/*
* Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.lang.instrument.*;
import java.net.*;
import java.util.*;
import java.io.*;
public class RedefineClassWithNativeMethodAgent {
static Class clz;
// just read the original class and redefine it via a Timer
public static void premain(String agentArgs, final Instrumentation inst) throws Exception {
String s = agentArgs.substring(0, agentArgs.indexOf(".class"));
clz = Class.forName(s.replace('/', '.'));
ClassLoader loader =
RedefineClassWithNativeMethodAgent.class.getClassLoader();
URL classURL = loader.getResource(agentArgs);
if (classURL == null) {
throw new Exception("Cannot find class: " + agentArgs);
}
int redefineLength;
InputStream redefineStream;
System.out.println("Reading test class from " + classURL);
if (classURL.getProtocol().equals("file")) {
File f = new File(classURL.getFile());
redefineStream = new FileInputStream(f);
redefineLength = (int) f.length();
} else {
URLConnection conn = classURL.openConnection();
redefineStream = conn.getInputStream();
redefineLength = conn.getContentLength();
}
final byte[] buffer = new byte[redefineLength];
new BufferedInputStream(redefineStream).read(buffer);
new Timer(true).schedule(new TimerTask() {
public void run() {
try {
System.out.println("Instrumenting");
ClassDefinition cld = new ClassDefinition(clz, buffer);
inst.redefineClasses(new ClassDefinition[] { cld });
}
catch (Exception e) { e.printStackTrace(); }
}
}, 500);
}
}