be comma separated.
*/
public Callback(String src){
String uuid = UUID.randomUUID().toString();
callbacks.put(uuid, this);
sourceCode = "((javassist.tools.Callback) javassist.tools.Callback.callbacks.get(\""+uuid+"\")).result(new Object[]{"+src+"});";
}
/**
* Gets called when bytecode is executed
*
* @param objects Objects that the bytecode in callback returns
*/
public abstract void result(Object... objects);
@Override
public String toString(){
return sourceCode();
}
public String sourceCode(){
return sourceCode;
}
/**
* Inserts callback at the beginning of the body.
*
* @param callback The callback
*
* @see CtBehavior#insertBefore(String)
*/
public static void insertBefore(CtBehavior behavior, Callback callback)
throws CannotCompileException
{
behavior.insertBefore(callback.toString());
}
/**
* Inserts callback at the end of the body.
* The callback is inserted just before every return instruction.
* It is not executed when an exception is thrown.
*
* @param behavior The behaviour to insert callback in
* @param callback The callback
*
* @see CtBehavior#insertAfter(String, boolean)
*/
public static void insertAfter(CtBehavior behavior,Callback callback)
throws CannotCompileException
{
behavior.insertAfter(callback.toString(), false);
}
/**
* Inserts callback at the end of the body.
* The callback is inserted just before every return instruction.
* It is not executed when an exception is thrown.
*
* @param behavior The behaviour to insert callback in
* @param callback The callback representing the inserted.
* @param asFinally True if the inserted is executed
* Not only when the control normally returns
* but also when an exception is thrown.
* If this parameter is true, the inserted code cannot
* access local variables.
*
* @see CtBehavior#insertAfter(String, boolean)
*/
public static void insertAfter(CtBehavior behavior, Callback callback, boolean asFinally)
throws CannotCompileException
{
behavior.insertAfter(callback.toString(), asFinally);
}
/**
* Inserts callback at the specified line in the body.
*
* @param behavior The behaviour to insert callback in
* @param callback The callback representing.
* @param lineNum The line number. The callback is inserted at the
* beginning of the code at the line specified by this
* line number.
*
* @return The line number at which the callback has been inserted.
*
* @see CtBehavior#insertAt(int, String)
*/
public static int insertAt(CtBehavior behavior, Callback callback, int lineNum)
throws CannotCompileException
{
return behavior.insertAt(lineNum, callback.toString());
}
}
|
