01: /*
02: * Copyright 2002-2007 the original author or authors.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16:
17: package org.springframework.instrument;
18:
19: import java.lang.instrument.Instrumentation;
20:
21: /**
22: * Java agent that saves the {@link Instrumentation} interface from the JVM for
23: * later use.
24: *
25: * @author Rod Johnson
26: * @since 2.0
27: * @see org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver
28: */
29: public class InstrumentationSavingAgent {
30:
31: private static volatile Instrumentation instrumentation;
32:
33: /**
34: * Save the {@link Instrumentation} interface exposed by the JVM.
35: */
36: public static void premain(String agentArgs, Instrumentation inst) {
37: instrumentation = inst;
38: }
39:
40: /**
41: * Return the {@link Instrumentation} interface exposed by the JVM.
42: * @return the <code>Instrumentation</code> instance previously saved when
43: * the {@link #premain} method was called by the JVM; will be <code>null</code>
44: * if this class was not used as Java agent when this JVM was started.
45: */
46: public static Instrumentation getInstrumentation() {
47: return instrumentation;
48: }
49:
50: }
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