/*
* Copyright 2002-2010 the original author or authors.
*
* Licensed 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.springframework.instrument;
import java.lang.instrument.Instrumentation;
/**
* Java agent that saves the {@link Instrumentation} interface from the JVM
* for later use.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 2.0
* @see org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver
*/
public class InstrumentationSavingAgent {
private static volatile Instrumentation instrumentation;
/**
* Save the {@link Instrumentation} interface exposed by the JVM.
*/
public static void premain(String agentArgs, Instrumentation inst) {
instrumentation = inst;
}
/**
* Return the {@link Instrumentation} interface exposed by the JVM.
* <p>Note that this agent class will typically not be available in the classpath
* unless the agent is actually specified on JVM startup. If you intend to do
* conditional checking with respect to agent availability, consider using
* {@link org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver#getInstrumentation()}
* instead - which will work without the agent class in the classpath as well.
* @return the <code>Instrumentation</code> instance previously saved when
* the {@link #premain} method was called by the JVM; will be <code>null</code>
* if this class was not used as Java agent when this JVM was started.
* @see org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver#getInstrumentation()
*/
public static Instrumentation getInstrumentation() {
return instrumentation;
}
}
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