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
|
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tomcat;
import java.lang.instrument.ClassFileTransformer;
/**
* Specifies a class loader capable of being decorated with
* {@link ClassFileTransformer}s. These transformers can instrument
* (or weave) the byte code of classes loaded through this class loader
* to alter their behavior. Currently only
* {@link org.apache.catalina.loader.WebappClassLoaderBase} implements this
* interface. This allows web application frameworks or JPA providers
* bundled with a web application to instrument web application classes
* as necessary.
* <p>
* You should always program against the methods of this interface
* (whether using reflection or otherwise). The methods in
* {@code WebappClassLoaderBase} are protected by the default security
* manager if one is in use.
*
* @since 8.0, 7.0.64
*/
public interface InstrumentableClassLoader {
/**
* Adds the specified class file transformer to this class loader. The
* transformer will then be able to instrument the bytecode of any
* classes loaded by this class loader after the invocation of this
* method.
*
* @param transformer The transformer to add to the class loader
* @throws IllegalArgumentException if the {@literal transformer} is null.
*/
void addTransformer(ClassFileTransformer transformer);
/**
* Removes the specified class file transformer from this class loader.
* It will no longer be able to instrument the byte code of any classes
* loaded by the class loader after the invocation of this method.
* However, any classes already instrumented by this transformer before
* this method call will remain in their instrumented state.
*
* @param transformer The transformer to remove
*/
void removeTransformer(ClassFileTransformer transformer);
/**
* Returns a copy of this class loader without any class file
* transformers. This is a tool often used by Java Persistence API
* providers to inspect entity classes in the absence of any
* instrumentation, something that can't be guaranteed within the
* context of a {@link ClassFileTransformer}'s
* {@link ClassFileTransformer#transform(ClassLoader, String, Class,
* java.security.ProtectionDomain, byte[]) transform} method.
* <p>
* The returned class loader's resource cache will have been cleared
* so that classes already instrumented will not be retained or
* returned.
*
* @return the transformer-free copy of this class loader.
*/
ClassLoader copyWithoutTransformers();
}
|
